NIST NCSTAR 1-1

Federal Building and Fire Safety Investigation of

the World Trade Center Disaster

Design and Construction of

Structural Systems

(Appendices A-G)

David A. Fanella

Arnaldo T. Derecho

S.K. Ghosh

National Institute of Standards and Technology • Technology Administration • U.S. Department of Commerce

Appendix A

Supporting Documents for Chapter 2

This appendix contains the supporting documents that are referenced in Chapter 2 of this report. All of

the documents contained in this appendix are reproduced with permission of The Port Authority of

New York and New Jersey. Table A-l contains a summary of supporting documents and their location

within this appendix. The footnote numbers given in the table correspond to those in Chapter 2.

Table A-1. Supporting documents for Chapter 2. Footnote Number Document Title Page(s)

Section 2.1 - Building Codes Used In Design

1 Letter dated May 15, 1963 from Malcolm P. Levy (Chief, Planning

Division, World Trade Department) to Minoru Yamasaki (Minoru

Yamasaki & Associates)

132

2 Letter dated February 18, 1975 from Joseph H. Solomon (Emery

Roth & Sons) to Malcolm P. Levy (Chief, Planning Division,

World Trade Department)

133

3 Letter dated September 29, 1965 from Malcolm P. Levy (Chief,

Planning Division, World Trade Department) to Minoru Yamasaki

(Minoru Yamasaki & Associates)

136

NIST NCSTAR 1-1A, WTC Investigation 131
Appendix A

'®m\ \<mu-\

Trnrtys ^.©laTe ©if »tjsw t?®sis AP^ncii

©

i&ic Trirr^r"' "'^^

••.lCTM!V:?:)

itl't'itjhfh .Aiimtt-tit fj/A.?J(rc*/"J&H'i/0rxJlfAl/ j

WORLD TRADE CENTER 'j' .*

' C- ~ -

~ ?VS ttj*

C», »WMB!<S 01VIM O.N ptxciM

May 15, 1963

Mr. Minoru Yatrasaki

Minoru Yamasaki & Associates

1025 East Maple Road

Birmingham, Michigan

Dear Yana:

At a recent meeting with Mx. John Kyle, Chief Engineer, the subject of New York City Code compliance was further amended as follows:

"All consulting engineers and architects working on the World

Trade Center have been instructed to comply with the Code in preparing

their designs. Questions have arisen, however, in areas where the Code

is not explicit. It was agreed that in such cases and, where technological advances make portions of the Code obsolete, the consultants

may propose dt-signs based on acceptable engineering practice. All such

instances will be called to the attention of The World Trade Center

Planning Division. When preliminary designs have been completed, the Chief Engineer will reviex/ all design concepts with the. appropriate

municipal agencies before the consultants proceed with the final design".

LF:db

cc: Mr. J. Roth (ERS)

Sincerely,

Malcolm P. Levy {J

Chief, Planning Division

(2.1)

132 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 2

EMERY ROTH & SONS

GSO THIRD AVENUE. NEW YORK, N V lOO?-2 (2)2) 7S3-I733

RlCKARO both S«.. r. A. I. A. HAflRV J MARKI". A-' A CSTCLLt DCAL

JOStPH H. SOtOHON, A.t. A. RICMARC RCW. J«,A

February 18, 1975

Mr. Malcolm P. Levy

General Manager

World Trade Center Operations

Port Authority New York, New Jersey

1 World Trade Center

New York. New York 10047

Dear Mali

In accordance with the instructions issued by the Port Authority

at the start of the project, construction drawings for the World

Trade Center were to conform with requirements of the Building

Code of New York City, and any variations therefrom were to

be called to the attention of the Port Authority for final decision and authorisation. This procedure has been followed

in production of the contract drawings and, with the ex- ceptions authorized by the Port Authority noted below, the

drawings are in accordance with the new Building Code adopted in December, 1960. The Duilding Department reviewed

the tower drawings in I960 and made six comments concerning

the plans in relation to the old code. Specific answers

noting how the drawings conformed to the new code with re- gard to these points were submitted to the Port Authority on March 21, 1968.

We were instructed by the Port Authority to deviate from code

with respect to the following areas:

1. Omission of vent 3 from closed shafts. Noted to the Port

Authority by letter dated April 20, 1967.

2. Demising partitions to stop at suspended ceiling or bottom

of truss instead of running from slab to slab. Noted to

the Port Authority by letters dated November 9, 1967 and

June 6, 1969 with response on December 12, 1967. Prior

instruction on procedure from Port Authority dated January 26, 1966.

BCNlOB ASSOCIATES: VICTOR COR LAC m fflCO IIALOCN-CCBNAHD Kt«.StCR, A. t. A.- PHILIP 11«N, A. I. A. assoc i»Tts cxwciai rt»i»«oti • Bf« ei«m'i m »oot«i s eovoe<»<i. it » • *«<hui> o ncc*> • jow* icon* JOilPH l«3CMI»V0. J«.' JOHN M UIH-tB • «*l OHLAHDO- V«CTO« C SCALLO. A. I. » • JOHkt J, « EC R 111. J«.

RE: WORLD TRADE CENTER

NISTNCSTAR 1-1 A, WTC Investigation 133
Appendix A

emery both a sons ~2 ~ Febru;..»s» 18, 1975

3. Omission of fire protected openings on exterior valla

with separation of less than 30 feet. Noted to Port

Authority by copy of letter to MYA dated January 26,

1966.

4. Treatment of concourse level as "Underground Street"

noted by letter to the Port Authority on April 6,

1971, January 11, 1972 and May 7, 1973.

Fire detection and protection requirements specified for the

World Trade Center meet or exceed Building Code requirements

prior to the adoption of Local Law #5. Most other office

towers in the City of New York meet the minimum code requirements j

A. Telephone system for Fire Department use connecting

pump room and gravity tank room with all floors . A

six inch gong provided at permanent telephone at pump

room, first floor and gravity tank room. Telephone jacks

at all other floors protected by break glass boxes.

B. Standpipe signalling device : an eight inch gong located in the pump room and every 10 floors in the

elevator shaft ; an approved closed circuit strap key

enclosed in a sheet metal box at each telephone station

for fire department use.

The Building Code permits the use of louvered doors on toilet

rooms, janitor and electric closets located in 1 hour rated

corridors . There is no size limit specified for the louver,

but the Board of Standards and Appeals permits louvers of 2 square feet in 3/4 hour rated doors (which are required in 1 hour rated partitions) . Up until about 1968 most office

buildings had 1 hour minimum rated enclosures and louvered

doors in telephone closets and sleeves or small slots through

the floor. Since 1960, about 25 percent still have louvers

in the doors. In more recent buildings the floor openings

ha V3 been slabbed over.

Since corridor construction is required by code to be 1 hour

rated, it follows that louvered doors were acceptable in tele134 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 2

ROTH a SONS -3- February Id 1975

phone closets. Corridor partitions in the Trade Center Towers,

however, were designed to meet 2 hour rated construction at

the request of the Port Authority, to forestall any problems

with dead end limitations in the new code. It would require

investigation of individual floor tenant layouts to determine

if the dead end limitation of 50 feet for 1 hour construction

has been exceeded.

The original contract drawings, dated 7/31/67 and the Contract

Bid Sets dated 12/18/67 and 2/9/68 indicate 2 hour rated enclosures for the telephone closets with louvers in a FPSC, 1-

1/2 hour label door. The hollow metal door specification

written in 1967 and received by the Port Authority on 10/24/67

called for fusible link dampers on louvers in labeled doors.

Letters to the Port Authority dated 8/23/57 and 9/6/67 incated that variances had been obtained for omission of dampers

and requested instruction regarding this advice. The requirement for dampers was deleted from, the final draft of the

specification reviewed by the P. A. in Hay, 1968. Re quirement to meet provisions of underwriter's labs, S.S.A. and

Building Department was retained, however, for doors with

F.P.S.C. and hourly ratings.

Based on Port Authority comment3 on drawings received 4/17/69

and pursuant to a letter from the Port Authority to Tishman

Construction Company dated 4/20/69 instructing that such

changes be made, the wall of the telephone closet was changed

to 1 hour rated construction on 5/23/69 and the door was changed to F.P. with a 1-1/2 hour rating. Since the telephone closet was no longer a shaft with a 2 hour rated enclosure,

all floor openings left for future installation of cables had

to be firestopped. This admonition was reiterated in a letter

to the Port Authority dated June 25, 1973.

Please inform us if any additional information is desired.

Sincerely,

JHSiam

CC; Mr.R. Monti, Chiof Engineer/ PA

NISTNCSTAR 1-1A, WTC Investigation 135
Appendix A

£ Jlo-4

rirnm ip©ranp ©if kjkw toisus Aw^sioiaiiTY/

I J / \- ' J>

CKIIf. fLANNWO OiVlftCh

WORLD TRAPS CENTER

September 29, 1965

Mr. Minoru Yamasaki

Minoru Yamasaki & Associates

1025 East Maple Road

Birmingham, Michigan 48011

Dear Yama:

Wc have decided to adopt the new Building Code presently

existing in second and third draft form for The World Trade Center.

The Roth office is requested to revise floor plans as quickly as possible and on an accelerated basis to comply with

the provisions of this code. It is my understanding that the present drawings have been prepared to permit rapid conversion to the new code. Generally the tower core should be redesigned to eliminate the fire towers and to take advantage of the more lenient

provisions regarding exit stairs. No other major change to the core should be undertaken -without review by this office.

The structural consultants are instructed, by copy of this

letter, to revise structural design in accordance with the more

realistic criteria for partition weight allowance. The majority

of interior partitions, as noted in a previous letter, will consist,

of reinforced gypsum plank.

The Roth- office is requested to provide me with the dates

on which we can expect revised floor plans and also to indicate any changes in design schedule caused by these instructions.

olm P. Levy

cc: R. Bauts! (JBIJ) , J. Loring <JRLA) , 3. Roth (ERS) , J. Skilling

and L. Robertson (WSHJ)

Similar letter cent to Mr. Julian Roth (ERS)

136 NISTNCSTAR 1-1A, WTC Investigation
Appendix B

Supporting Documents for Chapter 3

This appendix contains the supporting documents that are referenced in Chapter 3 of this report. All of

the documents (with the exception of the Laclede Steel Company correspondence) contained in this appendix are reproduced with permission of The Port Authority of New York and New Jersey. Table B-l

contains a summary of supporting documents and their location within this appendix. The footnote

numbers given in the table correspond to those in Chapter 3.

NISTNCSTAR 1-1A, WTC Investigation 137
Appendix B

Table B-1. Supporting documents for Chapter 3. Footnote Number Document Title Page(s)

Section 3.3 - Damping Unit Tests

2 Letter dated June 22, 1 967 and enclosure from Don Caldwell of 3M to Peter Chen of SHCR

(WTC1-501-L; reproduced without appendices that are contained in WTCI-501-L)

139

3 "Test Program for World Trade Center Viscoelastic Damping Units," by Stephen H. Crandall of MIT, May 20, 1968 (WTCI-501-L)

146

4 "Test of Viscoelastic Damping Units for World Trade Center Tower Buildings," S.H. Crandall and L.E. Wittig, April 23. 1969 (Box 9, 233 Park Ave.)

158

5 Letter dated August 29. 1968 from Leslie E. Robertson of SHCR to Malcolm P. Levy of PONYA (WTCI-501-L)

179

6 Letter dated May 22, 1969 from Leslie E. Robertson of SHCR to Malcolm P. Levy of PONYA (WTCI-501-L)182

7 Letter dated June 2, 1969 from Stephan H. Crandall of MIT to John M. Kyle of PONYA

(WTCI-501-L)

185

X "World Trade Center Report No. DU-3, Viscoelastic Damping Units," by SHCR, June 2, 1969 (WTCI-501-L; reproduced without appendices that are contained in WTCI-501-L)

189

9 Letter dated November 5, 1971 from Malcolm P. Levy of PONYA to Don Caldwell of 3M

(WTCI-513-L)

196

Section 3.4 - Floor Truss Tests

10 Letter dated April 3, 1969 from David B. Neptune of the Laclede Steel Company to W.C.

Borland of PONYA (WTCI-503-L)

197

1

1

Internal Laclede Steel Company memo dated May 15, 1969 from David B. Neptune to R.D. Bay (part of WTCI-82-I)

198

12 Internal Laclede Steel Company memo dated September 7, 1967 from J.R. Paul to A.C. Weber (WTCI-85-I) 202

13 Letter dated August 10. 1967 from A. Carl Weber of the Laclede Steel Company to Wayne

Brewer of SHCR (WTCI-235-L)

203

14 Letter dated April 19, 1968 from Wayne A. Brewer of SHCR to R.M. Monti of PONYA

(WTCI-87-I)

205

15 Internal Laclede Steel Company memo dated March 1 8. 1969 from David B. Neptune to R.D. Bay (part ofWTCI-82-I)

207

Section 3.5 — Stud Shear Connector Tests

16 Letter dated November 3, 1969 from James White of SHCR to Lester S. Feld of PONYA

(part ofWTCI-253-L)

208

17 Contract dated January 6. 1970 from Guy F. Tozzoli of PONYA to Roger G. Slutter of the

Fritz Engineering Laboratory, Lehigh University (part of WTCI-253-L)

210

138 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

trtflRM nillCtS . 2J01 HUDSON ROAD • ST. PAUL MINKISOIA 'jbiH • Ul. 723-U1G

Industrial Tape Division

June 22, 1967

Dr. Peter Chen

Skilling, Helle, Christiansen & Robertson

230 Park Avenue

New York, New York

Dear Peter:

Attached are two copies of a report explaining the results

of our teats on full size daopers. I trust these will reach you

in adequate tiae for your study before our aeeting next Tuesday

,

June 27, 1967, in St. Paul.

Very truly yours,

D. B. Caldwell

Project Engineer

Acoustic Products

NISTNCSTAR 1-1A, WTC Investigation 139
Appendix B

I. Introductio n Vibrational motion of tall buildings and structures can be

damped out by the employment of dampers as non-load carrying

elements in the structure.

Most of the dampers arc designed so that they convert part

of the mechanical energy into heat and thus rcduc** the

amplitude of motion. The medium in which this transfer

of energy takes place is generally either a viscoelastic

material or liquid.

In this report we discuss only a particular damper employing

a viscoelastic material as the damping medium.

II . Damper Shape, and Desired Characteristic

In general the damper is comprised of two viscoelastic layers

bonded between three rigid surfaces, planar on at least one

surface (Figure 1).

The damper will be placed such that the application of the

load generates shear deformation in viscoelastic material

such as shown in Figure 1 . Due to specific requirements of the World Trade Center, the

dampers should meet the following requirements within the

temperature range 72-7 8*F and up to 50% R.H. (see technical

specification >.

a. Average Stiffness

The damper should have a total average stiffness

cf at least 12,000 lbs. axial load at the specified

frequency of 0.1 C/sec. and at a deflection of 0.02".

b. Average Los 3 Factor (tan % ) The average damping factor or loss tangent should be

at leaat 0.6 at 0.1 C/sec.

C Fatigue

After 100 cycles at 20x10-3 amplitude and 0.1 C/sec.

G" shall not decrease by more than 20% when the

damper temperature has returned to its initial

value (first cycle).

140 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

- PllgC 2

d . Ultimate shear strength

The damper, when loaded in fdienr should he able to

withstand **8,000 lbs. of l«.ad - thin includes both

static plus riynair.ic losd.

e „ Static and dynamic deformution

Maximum amplitude of vibration i.e. viscoelastic shear

deformation will he around 20x10-3 inches dynamic and

30x10-3 inches static.

In order to fullfill the above mentioned requirements a viscoelastic material with the proper dimension was selected. Figure 1 shows the actual damper with all the dimensions.

Ill . Test Objective and Procedure

a. Test objective

For the purpose of establishing the effectiveness and

the efficiency of dampers the following, properties were selected for evaluation.

1. G" , Iosb shear modulus as a function of temperature

(T) and fatigue cycle (N).

2. and W^oo an^ w t

, work done in the first and one hundreth cycles and total work done in 100 cycles

respectively.

3. Temperature rise accompanying fatigue (100'b and

L000 cycles^

U . Loss tangent os a function T and N.

5. G* and G* storage and complex shear modulus as a function of T and N.

6. Total heat production in viscoelastic material.

7 r Ultimate shear strength.

b. Test procedure

Tfcen ty- two full size dampers were prepared for testing.

For the purpose of monitoring the temperature of viscoelastic material in the da«\pcr a thermocouple was imbedded

in the center of viscoelastic part as shown in Figure 2.

NISTNCSTAR 1-1A, WTC Investigation 141
Appendix B

- I»a$*e 3

The shear deformation whs deter ted hy an L.V.D.T.

which was Attached I «> the dntnper in Much n wny that

the coil of the L.V.D.T. wok rigidly fastened to the

stationary part of the damper while the core was

clamped to the moving part cf th€ dumper, when

cyclic load wan applied, as shown in Figure 2.

Tests were carried out at two different locations

and on two similar closed loop-feed hack machines.

Four 'ampers were tested at M.T.S. Corporation in

Minneapolis and IS samples were evaluated at

Materials Research Laboratory Inc. in Chicago.

The testing environment, as far as temperature and

humidity control Is concerned, was not ideal.

In general the following test procedures were followed

at both laboratories.

The damper was rigidly mounted, between the machine

ram and the load cell and the L.V.D.T. was connected

through ram control panel to the X axis of an X-Y

chart recorder. The output of the load cell was made

to drive the Y axis of the chart. By the use of

micrometer head CFigure 2) the L.V.D.T. was calibrated

so that one inch of chart in the X axis represented

. 00U inches of shear deformation. Load cell was also

calibrated electronically such that one inch of chart

was equivalent to **000 pounds in the case of MTS

machine and 5000 pounds for MRL machine.

Temperatures were recorded by the use of two TC's

and a two ch«nr>el recorder ir. vhich one citttmml

recorded viscoelastic temperature and the other

monitored the environment temperature. An ice bath

was used as a temperature reference point.

The machines were set on strain control. Signal from

L.V.D.T. was compared to n preassigned signal from

function generator which was set on sine function with

20x10-3 inch maximum amplitude and .1 C/sec frequency.

Before the start of test run the recorder was calibrated

and the output of both TC 1 and TC 2 were recorded.

Tests were conducted on each damper for 1 to 100

cycles and in one special case a 1000 cycle test was

performed. After a 100 cycle test the damper was left

to cool down and tested at the initial (first cycle)

temr erature.

142 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

Pace U

I V . Ann] ys i s of TVs t J* »* sn |_ 1J» The results obtained 1 rom rl »«•?:«» Icmh were in I fortn of

hysteresis loops (II. 1 . ) - fmrr vn . t\i spl jirrtnent ax shown in

Figure 3. Assuming that" tin* linear vis<oel««t ir theory is

applicable tn this -msp, 1 he rr lr. t i r.ns!i ps liriWi-f-n dvrt«fi«i«*- proi^prties of damper for fchr rnse of controlled ain\i8oidal

displacement- of the form

2 = ^0Sin*Jt

are as fol lows :

=

tf 0 Sin u)t I cr = cr-0 Sin (Ut S > 2

C8" = ojo Sin g 3

<To

D = tan £ = G"/G ' 5

G* = (G' 2 G" 2

) 1 /2 6

wx

= TT G

M ^

2 V 7

J- = dicplacement fin. )

yCQ

= maximum displacement (in.)

W = angular velocity (rnd/sec)

t = time (sec)

CT = shear stress (psi)

Co = maximum shear stress (psi)

0 - 9-/1 - shear strain (in. /in. ) T = thickness of

v.e, material (in.)

X - jL /T = maximum shear strain (in. /in.) 0 o o

where

NISTNCSTAR 1-1A, WTC Investigation 143
Appendix B

laye S

C. ' , O" and (".* = innij'.p, I <>«,•; an<l r»wnple* fihenr

nin'ht 1 ii.s ( jim i ) D = tunS ~ loan tangent

s di kbi p/itoil iTirrKy i n nr.s cyrle (in-lb.)

V = 2AVT = total volume ni v.e. material (in^)

Ay = viscoelastic shear area (in*)

The areas of H.L.'s were measured by a plnnimeter and the dissipated

energy in one cycle, van calculated as follows:

where

Wl

= Ap

C lC

2

Ap = area of the H.L. (in^)

C\ = force scale factor (lbs/in)

C2 = displacement scale factor (in/in)

knowing the total volume of viscoelastic material V and also the

maximum strain £* 0 the value of C" can be readily calculated from

Equation 7 i.e.

G" = Vi/TtiT* V

By substituting G" in Equation 3 Sin&and consequently tang ia

calculated i.e.

tanS = z*i -(G"«-0

)2]i/2 = Iw^n2 - SI7

]

1/1

'

also from Equations 5 and 6 we obtain G' and G*.

Ultimate shear strength were measured on a 6C,o00 lbs. capacity

universal testing machine, and during testing load-deflection

was recorded.

Calculations were also made in regard to heat generation and

subsequent storage and dissipation of heat. Total heat generated

was obtained by assuming n linear relationship between dissipated

energy W and the number of fatigue cycles, N.

From this linear relationship the total energy dissipated in 100

cycles will be

W , = Wl

! Wl0Qx 100 ft-lb "total 2i+

144 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

~ Page 6

and the hr/jt crnrmtcl Q t in

Qt = v total /7 7S.2 liTll The total heat ncni-rotccl can be divided into two parts,

1) heat stored in the viscorlnntic material, QR and 2) heat

dissipated through conduc i ion . convection and radiation to

other parts of the system, Q^j i.e.

Qt = Qs Qd 0

Since we measured the tempern ture rise nnd also know the physical

properties such as density und specific heat of the viscoelastic

material, Q8 can readily he calculated. The following formulas

were used in this analysis.

Tables 1 to U represent the numerical results and Figures 4 to 7

represent the graphicnl presentation of these results.

V . Cone lusion

Although the number of test runs on Full size dampers arc insufficient for a precise statistical analysis, nevertheless

the following conclusions can be drawn from the results.

G" and consequently energy dissipation per cycle W are inversly

proportional to temperature. The relationship seems to be approximately linear. The relationship of temperature rise to

fatigue cycle is also, for the first one hundred cycles, approximately linear, but due to the fact that most of the

generated heat is dissipated to the. environment, it seems

that after U00 cycle (see results on 1000 cycle test) a steady state is approached. It is therefore safe to assume

that G" or W per cyele remain relatively constant afterwards.

The effect of temperature on loss tangent in this range (70-82°F)

seems ro be negligible although a slight increase in loss tangent

with temperature is noticable (Figure 6).

It should be observed that the temperature in the v.c. material

was measured in a transient state and the actual temperature

in the v.e„ material was possibly slightly higher than those

shown, but the difference cannot be more than 1.0° or at most

Q8

= M^CAT

Qt - Qs = <?d

10

1.5°F.

NISTNCSTAR 1-1A, WTC Investigation 145
Appendix B

T«it Program

for

World Trade Center Vieeoaleetic Damping Unite

Proposed by

Stephen H. Crondall

Kay 20, 1968

146 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

2

1. Test Sample

Flfcy-tvo sample damping unite shall be fabricated and delivered to

the Acoustics and Vibration Laboratory, Room 5-024, M.l.T. These units

shall be identical to those which are to be supplied for installation

in the World Trade Center towers under Contracts VTC-219.00 and WTC~224.00,

except that each test sample shall have one thermocouple embedded in the

viscoelastlc material. The thermocouple specifications shall be delivered

to Professor Crandall.

The test samples shall be numbered according to a random pattern and

ten of the units shall be sent to the Tort of New York Authority for

storage and subsequent testing for aging effects.

2. Test objectives

Tho major portion of the test shall be devoted to determining the

statistical distribution of the following basic mechanical properties

of the damping unite:

Loss factor for steady cycling at 0.1 Hz.

Dynamic stiffness for steady cycling at 0.1 Hz.

Ultimate load when deformed at the rate of 0.5 in. per min.

Ultimate displacement when deformed at the rate of 0.5 In.- per min.

Thirty samples shall be tested to determine these properties. Before

beginning these tests four samples shall be cycled for 10,000 cycles (If

failure does not occur earlier) to determine the possibility of fatigue

failures for the dampers. If fatigue failures do occur In these four

samples, it will be proposed that some of the thirty samples for the basic

NISTNCSTAR 1-1 A, WTC Investigation 147
Appendix B

3

statistical tests be used to obtain additional fatigue information (after

loss factor and dynamic stiffness measurements have been made) . These

samples will not then be available for the ultimate load test under deformation at the rate of 0.5 in. per min. The decision as to how many

samples to divert to fatigue testing in this manner shall be made by

Professor Crandall in consultation with all interested parties.

In addition to the fatigue teat and the basic test for ctatlstlcal

distribution, supplementary tests shall be asde on the remaining eight

samples to obtain additional engineering information concerning the behavior

of the damping unite. These supplementary tests ere designed to elicit

information on now the energy absorption of a dasper is affected by:

(1) Preload on th»

(11) Preliminary high frequency cycling.

3. Tsst Facilities

All cycling tests shall be performed on a special test frame In which

one or two damping units can be cyclically deformed as the structure Is

sheared by a motor-driven eccentric. The test frame shall simulate the

average local elasticity of the damping-unit connectors in the World

Trade Center towers. The amplitude of the test-frame deformation shall

be controlled by the size of the eccentric. The amplitude of the damping

unit deformation depends on the dynamic stiffness of the damping unit

and will vary from element to element and will vary with temperature for

any one element. Damping unit test amplitudes shall be specified in

terms of an equivalent amplitude measured cm a steel dummy unit whose

148 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

4

stiffness is 650,000 pounds per inch. The frequency of the cycling shall

be controlled by the choice of sprockets In the ci»«»1n »lrlv.? brtveen the

motor-drivun reducer and the eccentric drive-shnic. Forces in the damping units shall be measured by strain-gage load cells nnd deformations

of the units shall be measured by L.V.D.T.^a. Force-din placement curves

shall be recorded on an on-line X-Y plotter. The special test structure

shall be disassembled at the conclusion of the tests and seot to the New

York Port Authority for storsgc.

The ultimate load testa shall be performed on a annually operated

hydraulic teat leg machine with a capacity of 100,000 pounds, ine iaaLi<*~

asatati** ahall be the same as in the cycling tests. The operator shall

endeavor to maintain the rate of deformation at a nearly uniform rate

as closa as possible to 0.5 in. per min. The actual rate of deformation

shall be recorded.

A. Specifications for Fatigue Tests

These coats on four units chosen at random shall be performed prior

to the basic statistical tests described in Section 5 below.

(a) The cycling rate shall remain within t 22 of a fixed value lying

within the range from 0.08 to 0.11 Hz (4.8 to 6.6 cycles per minute).

(b) The mean load on the damping unit during a cycle shall be zero.

(c) The cyclic amplitude of the test-frame displacement shall remain

vithin z 2Z of a fixed value lying within the following ranges.

(i) Two damping units shall be tested with equivalent

NIST NCSTAR 1-1 A, WTC Investigation 149
Appendix B

5

Amplitude* In • range from 0.016 to 0.022 Inches.

(11) Two damping unite ah*11 be tested with equivalent

amplitudes in the range from 0.027 to 0.033 inches.

(d) The ambient temperature and humidity and the temperature of

the viscoelastic material shall be recorded at hourly intervals during

the fatigue tests.

(e) Force-displacement curves for each specimen shall be recorded

by an on-line X-Y plotter at hourly intervals during the fatigue teats.

Clocktime and cycle number shall be noted.

(f) If at the end of 10,000 cycles a unit has not obviously failed

and its force-displeccment curve has not altered dramatically the cycling

shall be stopped and the unit shall be removed from the cycling test

structure and placed in the ultimate-load test machine. There it shall

be subjected to an approximately uniform rate of deformation as near

to 0.5 in. per min. as possible. Force and displacement ehall be recorded until failure occurs.

If all four units survive 10,000 cycles and if their subsequent ultimate loads are each greater than 35,000 pounds it shall be concluded

that fatigue is not a serious hazard and no further considerations shall

be given to fatigue in this test program.

If, however, one or more of the four units foil to meet the above

requirements, it shall be necessary to consider very carefully whether

additional fatigue testing should be carried out. Such Additional

fatigue teste would be carried out (on fhitrtpw «Mwj«i*ii H"«*n the 30 baelc

statistical test-samples) la lieu of the ultimate-load test.

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6

5. Specifications for Basic Statistical Teets

These teata shall be performed on thirty specimens. To determine,

dynamic properties of the damping unite under uniform cycling each e ample

shall by cycled for 100 cycles at a uniform rate. The cample shall then

be allowed to cool dovn to its initial temperature before going through

two additional cycles. Force-displacement curves and temperature data shall

be recorded aa described below. After the cycling test each sample ehsll

be deformed to failure in an ultimate-load test (if additional fatigue

testing is decided upon, some fraction of the samples shall be given

£«wiguu wcBwo iu liuu v>r mIwj.ITim t» !«•« CCStw) •

The following apecifications apply to the teats for dynamic properties

under uniform cycling.

(a) Tha cycling rate shell remain within 1 21 of a fixed value lying

with the range from 0.08 to 0.11 HZ (4.6 to 6.6 cycles per minute).

(b) The moan load on the damping unit during a cycle shall be xero.

(c) The. cyclic amplitude of the test-frame dlsplscemcnt shall remain

within i 22 of a fixed value lying within the following ranges.

(1) Twenty units shall be tested with equivalent amplitudes

in the range from 0.016 to 0.022 inches.

(11) Ten units shall be tested with equivalent amplitudes

In the range from 0.027 to 0.033 Inches.

(d) The ambient temperature and humidity and the temperature of the

viscoelostic material shall be recorded for the l

8t

, 10

th

, 20

th

, 50^,

C hi 8 it 100 and 101 cycles for each specimen.

(o) Force-displacement curves shall be recorded by an on-1 me

NISTNCSTAR 1-1A, WTC Investigation 151
Appendix B

7

X-Y plotter for the l", 2

nd

» 10

th

, 20th

. 50

th nnd 100th cycle, for each

specimen. At the end of the 100

th cycle, the de formation nlanll he suspended

until the viecoolaotie material returns to its inJUnl twaperature, plus

or minus 0.2° F. The time required to reestablish the initial thermal

condition shall he recorded. Then cycling shell be resumed for an additional two cycles. Force-displacement curves for cycles 101 and 102

shall be recorded.

The following specif ications apply to the ultimate-load test.

(f) Tho daaping units shell be transferred from the cyclic-test

franc to a 100 , 000 pound hydraulic test machine. Half of the units ahall

be tested in tension and half in compression.

(g) Ambient t*wnn*r»£»;r£ •si h^idltj tzi CbS tSSp»r«tuiT«i <tt Vum

viscoeloetlc material shall be recorded at the beginning of each ultimateload tost.

(h) Tho testing machine shall be manually controlled to provide &

nearly uniform rate of deformation as near as possible to 0.5 inches per

minute.

(1) Force-displacement curves to failure shall be recorded on an

on-line X-Y plotter. The time history of displacement shall also be

obtained.

(J) Failure modes shall be noted and photographed where informative.

6. Supplementary Teats

Four specimens shall be tested to investigate the effect of preload

on the energy absorbtion of the damping units. These tests shall be

152 NISTNCSTAR 1-1A, WTC Investigation
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8

similar to the cycling portion of the basic test vith the exception that

inatead of cycling about a mean load of ten? the cycling shall take

place around non-aero tensile and compressive loads.

The specification! for the preload test are given below.

(a) The cycling rate shall remain within ± 22 of a fixed value lying

vith the range from 0.08 to O.U Hz (4*8 to 6.6 cyclea per minute).

(b) The damping units shall be inserted into the test frame in such

a manner that the mean deformation of the element during the cycle takes

on tho following values.

(i) One unit shall be tested with a cyclic mean equivslent

elongation in the range between 0.009 and 0.011 inches.

(11) Cm* wuXi. hall be cestea with a cyclic mean equivalent

elongation in the range between 0.018 and 0.022 inches,

(lil) One unit shall be tested with a cyclic mean equivalent

compression in the range between 0.009 and 0.011 Inches,

(iv) One unit shall be tested with a cyclic mean equivalent

compression in the range between 0.018 and 0.022 inches.

(c) The cyclic amplitude of the teat frame ahall remain within ± 22

of a fixed value which shall produce an equivalent amplitude within the

range from 0.018 to 0.022 inches.

(d) Tho ambient temperature and humidity and the temperature of the

viecoelostic material shall be recorded for the l

at

, 10th, 20th, 50

th

,

100th and 101w cycles for each specimen.

(e) Force- displacement curves shall be recorded by an on-line X-Y

plotter for the 1

8C

, 2nd, 10th, 20th

, 50th

. and 100th cycles for each

NISTNCSTAR 1-1A, WTC Investigation 153
Appendix B

9

epeciiacm . At the end of the lOO**

1 cycle, the deformation ahull be suspended

until the viscoelaetlc material rcturna to ita initial trir.p«rrtture, plua

or minus 0.2 F. The time required to reestablish the initial thermal condition shall be recorded. Then cycling shall be resumed for an additional

two cycles. Force-displacesent curves for cycles 101 and 102 shall be

recorded.

Four specimens shall be tested to investigate the effect of higher

frequency cycling on the energy abaorbticm of the damping units. Each

specimen shall by cycled for ten cycles at the standard amplitude and

frequency. Then the frequency shall be Increased and the amplitude decreased (or left unchanged) and the unite cycled tor 100 cycles before

returning to the standard amplitude nod frequency. Force-displacement curves

ahnll be recorded before and after the high frequency cycling as described

below.

Specifications for the high-frequency teat are given below.

(f) All four specimens shall be cycled for ten cycles at a fixed

frequency between 0.08 and 0.11 Hx with an equivalent amplitude between

0.018 and 0.022 inches.

(g) Ambient temperature and humidity and the temperature of the vincoclaetic material shall be recorded for the l

8t and 10*** cycles.

(h) Force-displacement curves shall be recorded on nn on-line X-Y

plotter for the l

eC and 10

th cycles.

(i) For two samples the equivalent amplitude, shall be decreased to

a fixed value within the range from 0.009 to 0.011 inches and the cycling

frequency shall be increased to

154 NISTNCSTAR 1-1A, WTC Investigation
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10

(1) A value between 0.23 and 0.27 lis for on« »m»ple.

(11) A value between 0.46 and 0.5* H* for on© f»*mpl«.

For the other two samples the equivalent amplitude slmll be ir* intnlncd

within the range 0.018 to 0.022 Inches and the cycling frequency ehall

be increased to

(111) A value between 0.23 and '0.27 lis for one sample.

(Iv) A value between 0.46 and 0.54 Hx for one sample.

The specimens shall be cycled for 100 cycles at the higher frequencies

Indicated.

(J ) Ambient temperature and humidity and the temperature of the visco-

. . ... »r f-K t-K »v. ..~th bImmk ttovci jla a onaxx oc recoroec at the i0"""» 20 , 50 and 100

high-frequency cycles.

(k) Force-dlaplacement curves shsll be recorded for the l

8t

, 50

th

, and

100 high-f roquency cycles.

(1) The frequency and equivalent amplitude for each specimen shall

now be returned to the values eatabliehed In (f) above. The time elapsed

while making this change shall be noted. The specimens shall then be

cycled for ten cycles as in (f). The measurements In (g) and (h) shall

be repeated.

7. Report of Test Results

The dynamic characteristics of the viscoelastic damping units ss

determined by these tests shall be reported as follows. For each of the

parameters listed below a statistical distribution diagram shall be given

along with values for the mean and standard deviation.

NISTNCSTAR 1-1 A, WTC Investigation 155
Appendix B

11

(a) For the first and on* hundred and first cycle* of steady cycling

at nominal frequency of 0.1 Ha and nominal equivalent amplitude of 0.02

inches (and 0.03 inches) the following parameters.

(1) Dynamic stiffness

(11) Loss tangent

(ill) Energy dissipated

(b) For ultimate testing st a nominal rate of displacement of 0.5

Inches per minute tension and compression) after previously enduring 102

cycles at nominal frequency of 0.1 He and nominal equivalent amplitude of

0.02 inches (ana 0.03 inch«») t»s fcli~*in« p?r«m*t.»r»

.

(1) Ultimate strength in pounds

(11) Ultimate deformation in inches

Tic results cf the £*t±!»»« i«v«atiaation shall bs eaatrlbcd . Either

the ability of these units to endure repeated loadings shall be verified

or an S-N type diagram shall be given.

The results of the preload investigation shall be described. The

energy obsorbtion capabilities of a preloaded damping unit shall be graphically compared with that of a unit without preload. The results of the

high-frequency cycling test shsll be described. The energy abeorbtion of

a damping unit before and after high-frequency cycling shall be graphically

compared.

An analysis shall be made of the effects of ambient temperature and

element temperature on the dynamic characteristics of the damping units.

Graphs shall be plotted of actual element displacement, cyclic energy loss

and loss tangent as a function of element temperature.

156 NISTNCSTAR 1-1A, WTC Investigation
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12

In addition to giving dynamic characteristics for the damping units

eeparately a discussion shall be given of the cyclic teat frame and ita

interaction vlth the damping units. Hie force and displacement of the

eccentric driver shall he recorded for certain caaea ao that the total

energy input to the fraas can be compared with the loos in the damping

unite.

/llx original X-Y plots. «itb necessary identification shall be

included in the report.

NISTNCSTAR 1-1A, WTC Investigation 157
Appendix B

Test of V i scot; las t ic Damping Units

for World Trade Center Tower Buildings

by S. H. Crandall

L. E. Wittig

Summary

Tests have been performed on 39 samples of the vlscoelastic

damping units proposed by 3-M for the World trade Center Towers to

determine the distribution of their mechanical properties and to

ascertain their effectiveness under a range of off -design operating

conditions. It was found that although there is considerable variability of properties from unit to unit in a batch and from one batch

to another, the energy absorbing capabilities of the elements are

generally adequate to provide the expected damping under design conditions and that the elements do perform satisfactorily under limited

variations of: loading conditions; speed of oscillation; duration of

oscillation and ambient temperature.

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TABLb OF CONTENTS

I Introduc t ion 3

II Description of Tests 5

III Results of Tests 10

IV Conclusions 16

V. Suggestions for Further Testing lo

References 21

Appendices

A. Effect of Frame Compliance on Amplitude of Element Elongation

6. Sample Calculations

C. Reduced Data

D. Effect of Elevated Temperatures on Viscoelastic Damping Elements

E. Literature on Vibration Tests of Buildings

F. Raw Data

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NISTNCSTAR 1-1A, WTC Investigation 159
Appendix B

I. Introduction

In order to control the tendency of the World Irade Center 'lowers

to sway under the acticn of high winds it is planned to increase the

inherent structural damping of the buildings by attaching viscoelastic

damping elements at the major structural joints connecting floors and

columns. The damping elements are bolted between the columns and the lower

members of the floor trusses in such a way that the elements are forced

to elongate (or shorten) whenever the buildings sway. These damping

elements have been designed by Skillinr,Helle, Christiansen and Robertson

(SHCR) and fabricated by Minnesota Mining and Manufacturing Coir.pany (3-M).

See Reference [1] for background information and the results of tests by

3-M on 22 prototype units. The present series of tests has been conducted

to supplement and to serve as an independent check on these earlier tests.

Twenty units were tested according to a basic or standard test

which closely paralleled the earlier 3-M tests. The standard test consists

of two parts: a cycling test and an ultimate test. In the cycling test

an element's elongation and force is monitored for 100 cycles as it undergoes

simple harmonic motion at the design amplitude and frequency. From these

measurements it is possible to evaluate the following important mechanical

parameters for the elements: the dynamic stiffness k (kips/inch), the

energy dissipated per cycle W<inch-lbs) and the loss tangent, tan <j>, and to

ooserve how these parameters change during a period of steady cycling which

lasts for 100 cycles (16.7 minutes for the design frequency of 0.1 Hz). In

the ultimate test the ele-nent is stretched (or compressed) at the steady

rate of 0.5 inches per minute until failure occurs. The elongation and

force history are monitored and the ultimate values of each are recorded.

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In addition to the standard test. 19 additional test-* were performed to investigate the endurance capabilities of the elements and

to investigate their operation under conditions different from the design

conditions prescribed in the standard tests. The conditions tested

included variations in amplitude and frequency, variations in ambient

temperature and the ef f ect-of -superpos ing a static preload on the

simple harmonic loading employed in the standard cycling test.

The principal differences between the standard cycling tests of

this report and those cf reference [1] arise from the differences in

test facilities. The tests of Reference [1] were performed in a

serve-controlled testing machine which maintained a fixed (single) amplitude of 0.020 inches throughout the test. The tests described herein

were performed in a specially built test frame (see Fig. 1) which was

intended to simulate the structural environment which the elements will

see when they are fastened in place in the World Trade Center Towers.

During the test the frame is periodically sheared by a motor driven

eccentric (see Fig. 2). The amplitude of the frame shear is controlled

by the "throw" of the eccentric. The damping element under test (see Fig. 3)

is forced to expand and contract as the frame is sheared. The element

elongation amplitude depends on the relative stiffness of the frame and of

the. clement itself. The precise relation is somewhat complicated and is

developed in Appendix A. It is sufficient here to realize that for the

tame frame shear (same sized eccentric) the element elongation amplitude

for a soft element will be greater than for a stiff element.

In order to describe the frame shear in a meaningful vay the elongation amplitude of an aluminum alloy "dummy" element (see Fig. 4) with a

NISTNCSTAR 1-1 A, WTC Investigation 161
Appendix B

stiff ners of 600 kips/inch was measurtd and c c e^J^aj^ntarap] itude. During the actual tefts the elongation anpi i t u<J* Cot the viscoelastic elements were greater or less than tt>e equivalent amplitude

depending on the stiffness of the clement under test. Three different

sized eccentrics were em^loyrd The standard tests were performed using

an eccentric which produced an equivalent amplitude of 0.019 inches. The

ether eccentrics produce equivalent amplitudes of 0.C10 inches and 0.023

inches. The frequency of cycling during the standard tests was approximately 0.1 Kz (actually 0.0989 Hz) . This- corresponds tc a period of 10

seconds per cycle (actually 10.11 second? per cycle). Other tests were

also run at two and c half times this frequercy, and at five times this

frequency

.

II. Description of Tests

A. Test Frame

All cyclic tests were performed on a special test frame,

(set Fig. 1). This special frame was constructed for these tests because

it was felt that the damping units should be tested in a structural

environment similar to that in which the dampe. rs will be installed in the

World Trade Center Towers. The test frame allows the damping units to

deform mere naturally than they would deform if tested in. a standard testing machine . For example, the damping units tend to rotate somewhat when

they ere elongated in either the test frame or in their building environment.

A stanGard testing machine, however, would not allow such rotational moticn.

The test frame also permitted us to check the effect of small misalignments in the installation of the dampers.

The test frame is goemetrically quite similar to the truss-outer

wall portion of the buildings. Dan ping units are held in the test frame

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162 NISTNCSTAR 1-1A, WTC Investigation
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vith 1-inch diameter A4'.I0 holts in single sdc/ir r<i: >-m v-i<<) ami wili!

7/8 inch diameter A "i

H

j> bi<jts in do'.J.lc shiv-i on <>.. olh»'i eicJ , corresponding to their installation in the buildings. A 1100 ft-lb. impact

vrench was used to tighten the bolts (see Fig. 5) according to turn-ofthe-i'ut regulations? [2]- fhe o>ain requiiement c£ tlicsc regulations is

that after the nut hai been brought up tight with a hand wrench the power

wrt-nch 1s applieJ t:, turn the nut fhrcuc.h an additional 180°. New bolts

were used for each test and r-him material was used when needed for proper

alignmer. t

.

When testing the dampirg units, the whole test frame was deformed

sinusoidal ly by a motor driver eccentric (see Fig. 2). The equivalent

amplitude referred to in the various tests is the elongation amplitude

that a lossless elastic member vith a stiffness cf 60C,00G lbs. /in. would

experience if it were to be belted into the test frame instead of a

damping unit (a more complete discussion of the sti ffness of the test

frame and its affect cn the elongation amplitude of a damping unit is given

in Appendix A)

.

The test frame was located in a temperature controlled room. The

temperature and himidity were recorded during all tests. For all tests,

except when specially noted, the temperature has held at 75°F + 3°F.

B. Standard Cycling Test?

The roost common test that was perfcrmec is referred to as

the standard statistical test. This test was carried out on the test

frame described above. The equivalent amplitude during this test was

19 mils (one mil equals O.C01 inches); the period per cycle was 10.11 seconds.

The stardard test was intended to be somewhat similar to tests performed

by 3M Company so that our results could be compared to their results.

-CNISTNCSTAR 1-1A. WTC Investigation 163
Appendix B

Dutirg a standard test the damping units were cycled IGC times,

and data was taker ou the 1st, 2nd, 10th, 20th, 50th ar<.. 100th cycles.

The units were then allowed to reJax Cor 20 minutes and more c.a t a war

taken on the 101st and 102nd cycles.

Damper extensions and contractions were measured with an LVDT

(linear variable differential transformer).. The LVDT me mounted ?s

shown in Ug. 3 so that the total motion between the two ends of the

damper was measured along the central axis. It should be noted that in

this respect these tests differ from those of 3-M where only the

relative motion betveer two internal points' within the damper was

measured. The axial force apnlicd to the danper wa? measured with a

strain gage dynamometer located in the angles thai: connect the dampers

to the truss. The temperature of the viscoelastic layer was monitored

by a thermocouple embedded in the viscoelastic material. The LVDT and

the force gafie were calibrated for each test.

Outputs from the LVDT and the force gage were fed into the same

x-y recorder shewn, on the left of Fig. 6. Because cf the vi rccelastic

behavior of the damper there is a phase shift between the force signal

and the elongation signal. The phase shift causes the force-elongation

plot to form a closed hysteresis loop during each cycle of oscillation.

The area of the loop is directly proportional to the energy dissipated

during the cycle. The loss factor and the dynamic stiffness of the

damper can also be determined from this plot. The output frcm the thermocouple was fed into a second x-y recorder shown in the right, in Fig. 6

and plotted as a function cf time.

During one test the rotational moticn of the damper and the moment

applied to the damper vert measurcc. From this information the amount

energy absorbed by the damper due to rotational motion was. calculateo.

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C. Special Cycling Tests

Besides the standard statistical tests, some additional

cyclic tests were performed to determine further properties of the

damping units. Four different types of tests were carried out:

(i) endurance tests, (ii) preload tests, (iii) higher frequency tests,

and (iv) one endurance test at an elevated temperature.

The purpose of the endurance tests was to check the fatigue

life of the damping units. These tests were quite smmilar to the

standard tests descrioed earlier except that the total number of cycles

was much greater. Two tests were run with an equivalent amplitude of

10 mils for 10,000 cycles, and two tests were run with an equivalent

amplitude of 19 mils until fatigue was noticed.

The preload tests were performed by bolting the damping

units into the test frame when the frame was slightly deformed from its

neutral position. This procedure forces the damper to oscillate about

a nonzero mean displacement. Such a condition could easily arise in

the World Trade Center Towers if the swaying oscillation took place

about a static sway due to the steady state wind components. These

tests were also performed in a manner similar to that of the standard

test. However, during the four preload tests the mean equivalent

pre-elongations were approximately + 10 mils and +_ ?0 mils.

The higher frequency tests were conducted to see if oscillations at frequencies corresponding to the hip.her modes of the buildings

would cause any deterioration in the effectiveness of the dampers.

Higher test frequencies were obtained by changing the sprockets of the

motor transmission system. During these tests the damper specimens

were first cycled 10 times at the standard frequency of 0.1 Hz and at

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NISTNCSTAR 1-1 A, WTC Investigation 165
Appendix B

the standard equivalent amplitude of 19 mils. The frequency of the

forced oscillation was then changed to either 0.25 Ha or to 0.50 Hz;

the equivalent amplitude vas either held the same or reduced to 10 mils.

The specimens were cycled 100 times under these new conditions. After

these 100 cycles the frequency wss returned to 0.10 Hz and the equivalent

amplitude was returned to 19 mils. The specimens were cycled 10 more

times to see if there was any noticeable change in the damper properties

since the original 10 cycles.

The last special cyclic test that we performed was an

endurance type test with the exception that the ambient temperature was

10°F above the normal 75°F. The results of this single test were discussed in some detail in a preliminary report which is included here

as Appendix D.

D. Ultimate load Tests

All of the damping units from the standard statistical tests

and the endurance tests were subjected to an ultimate load test. The

ultimate load test consists of stretching or compressing the dampers

until they are physically broken. The purpose of these tests was to see

if the specimens still met the acceptance levels established by 3M

Company after they had been through the cyclic tests. These tests were

performed on a manually controlled hydraulic testing machine with a

capacity of 200,000 pounds (Figs. 7, 8). The axial force and elongation

of the damper were recorded on an x-y recorder during the test. An

additional x-y recorder was used to monitor the rate of axial elongation

of the specimen. This rate of axial extension was held as close as

possible to 0.5 inches per minute. Half of the specimens from the

standard statistical tests were broken in tension and half were broken

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166 NISTNCSTAR 1-1A, WTC Investigation
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in compression. All of the specimens from the endurance tests were

broken in tension, .'he grips for these tests used 1 inch diameter A^90

bolts in single shear at one end of the specimen and 7/8 inch diameter

A325 bolts in double shear at the other end. From the recorded results

statistical information on the ultimate loads and the ultimate extensions

of the dampers has been obtained.

III. Results of Tests

A. Standard Statistical Tests

The major portion of this test program was devoted to

measuring some basic mechanical properties of the damping units. The

damping unit 'properties that were obtained are their loss factor, dynamic

stiffness, ultimate load, and ultimate extension. The amount of energy

dissipated p*>r cycle by the dampers and the amplitude of the periodic

displacement between the ends of the damping units was also measured.

Statistical distribution curves for the dynamic stiffness, loss factor,

energy absorbed per cycle and the amplitude of the periodic displacement

are given in Figures 9, 10, 11 and 12. The results of the ultimate

load tests are discussed in Section III-C. For sake of comparison,

results of tests conducted by 3M Company are included in the same figures.

The data used for the statistical information of thiG investigation

was taken from measurements made during the tenth cycle of oscillation.

Hysteresis loops recorded during first and second cycles were usually

not closed, and therefore, data from these first two cycles is not as

accurate as data from the tenth cycle. Also, since it is quite probable

that oscillation of the Trade Center Towers will occur in groups of

several cycles (this is typical of narrow band random vibration), ve feel

that the tenth cycle information is more meaningful. The results of tests

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NISTNCSTAR 1-1A, WTC Investigation 167
Appendix B

conducted by 3M Company were taken from tables in Reference 1. For

the dampers they tested, we plotted the results corresponding to the

first test on each individual damper that was tested at an ambient

temperature of 75°F 3° F. Nineteen of their tests fell in this

category.

The mean value and the standard deviation for each of the

damper properties are listed along with their distribution curves.

The most important single parameter is W the energy loss per cycle.

In our opinion the average value W - 57 1* inch. lbs. (with a standard

deviation of 72 inch, lbs.) is satisfactory for the proposed application.

It may be noted that the mean values of dynamic stiffness and loss factor

that ve measured {i.e., 555 kips/inch and 0.836 respectively) are above

the levels (^00 kips/inch and 0.7 respectively) stated in the Qualification Requirements [3j. The spread of the distributions about the mean

is quite large. In the case of the loss factor the standard deviation

(0.l68) is sufficiently large that had these dampers been representative

of the Bamples used to determine Acceptance (3) there is a good chance

that the initial sample would not meet the manufacturing control limit

for loss factor.

As was mentioned earlier, the output sipnal from a thermocouple

imbedded in the viscoelastic material was also recorded. The results

of tms measurement unfortunately were usually somewhat erratic. Some

temperature data did make sense insofar as it showed a gradual increase

in the temperature of the viscoelastic layer as the test progressed (see

for example the records of damping specimen No. 19 included in Appendix B),

In general, however, most of the records were not useful. The reason

for this may be that some of the thermocouples were in actual physical

contact with the metal of the damping units, whereas others were not.

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168 NISTNCSTAR 1-1A, WTC Investigation
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Originally we had planned to run the 101st and 102nd cycle of the standard test after the thermocouple indicated that the specimen had returned

to room temperature. Because of the difficulties with the thermocouple

we decided to let the specimen recover for twenty minutes, before running

the last tvo cycles. Twenty minutes was chosen because It was the

approximate duration of the first 100 cycles of the test.

All of the thermocouple records displayed a periodic pattern.

They show that the viscoelastic layer both heats up and cools down once

during each full cycle of oscillation. Tnis behavior was at first rather

surprising. We expected that the record vould show two peaks per cycle

instead of Just one. Two peaks would occur if the viscoelastic layer

could not tell a positive shear from a negative shear. The probable

explanation for the observed behavior is that the viscoelastic material

is anisotropic - i.e., its nroperties are a function of direction.

Figure 13 shows how the properties of a typical damping unit

change during a standard test. In general the stiffness of the element

tends to decrease while the energy dissipated per cycle, the loss tangent,

and amplitude of displacement all tend to increase. After a 20 minute

rest (cycles 101 and 102} the element properties have shown a recovery in

the direction of their original values. We computed the average fatigue

loss between the 10th and 100th cycles of the standard tests and found it

to be about 11%. The fatigue loss is the percentage change in the loss

modulus G". it is also equal to the percentage change in W/6 where W

is the energy loss per cycle and <5 is the elongation amplitude.

From bending moment measurements made while testing specimen No. 1,

the energy dissipation due to rotational motion of the damper was calculated to be about 19% of the dissipation due to axial motion.

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NISTNCSTAR 1-1A, WTC Investigation 169
Appendix B

The effect of misaligning the damper specimen in the test frame

vas also investigated. Misalignments of the order of 1/h inch, so

that the dampers can be easily pushed into place by hand, appear to have

a negligible affect on the amount of energy which the dampers absorb.

For the benefit of future users of the test frame, a sample of

the data reduction for a standard test has been included in Appendix B.

D. Special Cycling Tests

Four different endurance tests were conducted. Two of

these tests were run with an equivalent amplitude of 10 mils, and two

vere run with an equivalent amplitude of 19 mils. The results of a

low amplitude test are shown in Figure Ik. As can be seen, the properties of the damping element did not change appreciably in the course of

10,000 cycles. The properties did fluctuate somewhat, but this was

probably due to small changes in the ambient temperature. During the

second low amplitude endurance test, the frequency of oscillation was

increased so that the total rate of energy dissipation would be about

the same as it was during the high amplitude endurance tests. Even

after this higher rate of energy dissipation the specimen did not appear

to be damaged.

The results of a high amplitude (19 mils equivalent amplitude)

endurance test are shown in Figure 15. These results show that there

is some definite damage to the damper at about the 1000th cycle. This

test was probably too severe. SHCR estimate that on the average there

will be only 15 cycles a year with amplitudes greater or equal to to

amplitude used in this test. Furthermore, the test frame used in these

tests tends to overstretch the damper when it 6oftens (see Appendix A).

For the above reasons it appears that chances of fatigue failure of the

dampers are unlikely.

170 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

All of the tests conducted for this report were made with the

assembly bolts of the dampers in a finder tight condition. After the

element mentioned above had fatigued, we found that tightening the

assembly bolts seemed to restore some of the life of elements. Also, we

found that if the assembly bolts were only finger tight before the

element was bolted into the test frame, then vibration caused by the

impact wrench completely loosened them. For these reasons we highly

recommend that the assembly bolts of the damping units be kept tightened

at all times. We also checked to see if tightening the assembly bolts

affected the amount of energy dissipated by the dampers, and found that

tightening them decreased the energy dissipated about 10%.

The preload tests indicated that forcing the dampers to oscillate

about a nonzero mean displacement does not appear to reduce their

effectiveness. The average energy dissipated during the 10th cycle of

the preload tests was 5^1 in. lbs., whereas the average energy dissipated

during the 10th cycle of a standard test was 57 1* in. lbs.

Figure 16 shows the results of a typical high frequency test. The

overall results of the high frequency tests demonstrate that intermediate

oscillations at higher frequencies do not appear to change the effectiveness of the dampers at the standard frequency of 0.1 Hz.

Besides the tests discussed above, a few other tests were performed.

One series of tests that is of some interest is a set of three 100 cycle

tests at an equivalent amplitude of 23 mils on damping unit No. 3. At

the end of the third test some definite changes in the damper properties

were noticed. The results of these tests are included in Appendix C.

C. Ultimate Load Tests

The results of a typical ultimate load test are shown in

Figures 17 and 18. The curves which are shown are for an element that

NISTNCSTAR 1-1 A, WTC Investigation 171
Appendix B

vas tested in tension. Two peaks appear in the lo»d-elongation curve

(Fig. 17) because after one side of the element separated the other

aide continued to load for a vhile longer. The displacement vs. time

curve (Fig. 18) shows that the rate of elongation was quite close to the

desired 0.5 inch per minute.

Statistical distribution curves for the ultimate loads and

ultimate extensions of dampers from the standard statistical tests are

shown in Figures 19 and 20. The results of 13 tests conducted by 3M

Company and reported in Reference 1 are also shown.

It may be noted that the average ultimate load (1*7.7 kips) that

we measured is greater than the value (1*5 kips) stated in the Qualification Requirements 1 3). The spread of the distribution is quite large.

The standard deviation (9.3 kips) is sufficiently large that had these

dampers been representative of the samples used to determine Acceptance (3}

there is a good chance that the initial sample would not meet the

manufacturing control limit for ultimate shear strength. In our tests

half of the units were broken in tension and half were broken in compression.

The average ultimate load for the tension units only vas 51-0 kips and

the average ultimate load for the compression units only was kk.h kips.

The average for both tension and compression was 1*7.7 kips.

The most common mode of failure for the specimen was separation

at the bond between the metal and the viscoelastic material. All of the

elements that were tested in tension, and about half of the elements

tested in compression, failed in this manner. Another mode of failure

that occurred during the compression tests vas for the viscoelastic bond

to break on one side of the element and then for the other side of the

element to buckle (Fig. 21). Only one element that was tested buckled

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172 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

on both sides. The buckling and the breaking of the viscoelastic

bonds vere the only modes of failure that occurred.

Ultimate load tests were also conducted on the elements from

the endurance test. The tvo elements from the low amolitude (10 mils

equivalent amplitude) endurance tests both broke at loads that were

slightly higher than the average ultimate load of 1*7,700 lbs. However,

the two elements from the high amplitude (19 mils equivalent amplitude)

endurance tests broke at loads of 22,000 lbs. and lU,000 lbs. which is

considerably lower than average. This further verifies that prolonged

cycling of the damping units at high amplitudes does result in

permanent damage.

IV. Conclusions

The most important characteristic of the damping elements is

their capacity to absorb energy under oscillations at amplitudes and

frequencies which are probable for the World Trade Center Towers.

Ideally they should absorb adequate energy no matter when the oscillations

occur or what the ambient conditions are during the oscillations. In

our tests we have not been able to cover all possible operating conditions

but we have shown that this particular batch of elements do absorb an

average of W = 57 1* inch-lbs under standard test conditions with respect

to amolitude, frequency and temperature. Furthermore, the energy

absorbtion is not significantly impaired by modest variations in amplitude,

frequency and temperature.

Our major concern in the beginning centered around the endurance

capability of the elements. We found that the elements could withstand

10,000 cycles of 10 mils equivalent amplitude with no indication of

permanent damage. At large equivalent amplitudes (19 and 23 mils) we did

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NISTNCSTAR 1-1 A, WTC Investigation 173
Appendix B

obtain evidence that prolonged cycling caused a growing breakdown of

the bond betveen the viscoelastic material and the steel vhich vas

reflected by a reduction of the element's stiffness and its ultimate

load capacity. See data for Specimens No. 3, No. h and No. 5. In

spite of the alteration of properties which occurs we conclude that the

units will provide adequate energy absorbtion for at least 1000 cycles

of 19 mils eauivalent amplitude at temperatures in the vicinity of

?5°F. When the ambient temperature is in the vicinity of 85°F the bond

breakdown is apparently accelerated somewhat. At this temperature

(see Appendix D) it appears that the units will provide adequate energy

absorbtion for 500 cycles of 19 mils equivalent amplitude. If present

estimates of the number of large oscillations to be expected are not

excessively optimistic, it does not appear that there is any real danger

of a loss in element effectiveness due simply to the accumulation of

cycles of oscillation.

An unknown factor is the effect of aging on the viscoelastic

elements. Our tests were completed within a six month period. We had

no opportunity to observe any long time deterioration of the elements.

Another unknown factor is the effect of extreme heat or extreme

cold on the viscoelastic elements.

When the elements are installed in the towers it is essential

that the bolts be tightened meticuluosly . Any slip in the Joints would

vitiate the usefulness of the dampers. Careful alignment of the element

attachment points should be maintained. Our tests indicated that up

to 1/h" of misalignment did not affect the energy absorbtion capability

of the element. We recommend that the element assembly bolts be tightened

with a small hand wrench after installation rather than being left

finger-tight. This may decrease the energy absorbed by the element in

small amplitude cycles by up to 10 percent but it will serve to protect

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174 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

the element against deterioration under large amplitude cycles.

Because of the wide spread in damper properties from batch to

batch and from unit to unit within a batch, it is suggested that a

program of testing sample units be instituted to check on element

parameter values as the various batches are delivered. The most

important single parameter is the energy dissipated in a cycle of 10

seconds duration under a known equivalent amplitude. It is this

parameter which is directly proportional to the increase in overall

tower damping ratio provided by the damping unit. It would be desirable

if W, the energy loss per cycle, for 19 mils equivalent amplitude was

never less than ^00 inch lbs. A desirable average value of W for all

batches would be 575 inch lbs. (i.e., about the same as that of the

batch reported on here).

V. Suggestions for Further Testing

A program of periodic testing of random samples of installed

elements and of the stored unused elements should be instituted. All

the endurance tests performed so far have been accelerated life tests.

The effect of the passage of years on used or unused elements is still

an unknown factor.

The calcualted effectiveness of the dampers depends on the

magnitude of the local frame stiffness almost as much as it does on the

aamping unit parameters. If the local frame stiffness were only

200 kips/inch instead of the design value of 600 kips/inch (as was the case

for the test frame) the energy absorbed by the damper would only be

one-fourth of that predicted. In the case of the test-frame this was

compensated for by using a larger eccentric. In the actual towers no

such compensation is possible. Therefore, it seems imperative to check

-18-

NIST NCSTAR 1-1 A. WTC Investigation 175
Appendix B

the actual stiffness of the local frame at a few typical damping element

locations as soon as possible. If the actual frame stiffness is

significantly smaller than the design stiffness the damping units would

have to be redesigned. To measure the local frame stiffness one could

substitute a turnbuckle and a forcegage for the damping unit and then

use the LVDT from the test frame to measure the contraction as the

turnbuckle was tightened.

There are a number of tests which would be very interesting to

the profession and which would be useful for the benefit of future

designers. These are listed below in the order of their desirability.

1) The natural frequencies, damping ratios and mode shapes of

the towers should be measured. These can be measured in a few days

time by simultaneously recording the outputs of two sensitive seisometers

placed at various locations in the buildings and then digitally processing

the tapes. Such a service is available fj-om the Structural Sciences

Division of Earth Sciences {A Teledyne Company). See literature in

Appendix E. The damper oscillation has been designed on the basis of a

natural mode and natural frequency computed during the early design of

the building and on the basis of an educated guess as to the inherent

damping of the towers. A comparison with the measured values would be

very informative.

2) Permanent recorders should be installed near the tops of

both buildings to monitor the motions (acceleration levels) throughout

a period of several years. This would provide valuable feedback for the

elaborate wind tunnel and statistical studies which were employed to

arrive at the levels of motion used in the design of the damper installation. This would also give the building owner increasing confidence in

the sway resistance of his building (if the design is in fact successful

and the motion amplitudes remain small).

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176 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

There are slow speed tape recorders vhich go continuously and

only need to have the tape changed once every three months , and there

are other instruments like strong motion seismographs vhich remain

inactive most of the time and only begin to record vhen a certain

threshold level is reached. See Appendix E for literature.

3) One or two damping units in the tovers could be modified

so that they could provide force and motion signals at the damper

vhich could be compared vith the tower motion. In the simplest modification all that would be necessary would be to replace the pair of angle

irons running from the element to truss by the instrumented angle irons

from the test frame. The force and elongation signals would provide

energy loss loops vhich permit an estimation of how much damping the

viscoelastic units were actually providing. These results would be even

more meaningful if the local building frame stiffness had been verified

in situ vith a turnbuckle as described above.

NISTNCSTAR 1-1 A, WTC Investigation

-20-

177
Appendix B

References:

X. SHCR Report No. DU-1, The World Trade Center Vi3coelastic Damping;

Units , July 17, 1967.

2. Specification for Structural Joints Using ASTM A325 or AU90 Bolts.

Approved by Research Council on Riveted and Bolted Structural Joints

of the Engineering Foundation, September 1, 1966. Endorsed by

American Institute of Steel Construction, Inc. Endorsed by

Industrial Fasteners Institute.

3. Technical Specifications for Visco-El'astic Damping Units for

the World Trade Center, 3786.

178

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NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

S K I LLIN 6 - HELLE-CHRISTIANSEN - ROBE RTS O N

August 29. 1968

Mr. Kalcoln P. Levy

Port of Hew York Authority

World Trade Center Planning

111 Eighth Avenue

Kev York, New Tork 10011

Bcf ertmea: The Uorld Traiio nontax

MIT Test Prop.rass

Dear Mali

On the efteroocn of August 2E, 1968, tha writer visited HIT to exaaina

the dacping unit test rig and to evaluate progress to data.

First, In response to inquiries fron MIT, the writer trsnsnitted the

following information:

1. All high-tensile boltc trust bo tightened usiisg the trum-of- 1 henut technique.

2. For 1

M ASTM A490 boltn, required torque could be 1AO0 ft-lba or

higher.

3. Washer rcquiroreonts for ASTlt A323 high-tensile bolts are tfi follows:

c. With bolec 1/16" larger than the nominal bolt di-tmeter, no

waniiors are required.

b. For all other caaee, 7/16" thick plate washer* sr*e required

under both bolt head and cut.

NISTNCSTAR 1-1A, WTC Investigation 179
Appendix B

SKILLING — HELLE-CHRtSTlANSEN - ROBE RTS O N

Kr. Malcoia P. Levy 2 August 20, 1568

A. Washer requirements for ASTN A490 high- tensile bolts are as follows:

a. Kith holes not core than 1/H" larger than the nominal bolt

disaster, standard hard«rv*4 vaohera are required und*r Loth

bolt head and nut.

b. For all other cases, 1/2" thick plate waahare ere required

under both bolt head and nut.

This information vrb given to Rr» Larry Vittig, aa Professor Cranial 1 vas not expected in the laboratory for th* remainder of tht week.

Kext, the equipment was examined and the following consent submitted to

Mr. Vittigt

1. The quality of welding varies fro* roor to Inexcusable. Every

defect known to the writer and detectable by casual visual

•uucioaiiuu « n« itronu in prpfuijon. since stress levels era very

low, the quality of voiding My not adversely affect test

results. Still, the writer recoananded that key welds be cleaned

by wire brush and examined from tiao to time throughout the test

program.

2. The device intended to provide transverse stability is totally

inadequate if stiffness in the transverse direction is required.

Suitable techniques for improving the transverse stiffness vera

proposed, should remedies be required.

3. Too basic geometry of the "trusses" is far frcm ideal. Tho

writer pointed out eccentricities which should affect truss

stiffness by a substantial uargin. Such eccentricities, of

course, will not exi3t in the building construction.

A. The lack of ndeouate stiffness in the teet franc was discussed.

The ir.tri>duct.iun ol flange beudir.g, the effects of ntrcos

concentration and the like, and the of recta of the quality of

welds (see 1. above) or. the behavior of the fratse vera discussed

in some detail,

5. Mr. Vittig pointed out ttuat the drive bearing, lacked the

capability to resist side thruot and that his repeated efforts

had been unsuccessful in preventing the drift of the bearing.

This drift results In a sudden impact on the test rig, causing

transverse oscillation and rendering the rig useless. Mr. Wittig

etated that ha was prepared to order a nov bearing and that

delivery of such bearing should be occompliehed within a week.

180 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

SKI LLING - HELLE-CHRISTIANSEN - ROBERTSON

Kr. Mslcolm P. lavy 3 Aui^iat 25, 1968

6. It vu noted that bolt »ic»o Jo not alv-aya compare to tha

requirements sbovn in tho Orovinn*, Kr . wicvig pointed out that

AISC valuta for the laaacr bolts Indicate that bolt slip ahould

not occur. Tha writer pointed out the etatletical belwavior of

ouch bolts, the difficulty in measuring tjJTp detecting bolt slip

and the nocaseicy of preventing such nllp. - a

It was observed that no meaningful vork had been acccmplialied or vould bo

accomplished for at least a week or two. Mr. VittJg stated that he vould

be returning to regular classroom vork *t the end of the third veek in

September, '-"hen the writer pointed out that the teat work vould still be

under war, Mr. Wittig indicated that he intends to concimi* his participation In the test program and that additional help could ba obtained.

It is the writer's opinion, not expreased to Kr. Wittig. that it is

unlikely that any useful testins vill be accomplished within tha next

three or four weeks.

Other than as expressed above, tho writer found the cquipnent to be sound

and of cood dealers. Probably nore important, Mr. Wittig appear* to be

dedicated inc reacurceful.

It is the vritor's opinion that ouch of the original Intact of the test

program may be lost because of deficiencies in the tost equipment.

Specifically, the writer doubts that the assembly vill adequately

duplicate conditions as they will exist in the building. Still, with all

of its defects, the equipment may be substantially closer to such n

eixtulation than was accomplished by the program conducted by 3il under the

auperviaion of ShCR.

Very truly yours,

SK1LLINC, I1ZLLE. CHRISTIAUS^, ROUEHISOIi

Leslie E. ilobafcEtiuii

LER:e

cc: Kr. Lcntcr Fcld, PKYA

Ihr. Stephen Crancell,

Ur. Larry Vittig, >tIT

NISTNCSTAR 1-1A. WTC Investigation 181
Appendix B

SKILLIN6, HELLE, CHRISTIANSEN, ROBERTSON

Consulting Structural and Cni? Engineers • 230 Part Avenue, New York. N. Y. 10017 • Mu. 9-SS7-?

John B. Sir/Wing " Hclge ). Relic • ]ohn V, Chrijfianjcn * Lexh'e E. Rofcerfcon

Wayne A. Bicker Comuhond

May 22, 1969 fewtf F. JurJtwn

Port of New York Authority

World Trade Center Planning

111 Eighth Avenue

New York, New York 10011

Attention: Mr. Malcoim r. Levy

Reference: The World Trade Center

Damping Units

We have reviewed the report, "Test of Viscoelastic Damping Units for World

Trade Center Tower Buildings", by S. H. Crandall and L. E. Wittig, dated

April 23, 1969. This is an excellent report confirming in a general way

the test results obtained by SHCR-3M. Also, this report gives additional

data which are relevant to an evaluation of the performance of the damping

units in the system environment of the intended installation.

From the photographs of the specimens in Figures 8 and 21, we surmise that

an additional bolt hole was made at M.I.T. in the structural bar of each

specimen to fit the test jig of the ultimate strength test. This additional

hole overlaps the original bolt hole. The overlapping holes probably' would

not influence the strength so long as the forces are transmitted :by •friction.

Should a major slip of the bolts occur, there is no doubt that the overlapping

hole will affect the ultimate strength either in tension or compression. In appendix C, the ultimate strength of Specimens No. 14 and No. 16 were recorded

as 49,000 lbs. and 48,000 lbs., respectively, whereas the corresponding

Force-Elongation curves indicate maximum forces of 57,000 lbs. and 38,500 lbs.,

respectively. The reason for the discrepancy is not clear to us. In any case,

the conclusions of the report arc not affected by these two comments.

We would like to note that the Ultimate Strength in compression and in tension

of this test series has a mean value of 47.7 kips with a standard deviation of

fcoacist «. il«vi*h *• OaTaa

««I>T a. OOtlKI CM t»« » r T. u» JOCTCIM MI*

V. A. fllllOIII

WILLIAM O. WAACI atCKAKO t. T»»i.O« LOacnt* v K. j. whit t . j a . »t*»tv« •» » »c t «

i • * o wntniMOTOft a u i i t> i m « . t t a t t i t . w*»h, notch aaiot

182 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

SKILLIN6, HELLE, CHRISTIANS EN, ROBERTSON

Port of New York Authority

Attention: Mr. Malcolm P. Levy - 2 - May 22, 1969

9.3 kips ami that this combination of values would have failed to meet the

Acceptance Requirements proposed in our letter dated May 2, 1969. The

results of the compression tests conducted by 3M Company had a mean of 54.1

kips with a Htandord deviation of 4.5 kips and these valucB would meet the

proposed requirement of mean Ultimate Strength 45.0 +1.5 (S.D.) kips in

compression. This comment should be considered prior to forwarding copies

of this document to 3M for their use. Also, when conditions will permit,

it is important that a copy be forwarded to 3M as this information cannot

help but assist 3M in meeting their contractual commitments.

While we concur with most of the conclusions stated in Section IV of the

report, it is clear that Messrs. Crandall and Wittig are not structural

engineers, as their suggestions are not wholly practical. We wish to comment

on thi6 section as follows:

L. The program of periodic testing of random samples, uf the ir.c t; -lied

and of the 6tored unused dampers has long been in the test program

for VTTC and was discussed both at MIT and at Mr. Kyle's office.

2. It is neither necesBary nor practical to test' the ilocal frame

stiffness as proposed in this report. It is not practical because

of the structural interconnection of column-to-coluan and of trussto-truss through the structural ties of spandrel, bridging and slab.

It is not necessary as the column stiffness plays only a minor role

in the system and because the truss stiffness can be calculated

with considerable accuracy. Previous calculations for uniformly

loaded trusses have been verified through load testing of actual

trusses. In short, the only way to perform this test requires that

many trusses be loaded simultaneously Cas would occur in the real

building) or else a structural separation must be provided around

a single truss by cutting both the slab and the bridging - this

latter technique should not be considered. We do not feel that

the cost of this proposed test is warranted.

3. Additional tests arc cited which would be of interest to the

profession. In this regard, we have two thoughts:

a) SHCR is preparing a paper to be delivered before the ASCE,

or similar organization, discussing the use of such dampers

in building construction and presenting a method of analysis

for such dampers. The paper will, of course, be presented to PNYA for its review in the light of any impact it may have on

the rentability or other facet of The World Trade Center.

b) SHCR, with PNYA concurrence, has contacted A1SC with the view

of obtaining technical and/or financial assistance in the

performance of post-construction testing. SHCR will, of course, pursue this question further with AISC in the months ahead.

NISTNCSTAR 1-1 A, WTC Investigation 183
Appendix B

SKILLIN6 - HELLE-C HRISTIAN SEN - ROBERTSON

Port of Kew York Authority

Attention: Mr. Malcolm P. Levy -3- May 22, 1969

We note that our copy of this report does not include Appendix £. We assume that other omissions, if any, have no bearing on the conclusions

of the report.

We will report to you further as our proposals for additional testing

become solidified. In the interim, should you have further questions,

do not hesitate to call.

Very truly yours,

SHILLING, HELLE, CHRISTA1NSEN , ROBERTSON

Leslie E. Robertson

cc: Messrs. L. S. Feld, PNYA

J. M. Kyle, PNYA

S. H. Crandall, MIT

L. E.Wittig, MIT

LER/ld

184 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

MASb-kCllU^JlTl* I>*»**iTUTK OJ' TCCUNOIOGY

J una 2, 1969

Mr, John M. Kyle, Chief Engineer

The Port of Mev York Authority

HI Eighth Avenue at 15th Street

New York, New York 10011

Dear Mr. Kyle:

This letter is written in response to the letter from Mr.

L« E. Sobertson of S11CR dated May 22, 1969, and addressed to Mr.

M. r; Licvy. In hi» Mtc&cr s5ii. nvuci\ovu: rslscs seas question? "* n connection with- our report Test of ViacoelaBtic Damping Units

for World Trade Center Tovcr Build lngs" by Crandall and Wittig,

Anril 23, 1969. I Bhall try to answer these questions.

.With regard to the ultimate tents the cxpionenuu an tnc

report is somewhat abbreviated. Let tnc give some rurtner details

here. The testing machine wc used had a large dial which indicated

the force applied to the specimen by a hydraulic drive. For static

and slow-speed testing, this force is read off point by point by

the operator. Since our race, of loading was fairly rapid we made

no attempt to obtain the force history from the dial*- Wo did,

however, record the maximum reading of this dial for. each tent

(this was facilitated by having the pointer drive a marker which

remained at che highest level). In order to record the force

history wc used acrain gages on the tent fixture. The p.ngcs for

the compromnion tout nre vlnihlo in Tlj\. ft of the report. )*or tl»«« tension tontn the tout fixture mn.lo win of the normnl holt Unlet* «f

the olowent «»uil w<m lour, intmt)*h f«» pr«»vl«h» inh»ijiint«» Icwi'.th for rh»» gnp.c ncctlon. In the CcnHioii t<*nc:i tltor«» wwt |».ood nftftwioimt (wlihla

ono or two kips) between the ultimate load registered on the tlJnl

of tho testing machine and the peak of the f orce-diftploccracnt curve

baaed on the strain gage signals. In the case of the compression

testa wc had to compromise on the length of the test fixture. Too

long a fixture would encourage buckling of the clement and too short

a fixture would compromiGC the strain gage test section. In order

to gain a little length wc moved the bolts a little closer by drilling an extra hole in tho clement as shown in Fig. 21. Note that

there is full bearing for che bolts for compress ivo loads. Jn the case of tho comprcaeion tcBta chore was mora diacrnpancy botvoon the

NISTNCSTAR 1-1 A, WTC Investigation 185
Appendix B

ultimate load registered on the dial of the testing machine

(this value Is noted at the bottom of figures such as Fig. 17)

and the peak of the force-displacement curve. The greatest discrepancies (specimens 14 and 16) occurred where compressive failure was accompanied "by large amounts of buckling. The sense of the

discrepancy was capos ite in these two cases.

Dur interpretation of this discrepancy is that because of the

short gage longth our strain gages (which were calibrated for

perfectly axial loading) are no lonp.cr correct when a large bending

moment is superposed. Vc, therefore, conaidered the machine dial

reading to provide the best estimate of the ultimate load in

these cases. The values given by the machine dial reading were used in constructing Fig. 1$ and in calculating the mean and

standard deviation.

We are in agreement with Mr. nobertson regarding most of his

comments with the one exception concerning the necessity and practicality of testing the local frame stiffness. We would like to repeat our recommendation thnt the local frnmo ntirfnonn bo eJi«ck#»«1

ob noon- mi-poBtialuu • 7m"* i"- rT-~-«".tri WTVC^;;; ^r ~tl;:t .^~^'T^"-4t^;,*. J;;jr^;—irrrr— cion_ could be. icopnrdizod hv inndectuate locol. frame ntlffnons.

Furthermore, it will T>o difficult if not impossible to assess cue performance of the system when it is in operation if the magnitude

of the local stiffness remains unknown.

We think that Mr. Robertson nas overestimated the difficulties

involved in making this measurement. We had been thinking in terms

ot one evening' a work. This was under the assumption that the major

contribution to the local stiffness was truly local. Mr. Ttobertaon

points out that tbere may be considerable diffusion of load from

truss to truss. This means chat instead of measuring only one load

and one deflection it will be necessary to measure one load and

a number (possibly 6 to 12) of deflections. This Is still an entirely reasonable proponition in terms of time and money.

In more detail what wo arc proponing is thnt aB »oon as n

tower has risen to the point where a floor which Is to have

dampers installed (end for which the design local stiffness has

been computed) is structurally complete the test would bo performed

by installing an instrumented turn- buckle, in the. damper location of one of the central trusses. The deflection measured by an l.VnT across this unit would be recorded as the tensile force wan raised

from zero up to 30 kips, say. The load would then he removed and

the LVTtT moved to the adjacent element location. Agnin the load

would ho put on and the doflection recorded to obtain the corresponding

ing influence coefficient. 'i1»o procn«iur« would Ii1w»« he r«p*>au«i«i.

186 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

The LV*>T would be moved Iron sc.it ion to station until the Influence

coefficient was no longer nessurablc. Using superposition and

this strt of influence coefficients it is a simple matter to predict

the deflection of the entire truax-nyHtens when loaded uniformly at

all the stations. If time is available it would be desirable to

repeat the entire tBcasurcwcnt at other "typical" locations

(e.g., on the sane floor but on other faces of the building).

Ideally this test should be performed vhen construction is not r.oing on (e.g., night shift, holiday) so as to r-iinimizc background noise..

X trust that these coosncnts will he helpful to you.

'Stephen II. Crandall

Professor of

Mechanical Engineering

SUCiarcc: Hr. Yontar

NISTNCSTAR 1-1 A, WTC Investigation 187
Appendix B

TABLE OF CONTENTS

Introduction

pf£c1

Testing Programs 2

Evaluation of the Prototypes 2

Conclusions 6

References 7

Appendices

1. Structural damping in buildings 9

2. Calculation ot critical damping ratio

contributed by viscoclastic damping

units and expected number of cycles

of oscillation for the damping units

exceeding given a»it)Ht-ii»lp; *f Hf?-

placotnent 16

3. Maximum force of the damping units

as a function of the dynamic stiffness 34

188 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

June 2, 1969 Page 1

THE WORLD TRADE CENTER

Report No. DU-3

VISCOELASTIC DAMPING UNITS

Introduction

The importance of the action of vind on tall buildings has been

generally recognized for many years. This action was traditionally

conceived and treated as static forces by the community of building

designers. However, measurements on existing buildings by various

investigators have shown that the responses of tall buildings to strong

vind are predominantly dynamic. More recently, the static and dynamic

responses of the twin towers of The World Trade Center were studied bv

means of static and acroelastic models in a micro-meteorological wind

tunnel [1]. The experiments showed that, for the wind directions critical

for the structural design, the deflections, and hence the. stresses, arc

primarily caused by dynamic oscillation of the building. It has been

established that the amplitudes of the oscillation are inversely

proportional to the square root of the critical damping ratio for lightly

damped buildings in turbulent vind.

The critical damping ratios Intrinsic in buildings were measured by

several researchers. A table of the data found in the literature is

Included in Appendix 1. Based on the reported data, it was estimated that

the intrinsic critical damping ratio of The World Trade Center towers is Bfor design against excessive stresses. In order to increase the

mechanical damping of the towers, viscoclastic damping units were developed

for installation in the floor system. These damping units have been

OKUUNO. HCLLt, CHRISTIANSEN. ROBERTSON

NIST NCSTAR 1-1A, WTC Investigation 189
Appendix B

June 2, 1569 ?*8C *

described previously in Report DU-1 [2]. Tr»c viucoclactic damping units

are expected to increase the building damping from to VBB which

was assumed in tlie structural design o£ the towers. The contribution cx

the damping units to building damping was calculated in Report DU-1 and

is further summarized in- Appendix 2. The expected number of cycles of

oscillation per year is also given in Appendix 2 for the damping units

having amplitudes of deformation exceeding given amounts.

Testing Programs

Two testing prn»r5=:s hsvc b«cu carried out for the prototypes of the

viscoclastic damping units. In Program I, twenty-two prototypes of the

doping units were tested by Minnesota Mining and Manufacturing Company

(3M Company) in May 1967 [2). In Program II, thirty-nine prototypes were

tested at M.I.T. by Dr. S. H. Crandall and Mr. L. £. Wittig in 1969 {3] . Whereas the prototypes in Program I are subjected to cyclical axial

deformation In the form of a sine function at 0.1 Hz with constant

amplitude of 0.020 inch, Program II attempts to simulate the system

environment of the intended installation which consists of the exterior

column, the viscoclastic damping unit, and the floor truss system.

The testing conditions of the two programs are compared in Table 1.

The results of the standard tests are compared in Table 2.

Evaluation of the Prototypes

The specimens in Test Program I have dynamic stiffnesses which have a. higher mean value and a higher coefficient of variation than those in Test

j 90 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

June 2, 1969 Page 3

TABLE 1

COMPARISON OF TUO TESTING PROGRAMS

1. Number of specimens

2. Displacement - time function

3. Displacement amplitude

4. Rotational notion

5. Standard test

6. Endurance test

7. Frequency of cycling

8. Mean displacement

9. Room temperature

10. Frame stiffness

11. Rate of loading for

Ultimate Strength Test

PROGRAM I

22 Sinusoidal

0.020" constant amplitude measured across viscoclastlc slab.

No

100 cycles at 0.1 Hz and at 0.020" amplitude , then an extra

cycle when temperature of 5CO?lastic

slab returns to the room temperature.

1000 cycles at 0.020"

amplitude.

0.1 Hz None

75 t 5°F with IS tests at 75 1 3°F. Not applicable.

Not reported. All

bolts in double shear.

PROGRAM II

39 Sinusoidal

Variable, measured ocropc

damper scat and damper ex- tension. Constant equivalent amplitude of 0.010",

0.019", or 0.023", if damper is replaced by an clastic rod of axial stiff- ness equal to 600 kips inch. Yes. Caused by vertical

motion of one end of test

100 cycles at 0.1 H2 and

at cquiv. amplitude of

G.CIs", two extra cycles

after a rest of 20 minutes

?~c- tenpersture it * — — w * <

10,000 cycles at equiv. am- plitude of 0.010";

2,600 cycles at equiv. am- plitude of 0.019"

0.1 Hz, 0.25 Hz, 0.50 Hz Zero for standard tests. Special tests at mean displacements of +0.011",

-0.0125", +0.023", and

-0.021".

75 t 3°F. One special

test at 85°F.

192 kips/inch (computed

stiffness at 47th Floor

is 600 kips/ inch)

.

0.50 inch/minute (approx.)

Bolted connections same as In design for field installation.

NISTNCSTAR 1-1 A, WTC Investigation 191
Appendix B

June 2, 1969 Page *

TABLE 2

COMPARISON OF RESULTS OF TWO TESTING PROGRAMS

STANDARD TESTS PROGRAM I PROGRAM 11

1. Dynamic Stiffness (kip/inch)

Mean 825 555

Standard deviation 122 62

Coefficient of variation 0.15 0.11

2. Loss Tangent

Mean 1.38 0.84

Standard deviation 0.18 0.17

Coefficient of variation 0.13 0.20

3. Ultimate Strength (kips) Compression Comptession Tension All

Mean 55.0 45.0 50.4 47.7

Standard deviation 3.1 4.9 10.6 9.3

Coefficient of variation 0.06 0.11 0.21 0.1

192 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

June 2, 1969 Page 5

Program II. The differences can be attributed to the greater scatter

cf test temperatures, to the slightly lower mean value of the test

temperatures (73.7°K) and to the use of several different formulations

cf the viscoclastic material in Test Program I. The damping units of

Program 11 have a mean dynamic stiffness of 555 kips per inch at 75°F,

vhich is very close to the optimun value of Mkips per inch. At the

tame time the coefficient of variation equal to 0.11 is very satisfactory.

The specimens in Test Program 1 have a mean loss tangent of 1.38

vhich is much better than the design minimum mean of 0.70. Futhermorc,

the specimens arc quite uniform in the loss tangent with a coefficient

of variation equal to 0.13. The specimens in Test Program 11 have a

mean loss tanernr «f f».*£ v»ith £ coefficient cf variation of C.2C.

This is satisfactory, since the mean loss tangent of the universe

represented by these specimens would be greater than 0.77 with a

probability of 0.95 according to the t-Distribution.

The ultimate 6trength obtained in Test Program 1 has a mean of 55,0

kips and a coefficient of variation of 0.06, which indicated high strength

and good uniformity. If the dynamic stiffness of the damping unit, K^,

remains below the design value of MB kips per inch, the maximum design

foTcc in the damping unit, F^ would not exceed 34 kips (Appendix 3). tf

reaches 900 kips per inch, maximum F^ would reach 40.9 kips. In such

a case, about 20Z of the damping units represented by Test Program II

vould be near or over the breaking point. The reasons for this discrepancy

of ultimate strength between the two test programs are not clear. Perhaps,

the difference in the test Jigs is the source of the discrepancy. Fortunately,

the results of Test Program 11 indicate some positive correlation between

NISTNCSTAR 1-1A, WTC Investigation 193
Appendix B

June 2, 1969 Page 6

dynamic stiffness and ultimate strength. In fact, the coefficient of

correlation between these tvo parameters is +0.42. This means that the

damping units whicu have low ultimate strength tend to have low dynamic

stiffness also. Since maximum force in the damping unit decreases with

decreasing dynamic stiffness, the probability of breakage of the damping

units under the maximum design wind condition is small if the results

of Test Program 11 are representative of the production units.

hi m mammm* m i

The special tests of Program II indicate that the damping units are

boi.it.Ttici.ox7 with respect to fatigue, to higher trcquencies ot osculation

find to a temperature HAp of 10°F score ?5°F.

Conclusions

The two test programs of the prototypes indicate that the damping

units in the floor system will provide an expected increase of WtKB in

the critical damping ratio of The World Trade Center towers.

9m

194 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

June 2, 1969 Page 7

References

1. The World Trade Center Kind Re port, Final Chapter, July, 1966, by

Vorthington, Shilling, Hcllc, & Jackson, Consulting Engineers,

New York, M. Y. (now Skilling, Hcllc, Christiansen, Robertson).

2. Viscoclastic Damping Units , Report No. DU-1, The World Trade

Center, July 17, 1967, by Skilling, Hcllc, Christinnsen , Robertson,

Consulting Engineers, New York, H. Y.

3» Test of Viscoclastic Damping Units for World Trade Center Tower

Buildings , April 23, 1969, a report to The Port of N<>w York

Authority by S. H. Crandall and L. E. Wittig.

NISTNCSTAR 1-1A, WTC Investigation 195
Appendix B

\^l\Xi%' 11,1 f*t)KI (>1 MV\ Y<»KK AUlilOKIiV

w i .. :.i i i.i. t !< p.iiinifiu

November 5, 1«>?1

Minnesota Mining A Manufacturing Corp.

3M Center

St. Pavl, Minnccnt. IStm

Attention: Mr. Don Caldwell

Re: THE WO". LD TRADE CENTER - CONTRACT WTC-22<..00 - TESTING OF 12 DAKP1NC UNITS REMOVED FROM

FLOORS 2b, 27, 2<> & 30 - TOWER A

Gentlemen:

This will confirm oral information given to you by our

Mr. Fetd on 11 A/71:

3M is to perform an equivalent Acceptance Test series on

the subject group of units (see Schedule XI attached). These units

were all installed in November of 1970 and remained in place for

the past year In unheated space throughout a "cold" winter. We are attempting to ascertain if Ihv uiitt» have actually been affected

by the "cold" and are in fact capable of passing an equivalent

acceptance test. The number and sequence of testing for loss factor

and stiffness, fatigue loss and ultimate strength are to be determined

by JM.

V.'i ws»!.j appreciate yctsr «-xp*t§5 * *•>-• »hu ,,,i es D f t cs ts upon receipt of the units. All work is to b* performed unri< r the

unit prii< provKion^ for «ivtln>- under the sul. )• i t ij,ntrai 1. Pleas* advi--€ thi>- "ffii> a- to your testing ••thtrtule.

S i m <• r i 1 y ,

i

t

'

. r. >

1 A * ' ->

M.. 1. .. l/ V. 1 < vv

M« s-rs. W. Borl.m.l. I). Rr wn, I \y,/-.t Mil U \ t

-

, < »m*> f mh h > t t . > .. u •

I. Wlii i. ( i)H K ), r. Wirm k» - all w/att.

196 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

CONTRACT WTC-221.00

WORLD TRADE CENTER

THE PORT OF NEW YORK AUTHORITY

LACLEDE CONTRACT 67 -J -3 1301

Coordinator of Construction

The World Trade Center

The Port of New York Authority

111 Eighth Avenue

New York, New York 10011

DATE

TRANSMITTAL LETTER NO . 10

TRANSMITTAL OF FLEXH?J\L TESTS

Transnitted herewith is one copy each of the sequentially numbered

flexural test reports listed below. Submission is in accordance

with the sixth paragraph of Paragraph 105.102 "Resistance Welding"

of our Contract WTC-221.00.

Flexurai Test

No. Date of Test

23 12/17/68

2- 12/17/68

25 12/17/68

26 12/19/68

27 12/m/68

26 12/31/68

2 5 12/31/68

30 1/ 7/6q

31 1/ 7/69

32 1/ 7/69

33 1/2V69

3^ 1/24/69

/

For .€m>t^ripkL

CC-.'Mr. James White Robert D. tiaf

Skilling-Hclle-Christiansen-Robertson Director of Technical Services

2 30 Park Avenue

New York, New York 10017

Mr. A 1 Guttenta^, Project Engineer

Tishunan Realty & Construction Co., Inc.

30 Church Street - 11th Floor

New York, New York 10007

(COPY NOT SENT)

NIST NCSTAR 1-1 A, WTC Investigation 197
Appendix B

May 15, 1969

R. D. BAY

RE: WTC-221.00

FLEXURAL TESTS

SHIPMENT NO . 2

The results of all Flexural Tests performed for Shipment No.

2 are shown on the attached sheet 1 of 2 dated May 15, 1969.

This sheet shows the comparative deflections for incremental

loads of 500 lbs. for each truss tested. Sheet 2 of 2 gives

the backup data for Sheet 1.

David B. Neptune

IP

198 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

WORLD TRADE CEtfTBR May 15, 1969 FLEXURAL TESTS Page 1 of 2 KOS. 23 THRU UP Conparative Deflections in inches for Incremental Target Loads of 500 Pounds m (2)

[ (3) (4)

TRUSS

IfiRK MO.

| TEST

! 80.

DESIGN DSFL

In.

DESIGN LOAD

Pcf

TARGET LOAD IN POUNDS (5) - 500 i 1000 1 1500 2000 i J>50G j 3000 1 3^00 4000 1 ^500 i 5000 1 C^2T1A ! 24 2 000 58 .2^6 1.551 ! .802 I 0f>0 j 1 . ^ r 1.605 1 1.910 2.170 i 2.447 ! 2.751 • C37T2A 1 2? 2 063 62 .207 .77S 1 .007 1 1.165 1 1.375 1.535 1 . 752 1 3 . 96? ! C32T3 1 27 2.063 62 .262 i .iiQO .'.-15 995

!

1.178 1 1.414 | i.646 1.888 \ 2 . 12C [2.367 1 C32T4 I 29 0 750 62 .370 i .708 ! 1.029 1

- : 1.683 1 2.033 ! 2.372 2.743 !

t TM 0 TP? •54 I.201 1 . 2QO . wl .500 s .602 ! - 1 1 -

• "

; 038 6? .06^ I.118 1 ,m ,?26l . ?7« 1 .VMi 1 . 390 .446 ! I -

I M?T7« 2

= ? Qft 6? .281 1.510 I .747 .0?7 1 1..2P7 1 i .A/io 1 1 .67= 1 . 920 | ? . i -?k C32T&A ! 26 2 000 62 .286 1 . 5<4 1 ! .807 1 .O83! 1.321 i 1.575 1.839 . 2.122 I 2.400 I 2 . 700 n3?rc i 26 ', 038 .261 i.«501 1 .993! 1.2V* I ] .462 ! 1 . 700 1 l.c>43 1 2 . 208 ; Me C32T10 ! 3~ 1 688 62 .360 1.711 1 1.042 1 .371! I.600 | 2.023 j 2 . 377 2.729 f

1 C32T11 ! 31 1 ] Q 62 .^00 1 . 070 1 .414| 1.756 i r

.•" t v" 2.437 2.7C3 ! i C32T1? ; 32 0 .250 62 -"•3 ! .204 1 -293 . 385 1 .478 1 ^70 1 - 1 - 1 - 1 C32T13 1 *4 0 62 .109 ; .199 .289 .3?8i .467 ! .554 ! - i ! - C^2Tl4AlJ 35 2 , 58 .281 i .565 1 .841 .103! 1.377 1 1.649 j 1.981 2.226 ) 2.'i90 ! 2.812

•' ~3?ti6/,l 39 2 063 62 .273 1 .511 1 .738 .977

!

1,214 1 1.465 ! 1.716 1.987 i 2 . 241 1 2.519 C32T21L 1 AO 1 ~ 7 5 62 .40.6 ' .765 ! 1.117 1 .464 i 1 . 825 ! 2.165 ! 2 . 575 2.917 i

' - 1 C3.2T23L 36 0 .116 i .22k . -: - .4^0 -W ! .638 ! - ! \ i C32T26L 1 37 0 875 62 .072 1 .134 .258! .322 1 .387 1 .449 .513 1 i _ |

j II

1 1

i illIII! 1 ill fl!i! 1 1

1 1

1

1. 1

1 ill i i

1

1 ! i 1 1

1 i -ii'alues represent mtxlmum deflection at jr.idspan

NIST NCSTAR 1-1 A, WTC Investigation 199
Appendix B

IOO0 2000 3000 4000 5O00 0000 7000 6000 TOTAL LOAD (2P) IN POUNDS

200 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

NOTES

(1) There are three different lengths of trusses tested. These

three lengths are shown below along with the mark numbers

of the trusses which have that particular length.

59'9" 58' 11" 35*8"

C32T1A C32T3 C32T5

C32T2A C^2T4 C32T6

C32T7A C32T9 C32T12

C32T8A C32T10 C32T13

C32T14AL C32T11 C32T23L

C32T16AL C32T21L C32T26L

(2) Refer to this test number to obtain more information about

the truss and the test results.

(3) Refer to S.H.C.R. drawing number 7-AB1-54 dated 2-15-68 and

revised 11-25-68 which gives the camber at mid span for each

type of 32" truss.

(4) Refer to Laclede Contract Y7TC-221.00 (October, 1967) pages

TF1-2. 3 3 ^ £nd 21. Design loads were not given for trusses

C32T14AL, 16AL, 21L, 23L and 2oL. Their design loads v;ere obtained from Gene Chorny of S.H.C.R.

(5) Two equal j concentrated leads were applied to each truss.

Each load was applied at a panel point. The target load

shown in the Table on page one is the magnitude of each

applied concentrated load; the total load on the truss

would be double this value. This target load is not the

actual load at which the deflection listed below it occurs because the load cell reading in pounds does not equal the

load applied to the truss by each hydraulic jack. The

target load is very close to the actual load and is used

for clarity in the table. The corresponding actual load

for each target load is as follows:

Target Load Actual Load

500 499.8

1000 999-6

1500 1499.8

2000 1999.2

2500 2499.O

3000 2998.8

3500 3498.6

4000 3998.4

4500 4498.2

5000 4998.0

For information on' testing procedures, equipment used, and

positioning of loads for each truss, refer to Flexural

Test Sheets Nos. 23 thru 40.

NISTNCSTAR 1-1 A, WTC Investigation 201
Appendix B

CC: R. D. Bay

J. R . Paul

September 7, 1967

A. C. WEBER

WORLD TRADE CENTER

SHEAR KNUCKLE TEST

Enclosed are Sheets 1 and 2 dated September 7, 1967.

Sheet 1 of 2 gives the results of transverse loading of shear

knuckles. Lightweight concrete similar to the type to be used

on the World Trade Center was used in this test. Specimen #2

(compressive strength of 2600 psi at 27 days) failed at 30,100*.

Support brackets were not used on this test and rotation of the

slabs obviously lowered the ultimate capacity. Specimen #1 had

a 6 day compressive strength of 1330$ and a total shear capacity

of 37,070?., The side slabs were restrained from rotation on Specimen #1. The average shear transfer per knuckle for the two tests was 16,800$.

Sheet 2 of 2 gives the results of longitudinal loading of shear

knuckles. Standard concrete (average strength of 3800 psi) was used in this test. Tne average maximum load resisted by five

specimens was 55,230$ or 27 ,615#/shear knuckle.

J. R. Paul

sak

202 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

S£\2owk ^Mxoui* £3/0/ August 10, 1967

Mr. Wayne Brewer

Skilling, Helle, Christiansen

and Robertson

230 Park Avenue

New York, Hew York 10017

Lear Wayne:

Shear Connectors

World Trade Center Floor Trusses

We are sorry that you could not get to St, Louis last Tuesday

to witness some of the testing on the shear members and the

application of the fireproofing to the painted open web trusses.

I presume Jim White has told you about the application of the

Insulating material on the Joists which apparently worked very

well.

In our conversation with the plastering contractor who handled

the test application and the representatives of the Zonolite

Division of the W. R. Grace Company, it seems that the loss

because of the round webs was far less than they anticipated

and total loss of material with the system as they applied it

would be under 15?. This application involves less material

than a solid section of the same dimensions and is no different

from angle or structural section trusses attempted previously.

For your information, on the shear member testing we have

averaged the bearing values for the shear members with 2,650 psi

concrete and find that a 28,810* average value has been obtained

with some running as high as 33,000#. This is well over the

17 kips we discussed and since the bearing of the shear members

is solely a function of the concrete compressive strength, the

3, 000* material you have specified for the World Trade Center

towers should find excellent transference of top chord compression

stresses to the floor slab. Or. one of the tests witnessed by

Jim White of a six-day concrete with a strength of only 1,330 psi

NISTNCSTAR 1-1A, WTC Investigation 203
Appendix B

de Steel Company

Mr. Wayne Brewer

Skilllng, lie lie, Christiansen

and Robertson Page 2 August 10, 1967

the loading across or normal to the shear members developed a 18,500* average value for shear connector bearing.

One of these specimens is being retained to 28 day strength

although we are not too sure that the very lightweight mix will

be developing much more than 1,800# to 2,000# in the concrete.

Dr. Galambos at Washington University who has been performing

the Steel Joist Institute composite Joist and truss tests, has

told us, and I believe confirmed this to Jim White, that

approximately the same shear value for the Laclede extended web

connectors could be expected in all directions when the shear

connector is attached in a normal concrete top slab. This means

with the 3»000# concrete we could expect a 28 kips transference

value across, as well as in line with the extended web panel

point shear member.

As an aside, I believe Dr. Galainbos told Jim White that in his

tests he has had no measurable stress in the steel top chords

of Laclede joists and trusses indicating that the shear members

have been sufficiently good to take all the compression in the

concrete top slab of the composite design.

We hope to be hearing from you shortly regarding sizing of

members and the design of transverse trusses in the tower corners

where it seems likely that shear members may be limited as you

had planned it, to the primary floor trusses with transverse

trusses furnished without extended web panel points.

Y ours very truly,

t.c : ,r . Jifii tthlie

Skliilng, isell«, Christiansen ar.u Lci>eri*»ut. wr. Lester Feld

Port of l»ew York Authority

204 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

SK1LLING - HELLE-CHRISTIANSEN - ROBERTSON

Consulting Structural and Civil Engineers 230 Park Avenue, Sew York, N. Y. 10017 • \1u.9-S873

John B. Shilling • Helge ]. liclle • John. V. Christiansen « Leslie E. Rohcrtsoit

Consultants April 19, 1968 Harold L. Wotlhingtan

joseph Jackson

Mr. R. M. Monti

Port of New York Authority

Office of the Construction

Manager - Room 1119

30 Church Street New York, New York 10007

Reference: The World Trade Center Contract WTC-221.00, Laclede

Load Tests

Dear Ray:

Attached are load test sketches 1BV and 1BH dated 4/16/68, prepared by

Laclede Steel Company.

The test pieces and procedures indicated on these sketches are acceptable

for use in tests to establish the strength of the 24T to C32T truss

connections, subject to the following additional requirements:

Sketch 1BV

1. C32T top chords 7"i apart.

2. Tests be conducted with weld X of 1/A"x3", 5/16"x3" and 3/8"x3".

3. Two sets of tests to be conducted -

a. with "knuckle" restrained as shown on 1BV. (SHCR feels that

a load cell can be substituted for the restraint shown, if practical.

)

b. without "knuckle" restrained. This will allow evaluation of the joint strength for the construction loading conditions.

WAVNC A. BfifWfB

P . R, A . fOITIR

rRANK HOCLTCHHOrr

MOBCftT E. ICVICH

V. A. ftft t S A C > K V Kl Ml ft. ftOCK»«

CHAftlCS BANOU«KV WILLIAM 0. W Aft D

. J. VHITt. J ft . LOatHIt L. WIOIMC

II ATTb | OF'ICtt i » . C WASMIttCTOM ftUtLOINC, ||*TTil | WAftWlHGIO* ftftlOl WTC1-87-1

NISTNCSTAR 1-1 A, WTC Investigation 205
Appendix B

S K I LLI N 6 - HELLE-CHRISTIANSEN - ROBE RTS O N

Mr. R, M, Monti April 19, 1968

Sketch 1BH

1. Tests to be conducted with weld X of l/4"x3", 5/16"x3" and 3/8"x3".

2. Load to be applied 1/2" from top of angle (center of gravity).

3. Support of C32T web members close to top chord, as shown on 1BH,

will require test results to be adjusted for the flexibility of

these web members. We understand that this support location is limited by the test machine size. This location of the support

will, however, allow an evaluation of the lateral bending of the vertical leg of C32T top chord angle, and is therefore acceptable.

Except for weld X sizes to be tested, these additional requirements were

discussed with Carl Weber by telephone on A/18/68. Information in boxes

on 1BV and 1BH was added by SHCR.

Very truly yours,

SKILL1NG, HELLE, CHRISTIANSEN, ROBERTSON

Wayne A. Brewer

WABrs

cc: Messrs. A. C. Weber, B. Bay, Laclede

Mr. L. S. Feld, PNYA

Mr. A. J. Guttentag, TRCC

Enclosure

206 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

CC: T, M. Chura

D. 3. Neptune

File Copy

March 18. , 1969

R. D. BAY

RE: TESTS FOR BEARING CAPACITY

OF WORLD TRADE CENTER TRUSSES

The attached sheets summarize the tests conducted Friday, March 7

at the Madison plant. These tests are broken down into two groups.

Group No. 1 consists of seven (7) tests cn various bearing ends of

scrapped trusses to determine the bearing capacity of our World

Trade Center trusses. The results of these tests are on page one while a general sketch of how the bearing end was tested is shown

on page three (Figure 1) . The following is a summary of the test

results

:

1. Only one test resulted in a broken weld and this was at a load 18K greater than the load which caused

the initial bending of the angles.

2. Using a 2" plate instead of a h" plate for the

bearing surface results in a more critical loading

condition and an earlier angle deformation.

3. The core end withstands a greater load before

failure than the column end. This can probably be

attributed to a smaller L/P. ratio and a raore compact

section.

k. Arc welding the bottom of the vertical VI strut

decreases the possibility of a weld failure. The

failure which occurs is then a failure of the bearing

angle which begins to deform noticeably at arroroximately 30K.

Group No. 2 consists of four (4) tests on bearing ends having only

arc welding joining the web and angles together; i.e., no resistance

welding was used. The purpose of these tests was to determine the

strength of repaired bearing ends that v/ould be welded onto our

trusses at the jobsite. Two types of tests were performed. The

first type of test shown in Figure 2-A, page 4 tested the capacity

of the end as a unit. The second type of test shown in Figure 2-B,

page 4 tested the strength of each joint in the bearing end. The

results of these tests seem to indicate that those bearing ends arc welded to the trusses at the joosite will be strong enough to support the required load if the welding is performed by a qualified

welder under good supervision.

David B. Neptune

ds

NIST NCSTAR 1-1 A, WTC Investigation 207
Appendix B

SHILLING. HELLE. CHRISTIANSEN, ROBERTSON

Conaukiuii Structural and Civil Engineers 250 Park Avenue, New York. N. Y. 100/7 • Mu. 9-HS74

John B. Stilling Hclge J. I Idle • John V. Christiansen • Leslie E. Roberkon

November 3, 1969 w

File: WTC-235C CenoUmt,

ttaiota" L. XVotthington

Iw.eph y. jockson Mr. Lester S. Fcld

Port of New York Authority

World Trade Center Planning

111 Eighth Avenue

New York, New York 10011

Reference: The World Trade Center Contract WTC-235.00, Bethlehem Fabricators

Stud Shear Connector Capacity with Rollform Type "B" Steel Deck

Dear Lester:

At your request, we are forwarding to your attention the following information

regarding a test program to establish the capacity of 3/4 inch diameter by

inch long stud shear connectors when welded through the valleys of Rollform

Type "B" steel deck.

Two 15 foot long test beams conforming to Attachment §1 are required. During

the testing operation s the load-deflection and load-slip behavior for each

beam should be determined using three <3) 0.001 dial gages and eight (8) SR-4 type A-l strain gages in accord with Attachment S3.

Load should be applied in 6 kip increments and readings at all gages should be

recorded before the next increment of load is applied.

Six A'-3" long pushout specimens are required in accord with Attachment #2,

four (4) with steel deck and two (2) with solid slabs. The load-slip behavior

of each specimen should be determined by using two (2) 0.001 inch dial gages, one for each pushout slab. Dial gages should be mounted as shown in Attachment

*2, and readings should be recorded for each A kip increment of loading.

Lightweight concrete required for the test specimens and test cylinders will

amount to approximately 85 cubic feet. We recommend use of Nytralite lightweight

aggregate, Master Builders Pozzolith 100R and MBVR, and Type III (high-early)

cement of the brand on hand at the local ready mix concrete source chosen to supply

the 110 pound (air dry weight)f'c 3000 psi concrete for the test specimen*.

a o • « ft t c. t.l MONK HO«*..»t

ft C « ft . ft © i *-«»ftt«» A MtlOVt'

E 41 M C f W . LIU

J O W T « I ft ft € ft

ll.f Til ©

i

208 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

SKI LLING - HELLE-C HRISTiANSEN - ROBERTSON

Port of New Vork Authority

Attention: Mr, Lester Fold -2- Kovember 3, 1969

The recommended concrete mix is as follows:

Cement (Type III) 540 ti Sand* 1275 $

Lightweight Aggregate** 900 0 (3/4 M to #4)

Admixture Pozzolith 100R 24 oz. MBVR 3 to 5 oz. Water 36 gallons

Air Content 6 per cent

* Natural sand, fineness modulus 2.40 to 2.70, specific gravity of 2.65 assumed.

** Nytralite aggregate, specific gravity of 1.45 assumed.

Based on the above, a minimum of 3000 pounds of Nytralite aggregate will be required.

Barring unforeseen events, Nytralite could provide aggregate at the test location

upon three (3) days notice. Pozzolith 100E and MBVR are available upon a notice of

one or two days.

Regarding concrete test cylinders, the following number of cylinders should be

provided for each batch of concrete used to fabricate pushout and beam test specimens

:

4 - 6 x 12 cylinders - test at three (3) days

4 - 6 x 12 cylinders - test at seven (7) days

4 - 6 x 12 cylinders - test on day of pushout tests

4 - 6 x 12 cylinders - tensile splitting tests per ASTM-A496

2 - 6 x 12 cylinders-air dry weight -cure seven (7) days moist, then dry

21 days at 73.4±2 degrees fahrenheit, 50 ± 2 percent humidity.

Regarding mechanical properties of the 12WF 27 test beam members, two tensile

coupons should be taken from the bottom flange of each test beam centered from

the web and centered on the quarter span point. Two tensile coupons should be

taken from the web of each test beam at mid-height of the web, with one coupon

centered on the quarter point of each beam. The test coupons should conform to ASTM A307, Figure 4, and should be longitudinal specimens.

Mechanical properties of four (4) 3/4 inch diameter by 4 1/2 inch long stud shear

connectors 6hould be determined in accord with AWS Dl.O-69, Section 430.

The remaining specifics regarding fabrication and testing of materials and stud

shear connector test specimens can be finalized at meetings with the Bethlehem

Fabricators and the personnel at the testing facility.

Very truly yours, ySKILLING, HELLE, CHRISTIANSEN, ROBERTSON —Janes White JW:ans

NISTNCSTAR 1-1A, WTC Investigation 209
Appendix B

Wtulil Trade Department

titty I 1<v /<>•". )>•"< !.•!.!•<»•<><• iitii Wli 111?)

CONFORMED COPY January 6, 1970

Fritz Engineering Laboratory

Lehigh University

Bethlehem, Pennsylvania 18015

Attention: Professor Roger G. Slutter

Chairman, Operations Division

Re: THE WORLD TRADE CENTER - Contract WTC-721.00

Laboratory Services - Stud Shear Connector

Capacity with Roll Form Type "B" Steel Deck

Gentlemen:

1. The undersigned, The Port of New York Authority (hereinafter called the "Authority") hereby offers to retain the Fritz

Engineering Laboratory (hereinafter called the "Laboratory") to perform

stud shear connector capacity tests using Roll Form Type "B" steel deck

for The World Trade Center being constructed by the Authority in New

York City including:

A. All tests as outlined in the attached letter

of November 3, 1969 from Mr. James White of

Skilling, Helle, Christiansen, Robertson to our Mr. L«ster S. Feld.

B. Supervision of installation of deck and studs on steel specimens.

C. Furnishing of concrete forms, reinforcing steel,

Type 111 Cement, sand and water for all concrete

slabs and specimens.

D. Casting and curing of concrete slabs and specimens.

E. Submittal of six (6) copies of the Test Report to

the Authority to the attention of Mr. Malcolm P. Levy,

Chief of Planning and Construction Division, The

World Trade Center, Room 300, 111 Eighth Avenue, New York, New York 10011.

210 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

I III 1*1 IK I I II Nl VV M IK K At 'Mil *KI tA

Fritz Engineering Laboratory - 2

- January 6, 1970

II. The Authority has arranged lor the following items to be furnished by others and delivered to the Laboratory by November 19,

A. Two (2) 15 foot long test beams with steel deck and studs installed by others prior to delivery.

B. Four (4) 4'-3" long pushout specimens with

steel deck and studs installed on both flanges

by others prior to delivery.

C. Two (2) 4'-3" long pushout specimens with

studs installed on both flanges by others

prior to delivery.

D. Approximately 3000 pounds of Nytrallte Lightweight Aggregate.

E. Approximately two gallons of Master Builders

Pozzolith 100R and MBVR for use as admixture.

III. As full compensation for the performance of all your

obligations herein, the Authority agrees to pay the Laboratory the sum

of the following amounts:

The Laboratory shall not perform any services beyond the point at which the total payments to be made hereunder exceeds $6400.00,

unless expressly authorized by the Director to perform such services in

a writing which expressly recognizes that said amount of $6400.00 will

be exceeded. In the event said writing specifies a maximum total amount

for services hereunder, this Agreement shall be deemed amended to substitute said amount for the aforesaid amount of $6400.00.

IV. Within 15 days after the receipt from the Laboratory of

the Test Report, the Director will estimate and certify to the Authority

the amount of compensation due to the Laboratory. The Authority will

within fifteen (15) days after the date of such certification of the Director advance to the Laboratory, by check, the sum certified.

V. No certificate or payment shall at any time preclude the Port Authority from showing that such certificate or payment was incorrect or from recovering any money paid in excess of that lawfully due.

VI. The Laboratory shall riot Issue or permit to be issued

any releases, advertisements, or literature of any kind which refer to

1969:

(a) A unit price of $2000.00 per 15 foot beam

test for each of the two beam tests required.

(b) A unit price of $400 per pushout tests for each of the six required pushout tests.

NISTNCSTAR 1-1 A, WTC Investigation 211
Appendix B

llf! PIIKlitP Nl W YORK AIM MOts J IV

Fritz Engineering Laboratory - 3 - January 6, 1970

the services performed hereunder, unless you first obtain the written

approval of the Authority, Such approval may be withheld if for any

reason the Director, in his sole discretion, believes that the publication of such information may be harmful to the public interest

or in any way whatsoever undesirable.

VII. The Laboratory shall promptly and fully inform the Director of any patents or disputes, whether existing or potential,

of which you hove knowledge, relating to any idea, design, method,

materials, equipment, or other matter involved in the services hereunder.

VIII. All drawings, specifications, reports, computations,

records, data, charts, documents or other papers, or any type whatsoever, whether in form of writing, figures or delineations, which are prepared by the Laboratory at any time, either prior or subsequent to signature of this Agreement, by the Authority, its Cotnmiss loners

,

officers, agents or employees, is not given in confidence and may be

used or disclosed by or on behalf of the Authority without liability

of any kind.

DC. All information of any nature whatsoever which is in any way connected with the services performed in connection with this

Agreement, regardless of the form of communication which has been or may be received from the Laboratory at any time, either prior or subsequent to signature of this Agreement, by the Authority, ita Comm is e i oners , officers, agents or employees, is not given In confidence

and may be used or disclosed by or on behalf of the Authority without

liability of any kind.

X. Under no circumstances shall the Laboratory communicate

in any way with any department, board, agency, commission, or other

organization whether governmental or private in connection with the

services to be performed hereunder except upon prior written approval

and instructions of the Director provided, however, that data from man- ufacturers and suppliers of materials shall be obtained by you when and

as you find such data necessary, unless otherwise instructed by the Director.

XI. This Agreement being based upon your special qualifications for the services herein contemplated, any assignment or other

transfer of this Agreement or of any part hereof or of any monies due

or to become due hereunder without the express consent in writing of the Director shall be void and of no effect as to the Authority.

XII. The Director, at his option, may, at any time, and with

or without cause, terminate this Agreement as to any services not yet

rendered. The Laboratory shall have no right of termination as to services under this Agreement without just cause. Termination by either

party shall be by registered letter addressed to the other at its address hereinbefore set forth. Should this Agreement be so terminated,

212 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 3

Fritz Engineering Laboratory - 4 - January 6, 1970

the Laboratory shall receive no compensation for any services not performed, and the Laboratory shall be paid as full compensation for services performed an amount computed as above set forth.

XIII. This Agreement shall he effective as of November 14, 1969. All of the services hereunder shall be performed as expeditiously

as possible. The services shall in any case be completed on or about

February 1, 1970. Time is of the essence of performance of all your

services under this Agreement.

Any services performed for the benefit of the Authority

by the Laboratory at any time, if expressly and duly authorized by the

Director, shall be deemed to be rendered under and subject to this

Agreement (unless referrable to another express, written, duly executed

agreement) , and no rights or obligations shall arise out of such services

except as may be provided for under this Agreement.

XIV. The entire Agreement between us is contained herein and no change in or modification, termination or discharge of this Agree- ment in any form whatsoever shall be valid or enforceable unless it is

in writing and signed by the party to be charged therewith in the manner

hereinbefore expressly provided shall be effective as so provided.

If the foregoing meets with your approval, please indicate your acceptance by signing the enclosed copy of this letter in the lower left-hand corner and returning it to the attention of

Mr. Malcolm P. Levy, Chief, Planning and Construction Division, The

World Trade Center, Room 300, 111 Eighth Avenue, New York, New York 10011.

Very truly yours,

THE PORT OF NEW YORK AUTHORITY

Guy F. Tozzoli, Director

World Trade Department

FRITZ ENGINEERING LABORATORY

LEHIGH UNIVERSITY

Titi e J>/toca/t . £pew7?OA/<

Dat e ^ASUsy j£ /ftO

NISTNCSTAR 1-1A, WTC Investigation 213
Appendix B

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214 NISTNCSTAR 1-1A, WTC Investigation
Appendix C

Supporting Documents for Chapter 4

This appendix contains the supporting documents that are referenced in Chapter 4 of this report. All of

the documents contained in this appendix are reproduced with permission of The Port Authority of

New York and New Jersey. Table C-l contains a summary of supporting documents and their location

within this appendix. The footnote numbers given in the table correspond to those in Chapter 4.

Table C-1. Supporting documents for Chapter 4. Footnote Number Document Title Page(s)

1 Memorandum of Understanding Between the New York City

Department of Buildings and the PANYNJ, 1993

216

2 Supplement to Memorandum of Understanding Between the New

York City Department of Buildings and the PANYNJ. 1995

221

NISTNCSTAR 1-1A, WTC Investigation 215
Appendix C

THE S^mTAUTM0RITY(M?R!K7©M

November 5, 1993

One Wcwid l<ade Cemef New York New Yok 100<C

Law Oopanmcnt

Je!I<eyS G'eeo

Gcnetat Counsel

Lawrence S Hotnotc. Oici

Finance Division

(20 1) 061-6600 x6220

Charles G. Sfurcken, Deputy General Counsel

The New York City

Department of Buildings - Executive Offices

60 Hudson Street

14th Floor

New York, New York

Dear Mr. Sturcken:

THE POET AUTHORITY OF N Y AN J TENANT CONSTRUCTION REVIEW UNIT RECEIVED

NOV 0 9 1993

NOTED..

REfERRED TO

Enclosed please find a fully executed original of the Memorandum

of Understanding between the Port Authority and the New York City

Department of Buildings.

For your information, the gubernatorial review period for the

enclosed agreement will end at- midnight Wednesday. November 17, 1993. It has been a pleasure working with you on this matter.

Very truly yours.

A

Walter M. Frank

Deputy Chief, Finance Division

Law Department

Enclosures

cc: William H. Goldstein, Deputy Executive Director. Capital Proarams

bcc: J.S. Green. P.S. Cooper (51 N) . A.A. DiNome (68S), E.J. Fasulio (72S),

L.S. Hofrichter. F.J. Lombardi (72S), C.J. Maikish (35E), A.J. Raiola,

S.T. Van de Walle

216 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 4

MEMORANDUM OF UNDERSTANDING BETWEEN THE NEW YORK OITY DEPARTMENT

OF BUILDINGS AND THE PORT AUTHORITY OF NEW YORK AND NEW JERSEY

This Memorandum shall govern the relationship between the New

York City Department of Buildings (the 'Department*) and the Port Authority of

New York and New Jersey (the 'Port Authority*), both parties entering iato this agreement with the intention to establish procedures to be followed by the

Port Authority for any building construction project ('Project'), to be undertaken

by the Port Authority or any of its tenants at buildings owned or operated by

the Port Authority and located in the City of New York (the 'City), to assure conformance of Projects at such buildings with the standards set forth in the

New York City Building Code (the 'Code').

While the facilities of the Port Authority, an agency of the States

of New York and New Jersey, are not technically subject to the requirements

of local building codes, the long-standing policy of the Port Authority has -been

to assure that its facilities meet and, where appropriate, exceed Code

requirements.

The purpose of this Memorandum is not only to restate that longstanding policy as part of an understanding with the City but . to provide

specific commitments to the Department, as the agency of the City responsible

for assuring compliance with the Code, regarding procedures to be undertaken

by the Port Authority for any Project at its facilities in the City to assure that the

buildings owned or operated by the Port Authority within the City are in conformance with the Building Standards contained in the Code.

Accordingly, the Department and the Port Authority hereby agree

as follows:

1 . Port Authority Review. To assure conformance with the building

standards set forth in the Code at the time of the design and construction of

any Project, the Port Authority shall, in the case of each Project, thoroughly

review and examine all plans in connection with such Project for conformance

with the building standards set forth in the Code. Plans prepared for Projects

to be undertaken by Port Authority tenants shall be prepared and sealed by

a New York State licensed professional engineer or architect retained or employed by tenant; plans prepared for Projects to be undertaken by the

Port Authority shall be prepared by a New York State licensed professional

engineer or architect employed or retained by the Port Authority. The Port

Authority's examination of plans shall be conducted by New York State

licensed architects and engineers retained or employed by the Port Authority.

The Port Authority engineer or architect approving the plans for any Project

from the standpoint of Code conformance shall be a New York State licensed

architect or engineer who shall not have assisted in the actual preparation of

such plans.

2- Project File . The Port Authority shall maintain a file (the "Project

File") for each Project which file shall at all times contain the most recently

1

NIST NCSTAR 1-1A, WTC Investigation 217
Appendix C

prepared drawings, pians and any other documents required in connection

with the review of the Project from the standpoint of Code conformance. In the case of any Project being effectuated by a tenant of the Port Authority

(a 'Tenant Project") such file shai! also include the Tenant Alteration Application

prepared by the Tenant. In the case of any project administered by a line department of the Port Authority, such file shall include any construction

application prepared in connection with such Project. The Line Departments

of the Port Authority are currently its World Trade, Aviation. Interstate Transportation, Port, and Regional Development Departments.

3. Project Certification . For each Tenant Project, the Port Authority

shall require the Tenant to obtain the certification of a New York State licensed

architect or engineer that such Project was constructed in accordance with

the approved plans and specifications for such Project. For any Project

effectuated by the Port Authority, the Chief Engineer or his successor in duties

shall certify that the Project was constructed in accordance with the approved

plans and specifications for the Project. Certifications for each Project shall be

maintained in the Project File.

4. Copies of Project File . The Department • may at any time

request the Port Authority to provide it with a copy of any Project File and the

Port Authority shall" promptly provide a copy of the Project File to it.

5. Variances. The Port Authority shall promptly advise the

Department of any Project approved by the Chief Engineer of the Port Authority which involves, in the judgment of the Chief Engineer of the Port Authority or his successor in duties, a variance from the clear requirements of

the Code, in the event that the Department disagrees with the manner in which questions of Code conformance have been or are proposed to be

dealt with in connection with such Project, if may so advise the Authority. The

Port Authority shall seek expeditiously to resolve the matter. Any matter of

Code conformance in connection with such Project which the Department

believes involves an unacceptable variance from the requirements of the

Code shall be subject to the further review of the Port Authority Board of

Commissioners. The Commissioners shall be advised of the Department's views on the matter.

6. Inspections and Surveys. The Port Authority shall continue to

conduct or cause to be conducted all building inspections, during both

construction and post-construction periods, required under the Code. In addition, the Port Authority will continue to perform structural integrity

inspections on a cyclical basis for all of its structures located in the City.

7. Port Authority Responsibility. As indicated above, the purpose

of this Agreement is to set forth certain basic understandings between the

Department and the Port Authority. It is understood, however, that the Port Authority with its tenants shall continue to bear the responsibility for life safety

in buildings at its facilities and nothing in this Agreement is intended to impose

any obligations of inspection or review on the Department. The Department

shall refer back to the Chief Engineer .of the Port Authority any requests for

2

218 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 4

information or interpretation which it may receive from tenants of the Port Authority with respect to any Project.

8. No Personal Liability . No Commissioner, officer, agent or employee of the Port Authority or the Department shall be held personally

liable under any provision of this Agreement or because of its execution or attempted execution or because of any breach or alleged breach thereof.

IN WITNESS WHEREOF, the parties hereto have caused this instrument to be signed, sealed and attested.

THE PORT AUTHORITY OF NEW YORK

AND NEW JERSEY

By:

"^^-^

Stanley Brezenoff

Executive Director

ATTEST:

Secretary

DATE:

3

NISTNCSTAR 1-1A, WTC Investigation 219
Appendix C

XHESPORT AUTHORITY OF NEW YORK AND NEW JERSEY _Memoraadu

Commercial Litigation Division (6SE)

18 All : 02

TO: Lysa Meduri, Acting Secretary

FROM: Walter M. Frank

DATE: October 16, 1995

SUBJECT: Transmittal of Letter Agreement - NYC Department o^Qildings

Chief m

Office

AtV.l O PIS*K •' D tap* -«<?•" O txtjft »!>! .'

ftcceh?J: U.-.t C 4:

Copy to: J. Green, N. Chanfrau, P. Cooper, W. Goldstein, H. Henschel, F. Lombardi

Transmitted for the official records of the Port Authority is a Letter Agreement

between the Port Authority and the New York City Department of Buildings providing for a change to the recent Supplement to the Basic Memorandum of Understanding between the Department and the Port Authority in connection with the Port Authority's Tenant Self- Certification Program at the World Trade Center.

Walter M. Frank

Deputy Chief

Commercial Litigation Division

WMF:gk

Encl.

220 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 4

THE PORT AUTOORm©C?(^©KkD One Worso Trace Ceme? Ne* York N Y 10046

September 15. 1995

William H Goidsicn Deputy Executive Director

Capital Programs

(212)<35-8<15

;20l) 961-6000 x6<:)5 Honorable Joel A. Mlele, Sr., Commissioner

Department of Buildings

City of New York

60 Hudson Street New York. New York 10013

Dear Commissioner Mlele:

As you know, the Port Authority of New York and New Jersey (the 'Port Authority*) and the New York City Department of Buildings (the 'Departmenf) recently

executed a supplement (the "Supplement*) to the Memorandum of Understanding

between the Department and the Port Authority to provide that the Port Authority's

tenant at the World Trade Center couid. In lieu of any review by the Port Authority, use New York State licensed architects or engineers meeting qualifications to be

established by the Port Authority to: (A) prepare and review such tenant's plans for the construction of any project and certify that such plans conform with the budding

standards set forth In the New York Ctty Building Code and (B) certify that such project

has been constructed In accordance wtth the approved plans and specifications for such project.

As you also know, the Supplement provides that the person or firm performing the review and certification described In (A) above shall not be the same

person or firm providing the certification described In (B) above. A copy of the

Supplement b attached.

This letter wiii-confirm the agreement of the Port Authority and the

Department that, notwithstanding the last sentence of paragraph 1 of the Supplement, a single licensed consultant may make both certtfkxrtlons described In (A) and (B) of

such paragraph, except where the alteration would change the character of the

occupancy group under paragraph 27-237 of the New York City Building Code which

would have been applicable to such space had such space been located In a

privately owned bulking.

If the foregoing meets wtth your approval, please be good enough to

sign this letter on behatf of the Department where Indicated below and return one of

the originals to me. h tight of the fact that three originals of the Supplement were

furnished to the Department, we have, for your record purposes, executed In total four

originals of this letter.

Very truty_ yours.

WUttam H. Goldstein

Deputy Executive Director

Capital Programs

OF BUILDINGS

NISTNCSTAR 1-1A, WTC Investigation 221
Appendix C

SUPPLEMENT TO MEMORANDUM OF UNDERSTANDING

BETWEEN THE NEW YORK CiTY DEPARTMENT OF

BUILDINGS AND THE PORT AUTHORITY OF NEW

YORK AND NEW JERSEY

in November, 1993 the New York City Department of Buildings (the

'Department") and the Port Authority of New York and New Jersey (the 'Port Authority') entered into the attached Memorandum of Understanding (the

"Memorandum*) establishing certain procedures for the purpose of helping to

assure conformance of construction projects to be undertaken at buildings

owned or operated by the Port Authority in New York City with the standards

set forth In the New York City Building Code,

Recently, the Department Implemented Its own optional plan

.

review system providing for professional certifications of applications and plans

and subsequent construction work falling under its jurisdiction.

The purpose of this Supplement to the Memorandum Is fo provide

under the Memorandum for the adoption by the Port Authority of a procedure*

under which any Port Authority tenants at the World Trade Center may utilize New York State licensed architects or engineers to certify. In lieu of any review

by the Port Authority, that (i) the tenant's construction plans are in conformance with the standards set forth in the New York City Building Code,

and CD construction has been performed in accordance with such plans, ft being understood that the persons making the certifications described in (i) and (ID shall not be the same.

Accordingfy, the Department and the Port Authority hereby agree

that the Memorandum Is amended as follows:

1. Professional Certification. Nofw^hstaoding anything to the

contrary in the Memorandum, the Port Authority may, in Eeu of any reviews or

certifications by the Port Authority provided for In the Memorandum, provide

procedures pursuant to which Its tenants at the World Trade Center may utilize New York State licensed architects or engineers meeting qualifications to be

established by the Port Authority to (A) prepare and review such tenant's plans

for the construction of any project and certify that such plans conform with the

building standards set forth in the New York City Building Code and (B) certify

that such project has been constructed in accordance with the approved

plans and specifications for such project. The person or firm performing the

review and certification described in (A) above shall not be the same person

or firm providing the certification described in (B) above.

2. Other Provisions. Except as provided herein, all the terms and

conditions of the Memorandum shall remain in full force and effect.

3. No Persona! Uability, No Commissioner, officer, agent or employee of the Port Authority or the Department shall be held personalty

222 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 4

Robte under any provision of this Supptement or because oi its execution or attempted execution or because of any breach or alleged breach thereof.

IN WITNESS WHEREOF, the parttes hereto have caused this Instrument to be signed, sealed and attested.

ATTEST: THE PORT AUTHORITY OF NEW YORK AND

NISTNCSTAR 1-1A, WTC Investigation 223
Appendix C

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224 NISTNCSTAR 1-1A, WTC Investigation
Appendix D

Supporting Documents for Chapter 5

This appendix contains the supporting documents that are referenced in Chapter 5 of this report. All of

the documents contained in this appendix are reproduced with permission of the The Port Authority of

New York and New Jersey. Table D-l contains a summary of supporting documents and their location

within this appendix. The footnote numbers given in the table correspond to those in Chapter 5.

Table D-1. Supporting documents for Chapter 5. Footnote Number Document Title Page(s)

Section 5.3 - Damping Units

Letter dated July 16, 1964 from Alan G. Davenport of WSHJ to Carl A.

Dahlquist of 3M (WTCI-450-L)

226

3 Letter dated November 23, 1964 from Richard D. Steyert of WSHJ to Carl A. Dahlquist of 3M (WTCI-450-L)227

5 Internal correspondence dated February 1966 by Richard D. Steyert of

WSHJ (WTCI-450-L)

231

7 Letter dated October 31,1 966 from Don Caldwell of 3M to James White of

WSHJ (WTCI-501-L)

232

8 Letter dated October 30, 1967 and enclosure from Leslie E. Robertson of

SHCR to John H. Kyle (Chief Engineer). PONYA (WTCI-501-L)

240

10 Letter dated April 4, 1969 from Leslie E. Robertson of SHCR to Malcolm

P. Levy of PONYA (WTCI-501-L)

248

l l "'Specification for Viscoelastic Damping Units" dated October 6, 1969

(PONYA 1969) (WTCI-501-L)

252

NISTNCSTAR 1-1A, WTC Investigation 225
Appendix D

WORTHINQTON, SHILLING, HELLE & JACKSON

•Connthhig Ch'il «««{ Sfrnetwul Un^iureu * tH4f} UWungion Bid*,, firtmtc, Wafh* 9SI01 * AIu. 3-722*

fHaroM L. V1'nnlil'M|{lO« * fahii ft, • IWi[r / llrllc • }tmj>h I )nck%t>n ' )o)nt V. C'msrionjfii

-July 16. 1964

Mr. Karl Dika*qu*»t

2-M Comp»ay

Mlnnesote Mining And Manufacturing Company

2501 Hudson Road

ULuasipolls. :*lir=L

Hofsrcnca: Vi»co*l*BUc Damping Material

Dear Mr. Dahlqulat:

We have an important requirement for a vlscoelastlc material suitable for

damping low frequency mechanical vibrations. It ia proposed that this material shall be used in a sandwich between two surfaces and the load will be

applied to the damping material by shear. The frequency of vibration is in

range 0.1 - 1.0 cycles per second. Tbe operational temperature range will

be 0° F - 80° F. It will have a chemical and mechanical stability such that

its action is unimpaired ever the course of many years

.

We would be grateful if you could suggest what range of materials might be

available for such a purpose, their approximate cost and all their portinent

mechanical properties. We have a hunch that an aephaltic or rubber based

material might be suitable.

We require to know the storage and loss moduli (c.f. p. 36-16 of "Shock and

Vibration Handbook" by Harris and Crede, McGraw-Hill, 1959) over the above

operating temperatures and frequencies. (We are looking for a material with

a loss modulus probably of the order of lo* lb/sq. in.) We would also like to know the chemical composition of the material and its melting point.

If the material Is adopted it will be used in considerable quantities. We

would be grateful, therefore, if you would al«o indicate approximately bulk

coats and availability. Your early reply to this inquiry will be appreciated.

Yours very truly,

AIsz G. Pavenport Ph.D.

ACD:ab

C

V. ». ""».». D •* T l»»u« *, mmnrao „

o»»»v»» Umouw*

">••«'• V.. Di.a \

» WUMMtlM oonMWATtON luimmme aw»i««<t.»»a wnvien *"» wmdm w> »u»»»vi»k»» or umihs noriweiui «-<H,

226 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

WORTHIN6TON, SKJLL1N6, MELLE & JACKSON

Consulting Civil and Structural Engineers ' 230 Park Avenue, New Vert, iV. Y. 10017 * Mu. 9-SS74

Harold JL Wonhincion • )A- B. Sk3K»X • Krig* )• Hclle ' )cvrh F. )acku>M John V. Chritthmen ' ljciKt E. Rolcmcm

Hovember 23, 1964

C. A. D«alquist

Minnesota Mining Manufacturing Company

2501 Hudson Road

gSfcSgffstcs; Tiacoaiastic Dmping Material

Dear Mr. Dahlauist:

Thaak yon for tho information which you provided during our phona convtr-

•ation of November 11. We have enclosed a sheet which Hats the types of

viecoelssclc damping aaterials and the properties desired. Ve have alto

ancloaed a sheet which revlewi the properties at Che IA66 Transfer Tape.

Ua would greatly appreciate any i*lto*s»atiort whlah you would be able to provide on other materials nroduced by Vha Minnesota Mining and Manufacturing Company. Such i^ferB'tios vpvld hm appreciated at your earliest

convenience. \ \

Sincerely yourt,

WORTHINCTON, SXILUNG, HELLE & JACKSON

Richard D. Stoyert

cc: Mr. Caldwell

RDS:cd <• • *• »o»'**«

noun K. LKVXM

mat m. «o»i««

CM**!.**

*rt4>vi**> o, *»•»

K. 1. UHlTIi J ».

i m a t o w » • I o »

NIST NCSTAR 1-1A, WTC Investigation 227
Appendix D

WORTHIN6TON, SKILLING, HELIE & JACKSON

Consulting Civil and Structural Engineers * 230 Park /•Uvinu*. New York, N. V. 10017 • All*. 9'8S7«J

Haterl&l: £466 Tranif«r Tape

Pirc^ecars: G ?r«» 200 to 300

from 1.2 co i.a

c - .0015 In.

Coat:

Additional

Properties:

Max 2 20

$1.52 to $2.00/

Bonds to ste or concrete

228 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

V/b RTHINQTON, SKI LLI N HELLE & JACKSON

Consulting Civil end SsmaunJ Engineer, 230 Park Avtnu*, Nrw Yen*, N. Y. J00J7 M*. 9^874

Phvalcal S Mechanical Propertlet Keaulrcd of Viaco-EUitlc yatyrlal

1. Type A. Ease of placement Into void cither by pouring or pumping unaer pressure ana/ or neat ana capable or conning to concrete,

steel or wood.

Type B. Available in eheete.

*. A high degree el durability and stability under normal operating

condition* -for .extended periods. (It la possible that the containing space 'cos be aealeU^hermetically.)

3. Non-combustible.

1. Loss of modulus in shear, C2

loss factor , n - C2/G1

for temperature range 30° - 80° F. vibration frequency .1 - 1.0 cycles/aecono.

2. Stress or strain or fatigue limitations.

3. Cost.

Note; Quantities to be used 1,000 c. f

.

1 plus or minus by a factor of 10.

. O

«o c (S^si

>. - ; 1,2.. I. 5

Via.

•J->

NISTNCSTAR 1-1A, WTC Investigation 229
Appendix D

WOfiTwWCTOM. KILUNC.

MCI.LE ft JACKSON

CUIl ft SHvtl««sl EnglxMn

THE WORLD TRADE CENTER SSK 8^ Shwrt

HINONU »««»l»n » »»»oc. (XIV MOTH • toxt APPROVCO

-.QSDfiSZr £L.XL^Jg.^ZEEy££JZ. Kr=====r=====

iufari: c/o/i*. prior to rfcy.

WoJj ore/er-Sef "ft /mat

No Ac - ftH*e*>jh J dav*. crass c/ec^f»' i^/a >*orK

sts "ffici** //y ^6 /e«/ /7" cooi/S^nf with

2>«i c<treff//y cAe<J<co/ a#at o**,c/*r •food by Je<«eo«e

*rus t0 %

pIp9

fJetos', ' k**e. cfoc^<i<>/ This wor-kj buff AoT txteHSivtly.

Th^rc appears £c <? (/'jcre^c/ic^ ^«;7«/e«?>f

£?/c*; Tiny/or 1* **yjrk haJ fity *#erk t** 7 his <t/-«q. T^fi wark is erf * s/^p/z »a7t/re.

} not mv*fft*)

ce »*i p»lG r,

©* fry5.3

230 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

>6TOX. iKlLUfcC. THE WORLD TRADE CENTER ASSISETM*,,, CATC J*. 66 tia. MIMOftU Kl t MSCC. E*C*V KOTN « SONt

MlbOOO Ityiltll, AtCfclTfccr »irn4*ft iCTH, ««C**|TtCY

Co^Z-ocf- wit-Li -3H- Cen pa ny

tenths. C*>*T«<.r h + i i>e«/i n^/tk C<a /orV 4 i! —

eOfn/ers+Tions. E>jck To>/Ur />«< £<£<i/» j* <*// recent

cor> i/erjaTiw.:, 7"A« j<=/»er«./ *1+ti><, /j 4+J/e»,jaj:

Initial T&s1s to/- r« le^Tse* o T rt:ci)-;i;*;; mm+,inci*i^l

Jn/T>*l cciT ei"7/—

«

tS? » Q vis**/ , /"'Tj^/A,

-fri,3 3 a/a ~,per- VM,r 27?. <*»J <eA,^„ J* *~,/°*>r ^Sf. /9 s

r<Zf, J 9 a/

) Truss dlmi^prr /5 W <.ohmn hamper /5"f,

Tz-stir.y or «*> aar.^Ll€a/ Trirss ata.*nfrij *«,T Aas ^e©*j

A'* sAn,/<S rei/i*^, our

a/* 3>yr> c-f th*. <*V»i/«/- </»tT <9r>e/ "for *j* rV J^'J «/<?s/^yf

5"«/7 /j <*nyice>zJy «MS*itiKf <» jo-a/it-**/ om the. <ze>lv**in ofpmfzi J/3Tt»«. >^7" frese»it~ They e»r« <jp r^e. « /a aI>»*sT 9»r inteffT~tct)i. . They <*Jio arc jv/le aomout To jet svjjest'etS

fro* oil * Tes?/ij projr«»yr for f/<e coJv*~si cj*it> /

z^op/J th)»k « f^a/f otr/- o-f-ftce. &e, ^«//t>/o/

£*ct/lt* t*2. <* ft *.*<-lianj*. a [ -fir/net tio» k, a<J To fain

3-M >» project.

t//> ' r 7"J i?« by <?/» /««/•>/» «?Mc/«r,»f /*b*/-* tvt-y. f~/je Cost

c»st5 s*> v 37 6*. c/nrii'ieJ

NISTNCSTAR 1-1A, WTC Investigation 231
Appendix D

C[NE R Al Off»C£S • 7S0t MUOSON ROAD - ST. PAIR, MINfitSOU SillS . Ill /33-1U0

Industrial T.tpe Division

October 31, 1966

Mr. James White

Worthington, Shilling , Helle & Jackson

230 Park Avenue

New York, New York 1O017

Deer Jiai

The paragraphs below contain our proposal for the qualification

section of the specification, a revised Acceptance Testing and Stapling Plan and a section on the burning and aelting of the visco-eiastie

material. In addition, confirming our telephone conversation of 10/4,

we agre« to loosen the location tolerance of the four corner holes in

the T-Sectiona from t 1/64" to 1 1/32", Our Engineering Department is

producing revised drawings which will be sent to you when coapl«te.

Substitute the following paragraphs for section three entitled

"Qualification of Dampers" that was contained in the rough ftpecir^cation outline given you at the tine of your visit:

"A daaper nay be qualified by presentation of data gathered iron

tests of at least one damping unit. The tests oust be conducted acccrdiris ?« the following procedure *nd meet the requirements listed

in this specification. Report the values iu »«cticns 0, 10, 11 *nd

14

232

H11NNESCTA miNlNS AND irtANUFACTURIrJC C0H1PANY

NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

QUALIFICATION TB511NG PSOCEDUHE

1. Clasp an aaaonblad full seal* dwpar In tha ja*« of tb# 1 natron.

2. bolt tha licroMttr haad to on* of tha T.tactions of tha daapar

walno prrwioualy ax Iliad holaa. Bolt tha ara holdino tha avtansoatattr to tha bar. (Saa attached aketch

}

3. Connect tha output of tha exteneoaetes to tha chart recorder.

4. Record tha diaplaceawnt and force Id ona aida of tha dastper (tha

two a id*a are aaauawd identical) Alternately In compression and

tanaion for ona complete cycle* The 1 nitron la reversed at tha

pre-aelected dlaplscemrat of .020" both in cosprassion and tanaion.

A typical hystareale loop is shorn on tha bottom of this paoa.

L PS./.02O* £X r E N S

I

O n A'BOUNOtO A«EA OF

d i tXTC.Wi.iON, IN. t "THICKNESS VUC0-

EtASTiC MAT-^ IN. d.«A*£A VlSCOEl-ASTic MATL., IN.Z V» VOLUME V«SC0-

EVASTlC LAYERS, IW?

6.' <J/t

r,*=C05S SHF.AH

MODULUS, PS1

<a*a COMPLEX 5HEAR

MODULUS, PS1

N!ST NCSTAR 1-1A, WTC Investigation 233
Appendix D

234 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

5. MtMure the bounded area of the loop. Calculate the strain, <£©

and volume, V, in the vieco-elaetic layers.

6. Calculate G

M froa the equation GH * A ,

7. Calculate G» frca the equation G* £

ad

t 8. Calculate G« from the equation (G') 2 (G*) 2 - (G") 2

9. Calculate loss tangent* tan £ , froa the equation.

tan £ » G"

G»

10. Record the value F taken froa the chart recorder.

11. Run at least 100 successive cycles of the hysteresis loop test at a displacement aaplitude of 0.020". Calculate the loss modulus,

G", as shown above, for the first and the last cycles. Calculate

the percent change of the last cycle froa the first.

12. Place an assembled daaper in the jams of a Baldwin test machine

(of at least 60,000 pounds capacity in tension and/or compression)

with the bar and extending downward.

13. Record the force necessary to cause shear rupture of the viscoelastic bondod area when a compressive load is applied axially

to the ends oJ the daaper unit.

14. Calculate the ultimate abear airmngiu of ths ur.it fcy d*V<dlno the

tAtJii force exerted by the area of the viaco-elastic material."

NISTNCSTAR 1-1 A, WTC Investigation 235
Appendix D

Substitute the following under the section entitled "Acceptance

Testing end Sampling Pies".

ACCEPTANCE TESTING & SAMPLING PLAN: "The plan Assures that dampers having svorsge loss tangent, stiffness*

fatigue resistance end ultiaste sheer strength values less than the

guaranteed ainimuaa will not he accepted aore than 3% of the tine.

Ljvtt A lot shall consist of all dampers made from the sane lot of

visco-elastie material by the saae process and to be submitted for

acceptance testing at one time.

Sampling s Dampers shall be selected at random from each lot at the

rate of one per day for loss factor, stiffness and ultimate shear

strength determinations and at the rate of uoe per lot for fatigue

resistance*

If the quality level of dampers is consistently high, the sampling

rate may be reduced upon presentation of ptoof that such reduced rate

offers at least the saao quality assurance and upon approval of the

engineer.

Acceptance > After the sample dampers have been tested in accordance

with all procedures listed in the Qualification section and have passed

the requirements listed in the Documentation of Performance section of

the specification, the lot is deemed to have been accepted by the contractor.

If the acceptance test data differs from the qualification teat data

because of the relatively small number of tests used for qualification,

the engineer may change the acceptance requirements or grant a waiver

if in his judgment the dampers are still suitable for their Intended

purpose.

In the event a lot is rejected* the following procedure will be followed:

1. Take an additional -ample from the lot coonoaed of dampers chosen

at random at the rate of one from each days production (one per lot

for fatigue resistance).

2. If the cumulative average of the first and second samples are equal

to or below the control limit for the combined sample, take a third

sample from the lot composed of daspers chosen at random at the rate

of one from each days production (one per lot for fatigue resistance).

3. If the cumulative average for samples one, two and three is equal to or below the control limit for the total combined sample, the entire

lot is rejected

We estimate that our production will be 80 dampers per day ox 400 dampers

per normal week, thus, the normal sample size will be five.

We axe subaitting the attached graph and explanatory remarks to illustrate

the Acceptance Testing and Sampling Plan. Obviously a similar graph applies

to stiffness, ultimate shear strength and fatigue resistance. ** w

236 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

OFTHmHG CHARACTERISTIC CURVE

PROBABILITY' Of ACCEPTING TAN 8 = 0.70 (S 0.05

AVERAGE TAN 8 OF LOT INSPECTED

0.3 2jO HO 25.0 SOO 75.0

% BELOW TAM 6-0.7 IN A PRODUCTION LOT

NISTNCSTAR 1-1A, WTC Investigation 231
Appendix D

2,

3,

4,

The curvt gives »v>rtot vtluti of lots that have been eetimated

fxaa samples of five (chosen at mndoa at a rat* of oM per day)

per lot. Vl« are using averaga valuta to daacribe the minimum

quality you can receive in preference to valuaa for a ingle damp-

«ra because*

a. The buildings reapond to the average damping of all daapere

acting in concert.

b. Toe performance requireaenta to inaura no alngle daaper falling below t for example, a loss tangsnt of 0*7 axe ouch great- er. Thia point can easily be saan by rafarring to the abscissa

showing that at an average loss tangsnt of the lot equal to 0.7

50% of that lot will be below .7. It would be necessary to have an average of approximately 1.1 to insure that eaaentially no individual damper a are balow a loaa tangent of 0.7.

It is impossible to conclude anything about the performance of individual dampers from theae curves. This Beans that you aust accept

the chance that some daapers may be released with very low values

,

though the average of the sample will excead the control limit of

0.81 and the probability of accepting a lot average of .7 la only 5%.

Ae an example, assume a lot of dampers whose true average loss tangent

is 0.9. This Beams that 11* produced in that lot would have loss tangent a below 0.7. Thia would be true on All production lots having the same estimated average loss t\agcnt. It further means that approximately 91% of the time theae lots will be accepted. You would receive

•91 x 11% or 10 dempers undur .7 loss tangent.

In a loc, the control limit for the sample of five ia .81 based on laboratory experience to date. Thia can be seen from the 50% probability on the five daaper sample curve occurring at a loss tangent

of .81. A lot having this average control limit would be rejected.

We feel that the abscissa titled "Percent Below Loss Tangent of 0.7

in Production Lot" is a valuable addition to the oraph. It r»u*»t«

uut quality variability (lab experience) to you. You can calculate

variability froa the operating characteristic <?«irve according to the

rollowlng sethodt

a. Note that the "5* point" (the chosen statistical limit } occurs at loss tangent « 0.7.

b. Note that th*> control limit equals .81.

c. Then. .61 - .70 » .11 = 1.645 <rr~

f » For several values of lose tangent calculate lose tangent - .7.

For example, when loss tangent = .8 me get .8 » .7 B .67

.15

g. Then from a table of normal probabilities! the percent below .7 is taken. For the above example , this percentage is 25.

d. From this <r$ .06?

e. » .15

238 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

6. Ths averaoe loss tu>9iut fcS expsriscnt&l rt»»p«r» tested to date is

1.1. It is obvious that wo really h*vt a high confidence of westing

ths at niaua loss tangant of 0.7. Using the five <ia*per sample plan,

the producer* a risk point (95* probability of accepting, 5% chance

of rejecting unknown to 3M) occurs at a loss tas«*«t of .92. Th»

consuatx'i risk point occurs at a loss tangent of 0.7 (5* chance of

accepting a lot whose tru* average is below 0*7).

Add saeticn nine entitled "Burning, Malting and Toxicity" , to the specification: "The beat of combustion of the visco-elastic aaterial shall

not exceed 8500 calories per gram. Coabustion of the vieco-elastic aaterial shall not produce gaseous products worse than those froa typical

vinyl wire insulation. In the event the temperature in a fire is short

of that required for coabustion, the visco-elastic aaterial shall not

aelt and/or drip causing a hazard to fire fighters."

I aa not sura that as gave you ths beat of coabustion figure for Y-9274.

Measured on two saaplss the avsrage was 7,646 calories per graa. While

we expect this to vsry aomewbet froa lot to lot and teat to test, the

variation should be vary saal'i. Tha 850O figure gives plenty of star gin.

The products of coabustion of Y-9274 are siailar to those froa burning

wood. Por exaaple, there is no phosgene as froa coabustion of vinyl

plastic. Tha enclosed piece of typical heavy duty airing coated %ith

vinyl insulation and tba accompanying piece of our visco-elastic aaterial

wrapped around the bars wire gives graphic proof that Y-9274 will not cause

a problem due to Gripping. Both were exposed for fifteen ainutes at 550*P.

You can see that tha vinyl costing dripped seriously whereas the Y-9274

showed not tho slightest sign of dripping. X would expect that it will

burn before it drips.

In discussing aging let us first separate aging into environmental aging

and chemical stability. We are not concerned with environmental aging

because of the absence of difficult factors in the buildings. Our ex- perience with cheaical stability of aateriale in the aaae polyaer family

would indicate an expected daapar life of at least ten years and probably

up to » hout twenty years in the absence of environaental factors. This

includes til components of tha damping unit. I «uwl£ c~cc t *h%* over

this period of ?£met the loss factor and stiffness would remain quite

constant. If there is a change we would expect it to be in the direction of increased stiffness and lowered lose factor but where the product of loss factor and stiffness would increase. Polymers in the Y-9274

family can be compared in aging ability to silicone elastoaers, but are slightly poorer than these rubbers.

1 have decided to make these bald statements without hedging or qualification, but wi rh the firm addition that they in no way constitute a guarantee

and are simply estimates.

Very truly yours,

D. B. CaTdwell

Project Engineer

Acoustic Products

DECidfs

NISTNCSTAR 1-1A, WTC Investigation 239
Appendix D

SKILLIN6 - HELLE-C H RISTIAN SEN - ROBE RTS O N

Consulting Structural and Ci\-il Engineers • 230 Park Avenue, New Yotk, N. Y. J00 17 • Mu. 9-S87-J

]ohn B. Shilling • Uclge J. Hello • John. V, Christiansen • Leslie E. Jlnhcrt^on October 10, C«»uto»*«

Uatald L. \X'or{^in{<o»

hr. John M. Kyle

Chief Engineer

Port of Sev York Authority

World Trade Ccntar Planning

111 Eighth Avenue

Kcv York, how York 10011

Roference: The World Trade Center

Damping Units

Dear Jack:

Enclosed: i« b program outlining a test »;4>rt*.!> tv. hf «. > fcrr tho dnirplng

unit* betveeu floor and column elements of The World Trade Center.

Wo had hoped that a much raore comprehensive program could be developed.

Bovevsr, t«at equipment specifications have proven to be a much higher

hurdle than had been expected because of the difficulty in allowing for

reasonable flexibility in selecting a laboratory and for contracting for

the work. We have, therefore, deleted this facet of the program and have

left tho responsibility f-r outlining teat equlncent renponae and the like

to tho laboratory.

Lcolcir-3 back ov*jr tho history of the development of these damping units,

it is apparent that ShCR should have proposed the test series that you

have requested. We are, then, grateful to you for iinticipating this

requirement ar.J directing our thoughts towari this program.

Very truly yours,

SKlU.lhC-V.ELLE-ClIRlSTlANSLK-P.OnEP.TSOh

Leslie £. Robertson

LER:s

cc: Mr . Maico La P. Levy «»>n *. ******

* . • . *. roitu

pd*m* BGini»HO>r

noatut », t«v**

V. A. »t»19IK1 m «. » o c i « » CMWI.II l»»OV»l

WlillAH D WAUD

t. J. WKITI. J*.

t.O*CNt* l_ WIOIN0

ttttlt.1 OtriCil I « « O WA»MtM«VOM • U I L D I » « . • t » T t l • , » » t H I » I 1 t * » « » © »

240 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

THE WORLD TRADE CENTER

Report No. DU-2

PROTOTYPE TEST PROGRAM

OF

VISCOELASTIC DAMPING UNITS

October 27, 1967

NISTNCSTAR 1-1A, WTC Investigation 241
Appendix D

PROTOTYPE TEST PROGRAM OP

VISCOELASTIC DAMP INC UNITS

I. Introduction

Vlscoelastic damping units have been developed for installation In

the floor system of The World Trade Center towers. The need for and the

theory of the damping units hsve been covered in a previous report,

"Viacoelastic Damping Units" Report No. DU-1 by Skilling~Helle-Christlansen-

. Robertson. Also included in Report No. DU-1 are the results of the prototype

testing conducted by Minnesota Mining and Manufacturing Company. Since this

vlscoelastic damping system ia certainly one of the few applications ever

made, if not the first* in the field of tall buildings, it ia desirable to

have more independent test data on the performance of the damping units.

This report vill cover the requirements of the proposed test program.

II. Damning Units

The damping unit consists of two vlscoelastic slabs, 4" x 10". x 0.05",

bonded alternately among three steel pieces, as shown in Figure X. Steel for

the tees shall conform to the requirements of ASTM A36, and steel for the

center plate shall conform to the requirements of ASTM A36 or AISI C1020

(hot rolled) . The surfaces of the tees to be bonded shall be machined flat

within 0.005 TIR and the thickness of the flange after machining shall be

0.438" minimum. The vlscoelastic alaoa shall be of 3M Brand Vibration

Damping Elastomer 0Y-9274, produced by Minnesota Mining and Manufacturing

Company. Bonding agents between the steel surface and the vlscoelastic

slab shall be selected by Minnesota Mining and Manufacturing Company and

eKILLtNO-HCiLS-CHRIBTIANBCN-ROBERTSON

242 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

shall be identical to the bonding Agents to be used in the final production

of the damping units.

The endB of the structural tees shall be connected to the test jig by

two ASTM A490 bolts, 1" diam. , in double shear; the other end of the unit

shell be connected to the test jig by two ASTM A490 bolts, 3/V diem., in

double shear. Two hardened washers shall be used with each A490 bolt. All

bolts shall be tightened by the tum-of-not method. The structural tees

Bhell have four assembly bolts, 1/4" diao., conforming to the requirements

of ASTM A307.

The damping unit and its fasteners will then be identical to the damping

units to be installed in the buildings, supplied under Contracts VTC-219.00

and VTC-224.00. For the test specimens described herein, the steel pieces

shall be fabricated by a contractor to be selected by the Port of New York

Authority and fabrication of the damping units shall be done by Minnesota

Mining and Manufacturing Company after negotiation carried out for this work.

The testing shall be done by a laboratory selected by SHCR end approved by PNYA.

Forty test specimens of the damping units shall be fabricated. Each

specimen shall be marked with the date of fabrication and with a number from

one to forty assigned according to the order in the sequence of final

assembly of the damping units. Thirty specimens shell be selected at

random and shall be tested in the teat program to be described in this

report. The remaining ten specimens shall be stored by the Port of New York

Authority at relative humidity of AOX 1 10X and at ambient temperatures of

75'F * 3*F. These ten stored units will be used for the evaluation of the

aging effects in a way similar to the guarantee testing of the final production units.

8IMUINa-MELLB-CHRl8TUN8EN-ROBERTBON

NISTNCSTAR 1-1A, WTC Investigation 243
Appendix D

III. Monitoring of Fabrication and Tenting Operation

All work shall be done under the surveillance of the S-H-C-R Resident

Engineer who will be assigned to the production fabrication and field

installation operations and should be witnessed by one or more representatives

of the Port of New York Authority. A representative of Minnesota Mining and

Manrfacturing Company should be invited to witness the tests. The testing

agency shall submit evidence to and receive approval of Skilling-HelleChristiansen-Robertson for the suitability and accuracy of the testing apparatus

to be used in the performance of the tests and shall submit and certify

laboratory data sheets. The S-H-C-R Resident Engineer shall prepare

comprehensive report to describe and evaluate ell phases of the test program

for the Port of New York Authority.

IV. Test Parameters

For the purpose of evaluating the effectiveness of the damping units,

the following parameters shall be measured:

1. Absolute dynamic stiffness of the damping units, defined as the

force amplitude required to cause unit sinusoidal displacement

amplitude of the ends of the damping unit.

2. Lose factor of the damping units, defined as the tangent of the

phase angle by which the relative displacement of the ends of

the damping unit lags behind the applied force in sinusoidal loading.

3. Ambient temperature and- temperature of the viscoelastic slab.

A. Temperature changes in the viscoelastic slab vs. cycles of

oscillation during four hundred cycles at constant amplitudes

of displacement.

6KlUUIN6»HBLkiS*CnNISTiAN8CN-NOBCRT6DN

244 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

5. Maximum displacement and ultimate strength of the damping units

in compression.

V. Tests for Dynamic Stiffness and Loss factor

1. The ambient temperature and the temperature of the viscoelastic

slabs at the beginning of each test shall be 75*F i 3

e F. The

temperature of the viscoelastic material shall be measured by a

thermocouple embedded in an edge of the slab,

2. The ambient relative humidity shall be AOX 531.

3. Each specimen shall be subjected to sinusoidal variation of axial

displacement between the two ends of the damping unit. The

frequency of the sine function shall be 0.100 t 0.005 cycles per

second. There shall be no static force bias on the specimen.

Twenty specimens shall be tested at amplitudes of 0.020 inch and

another ten specimens shall be tested at amplitudes of 0.030 inch.

All specimens shall be tested for one hundred and two cycles of

displacement except two specimens sb specified in Section V.6 below,

A. Force-diBplacement curves of each specimen shall be recorded by an

on-line X-Y plotter for the 1st, 2nd, 10th, 20th, 50th, and the

100th cycles. At the end of the 100th cycle, testing shall be

halted. Testing shall resume when the temperature of the viecoclastic slab returns to its initial temperature plus or minus 0.2°F.

Force-displacement curves of each specimen shall be recorded for the

101st and 102nd cycles. The time elapsed between the 100th and the

10lBt cycles shall also bo recorded.

5. The ambient temperature and the temperature of the viscoelastic slab

BKILUiNO — MEULC — CMRtBTIANBEN-ROBCftTBON

NISTNCSTAR 1-1A, WTC Investigation 245
Appendix D

shall be recorded for the 1st, 10th, 20th, 50th, 100th, and 101st

cycles for each specimen.

6. One speciaen shall be selected fit random from the specimens to be

tested at 0.020" amplitude and another specimen shall be selected at

randoo from the specimens to be tested at 0.030" amplitude for extended

testing as follows: Sinusoidal displacement shall continue to be applied

beyond the lC2nd cycle until the 500th cycle. Force-displacment curves

as veil as the ambient temperature and the temperature of the viscoelastic slab shall be recorded for the 200th, 300th, 500th, and 500th

cycles.

VI. Tests of Maximum Displacement and Ultimate Strength

1. The ambient temperature and the temperature of the viscoelastic slabs

at the beginning of each test of Section VI shall be 75*F t 3*F.

2. After testing in accordance with Section V, each specimen shall be

loaded to failure in axial compression at constant displacement

rate of 0.48 inch per minute. The force-displacement curve shall be

recorded by using an on-line X-Y plotter for each specimen.

3. The mode of failure of each specimen shall be noted, e.g., shear

failure through bonding agent or shear failure of 3/4" diara. bolt.

Where informotive, the failed specimens shall be photographed.

VII. Evaluation of Test Result & Final Report

The prototype damping units shall be considered satisfactory if the

results of the test specimens meet the following requirements

:

1. The mean value of the lose factor of all specimens for the first

cycle shall be at least seven-tenth (0.7).

BKlULINO-MCULe-CtlRISTIANSEN'ROeeRTSON

246 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

2. The mean value of the absolute dynamic stiffness of all specimens

for the first cycle shall be at least 400,000 pounds per inch but

less than 800,000 pounds per inch*

3. The standard deviation of the absolute dynamic stiffness of all

specimens for the first cycle shall not exceed;

(a) j K, - 60,000 pounds per inch

and Cb) 400,000 - y

K

d pounds per inch

vhere is the mean value of absolute dynamic stiffnesB.

4. The limits set forth in CD, (2) and (3). above shall also be

applied to the 101st cycle.

5. Ultimate strength of the damping units as measured in Section VI

shall have a mean value not less than 48,000 pounds and a standard

deviation not greater than { "j P - 12,000 \ pounds, where P is

the mean ultimate strength in pounds.

6. Maximum displacement at ultimate strength as measured in Section VI

shall have a mean value not less than 0.16 inch and a standard

deviation not greater than { ~ D - 0.04 \ inch, where D is the

mean value of the maximum displacement In inch.

NISTNCSTAR 1-1 A, WTC Investigation 247
Appendix D

SKILLING. HELLE, CHRISTIANS EN, ROBERTSON

Consulting Structural anil Civil Engineers • 250 Perk Avenue, New York, hi. V. 101)17 - M». 9-SS7-/

Jo&it B. Shilling * llelge j. Utile • /o/.ii V. Christiansen • Lo/iV K. JloiV»tv.H

Wayne A. Bicivtf

ConiuJffliid Itatnid VC'oJl/mittoti

April 4, 1969

Port of New York Authority

World Trade Center Planning

111 Eighth Avenue

New York, New York 10011

Attention: Mr. M. P. Levy

Reference: The World Trade Center

Contract VTTC-224.00, 3M

Viscoolastic Damping Units

Gentlemen:

Ve have reviewed the draft of Contract VFC~224.00, Viscoelastic Damping Units

for North and South Towers, dated November 1, 1968. Our comments on this

draft contract are the subject of this letter.

1. Draft page 3 COMPENSATION

:

The number of damping units to be installed in North ami South

Towers is 19,423, exclusive of units required for Acceptance

Tests and Guarantee Tests." The Guarantee Tests require

360 units. The number of units required for Acceptance Tests

is variable and it depends on the quality of the submitted lots

and on the number of days of production. Units which arc not

damaged in the Acceptance Tests will be returned to inventory.

However, since it is expected that damping units will be damaged

in the ultimate strength tests, all such specimens should be

discarded.

In order to control the upper limit of the cost of Acceptance

Tests we suggest that the contract include a clause such as, "Vendor shall not be paid the fees for acceptance tests

performed on lots which are rejected as a result of the tests."

MOOIH} %. IKVltN HINT It. HOCf

rtKBLft IANOUIXT

wn.lt A A. D. "AID

LOKfcMIB I. WIDtKG

r . «, a . roittn

Ck N I I T T, LIU

j e> » t % i * mi V. A. PRIIAbtK> mcMAMO e. u»ioa

c. j. wmit, jr. UitiLi erricti i » a t> wasminct»m e u • a. d i h a . • t a t r l c . waahimcion > e i e> i

248 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

SKI LLI N 6 - HELLE — CHRISTIANSEN - ROBE RTS O N

Port of New York Authority - 2 - April 4, 1969

Attention: Mr. M. V, 1-cvy

2. Draft j.age A EXTRA MATERIALS AND DELETED MATERIALS i The unit price schedule in Section B implies that the

total price of 19,999 units is $653,967.30 whereas the

total price of 20,000 units is $622,000.00. A schedule of

unit prices for the deleted units would remedy this situation.

3. Draft pages 9, 10, 11, 12:

The dotes for the delivery of the components and for the

delivery of the damping units must be corrected.

A. Draft page 18 GUARANTEE BY THE VENDOR : The number of units in Section C must be made consistent

with the number given in Draft page 3.

5. Draft page A-5 Items to be Excluded from this Contract : Section 2 should read, "Field bolts in the webs of tecs

and field bolts in the ends of A" x V nominal bars."

6. Draft page A-9, Section 3.1.

A

Change 5 for Shear Stress to lower case c

7. Draft page A-10:

a. Delete the equation for Fatigue Loss in accordance with

the proposed revisions of Section 4.0.

b. Change o for standard deviation to upper case S in order

to nnr*»e with Eq. 1.

8. Draft page A—11:

a. In the first equation for 5, X should he X.

We would like to recommend the following revisions of Section A.0, Requirements

and Section 5.0, Quality Assurance. The aims of these provisions are: (1) to

control the dispersion of the Stiffness and of the Ultimate Strength of the

damping units and (2) to include in the Fatigue Test those parameters which

are most pertinent to the system performance of the damping units in the

building.

NIST NCSTAR 1-1A, WTC Investigation 249
Appendix D

SKILLING - HELLE-CHRISTIANSEN ~ ROBERTSON

Port of New York Authority _ ji , , Attention: Nr. M. P. Levy " 3 " A^r11 *• 3969

1. Draft page A-ll:

a. IXra paragraphs following Eq. 2 shall read as follows:

"The Manufacturing Control Limit for the Loss Factor of nn Acceptance Lot or of a Guarantee l,ot shall he calculated

by substituting the value of S from Eq. 2 and the appropriate

value of the t/Jn from Table I, in Eq. 1."

2. Draft page A-ll:

A. 1.3 Fatigue Test : The requirements of Loss Factor and

Stiffness in 4.1.1 and 4. 1.2 shall also be met for the

100th cycle.

4.1.4 Ultimate Strength : The Ultimate Strength shall be at least 45,000 pounds at 75°F.

3. Draft page A-12:

4.2.2 Stiffness : The average Stiffness at 75°F shall be

greater than (6,000 + 2. OS) but less than (20,000 - 2. OS)

pounds per 0.020" damper deflection, where S is the

standard deviation of the sample calculated from Eq. 2. 4.2.3 Fatigue Test : The requirements of Loss Factor and

Stiffness in 4.2.1 and 4.2.2 shall also be met for

the 100th cycle.

4.2.4 Ultimate Strength : The average Ultimate Strength at

"T5°r shall be at least (45,000 + 2. OS) pounds, where

S is the standard deviation of the sample calculated

from Eq. 2. 4.3.1 Loss Factor : The average Loss Factor shall be at least

0.70.

4.3.2 Stiffness : The average Stiffness at 75°F shall be greater

than (6,000 + 2. OS) but less than (20,000 - 2. OS) pounds

per 0.020" damper deflection, where S is the standard

deviation of the sample calculated from Eq. 2. 4.3.3 Fatigue Test : The requirements of Loss Factor and Stiffness

in 4.3.1 and 4.3,2 shall also be met for the 100th cycle.

4.3.4 Ultimate Strength : The average Ultimate Strength at 75°F

shall be at least (45,000 + 2. OS) pounds, where S is the

standard deviation of the sample from Eq. 2. 5.2.1 General : After the sampled dampers have been tested in

accordance with Section 5.4 and the requirements given in

Section 4.2 have been met, the lot is deemed to have been

accepted by the Engineer. When a lot has been accepted, the

sampled dampers which are not damaged in the testing for

Loss Factor, Stiffness or Fatigue shall be returned to regular inventory. Specimens which have been tested for

Ultimate Strength shall be discarded,

250 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

SKI LLING - H E L L E - C H RISTIANSEN - ROB ERTSON

Port of Row York Authority . .. , »~, ^, m_ u n i ~T - 4 - April A, 29(>9 Attention: Nr. M. P. Levy 1 *

4. Draft pages A-13 and A-14:

5.2.3 (1) Change "Fatigue Loss" to "Fatigue".

(3) Change "Manufacturing Control Limit for that

test" to "Acceptance Requirements In 4.2".

(5) Change "Manufacturing Control Limit" to "Acceptance

Requirements".

(6) Change "Manufacturing Control Limit1

' to "Acceptance

Requirements".

(9) Change "Manufacturing Control Limit" to "Acceptance

Requirements".

5. Draft page A-15:

5.3.1 Delete the sentence, "Lots of dampers having average

values of more than one time in twenty after

three samples." In the last paragraph of 5.3.1 change

"destroyed" to "damaged".

6. Draft pages A-16 and A-17:

5.3.3 (1) Change "at the rate of three for each 160 dampers"

to "at the rate of one for each 50 dampers". Change

"Fatigue Loss" to "Fatigue".

(3), (5), (8), (9) Change "Manufacturing Control Limit"

to "Guarantee Requirements".

5.3.4 Change "prefix" to "suffix".

7. Draft page A-23:

5.4.5.1 \{11), 1(12). Change ..upper case .9 to. lower .case e.

8. Draft pages A-24 and A-25:

5.4.5.2 Fatigue : Delete paragraphs (5) and (6). Add the

following: "(5) Calculate Loss Factor and Stiffness

for the 100th cycle by following the procedures

given in 5.4.5.1,"

9. Draft page A-25:

5.4.5.3 Ultimate Strength : Revise paragraph (1) to read,

"Follow 5.4.2".

10. Draft page A-26:

5.4.5.3 (7) Use these values in calculating the r.r.an and

the standard deviation of the sample.

If you have any question concerning this review, we would be pleased to discuss

the specification with you.

Very truly yours,

SKI LLING , NFLLH , Q1RISTTANSF.N , R0BFRTS0N

Leslie E. Robertson

X>rH e

NIST NCSTAR 1-1 A, WTC Investigation 251
Appendix D

10/6/69

SPECIFICATION

FOR

VISCOELASTIC DAMPING UNITS

CHAPTER ONE

GENERAL CONDITIONS

0.01 GENERAL

This Specification relates generally to the detailing, furnishing

and application of Viscoelastic materials, bonding adhesive, protective

aprons and 1/4" bolts, shims, spring lock nuts, and washers required to

assemble the Components, furnished by others and machined by the Contractor, into Damping Units for the North Tover (Trr_~r A) duu tne South

lower (lower B) of the World Trade Center being constructed by the

Authority in the City of New York.

This Specification requires the doing of all things necessary or proper for or Incidental to manufacture of said Damping Units, as shown

on the Contract Brewings in their present form. In addition, all things

shown on the Contract Drawings even though not expressly mentioned in

this Specification and all things mentioned in this Specification even though not shown on the Contract Drawings are required.

In the event that any requirements of the Specification appear to conflict with the requirements of the Contract Drawings or Contractor's

Shop Drawings, the requirements of the Specification shall prevail.

0.02 WORKMANSHIP AND MATERIALS

Materials and workmanship shall in every respect be in accordance

with the best modern practice and whenever the Contract Drawings, Specification or directions of the Engineer admit of a doubt as to what is

permissible or fail to note the quality of any construction, the interpretation which calls for the best quality construction is to be followed.

Materials shall be new materials and may be purchased from any qualified

source, domestic or foreign, provided they meet the Contract requirements.

252 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

In case of discrepancy between a description or requirement In the Contract Craving* and Specification for any material or equipment

and e catalog number or other designation for the aame material or equipment (even though etated to be acceptable) , the description or requirement a hall control.

The right to use all patented material, compositions of matter,

manufactures, apparatus, appliances, processes of manufacture or types

of construction required in connection with this Contract shall be

obtained by the Contractor without separate or additional compensation whether the sane is patented before, during, or after the performance of the Contract.

0.03 APPROVALS BY ENGINEER

Any approval by the Engineer of any materials, workmanship, plant

equipment, drawings, program, methods of procedure, or of any other

act or thing done or furnished or proposed by the Contractor to be

done or furnished In or in connection with the performance of the

Contract shall be construed merely to mean that at that time the

Engineer knows of no good reason for objecting thereto; and no such

approval shall release the Contractor from his full recpo^rltiiity

fcr the »cc«r«iC« •*« complete performance of the Contract in accor- dance with all the terms thereof.

0.04 ERRORS AND DISCREPANCIES

If, in the performance of the Contract, the Contractor discovers

any errors or omissions in the Contract Drawings or Specification, or in the work undertaken and executed by him, he shall immediately notify

the Engineer and the Engineer shall promptly verify the same. If with

the knowledge of such error or omission and prior to the correction

thereof, the Contractor proceeds with any work affected thereby, he

shall do so at his own risk and the work so done shall not be considered as work done under and in performance of this Contract unless and

until approved and accepted.

0.05 PATENTS

The right to use all patented materials, composition of matter,

manufactures, apparatus, appliances, processes of manufacture, or types

Page 2

NISTNCSTAR 1-1 A, WTC Investigation 253
Appendix D

of construction as part of the sale shall be obtained by the Vendor

without separate ot additional compensation vhether the aone is

patented before, during, or after the performance of thU Contract.

0.G6 INSPECTIONS

Testing and storage operations in connection with this Contract

shall be at all times and places subject to the inspection of the

Engineer, acting personally or through his Inspectors.

The Contractor, at his own expense, shall furnish auch reasonable

facilities and give such assistance for inspection as the Engineer nay

direct. The Contractor shall secure for the Engineer and his Inspectors

free access to those parts of factories, plants or warehouses in which

such testing and storage operations are conducted and shall give at

least ten days' notice to the Engineer of his Intention to cotnm*nrA

initial acceptance and five year testing and recommencement after any

suspension of testing of more than a week.

0.07 mo CQSriSSTTIAL BISiLUSUKES - PROPERTY of AUTHORITY

The Contractor agrees that all information of any nature whatsoever, regardless of the form of the communication, received from the

Contractor (including its officers, agents or employees) by the Authority,

its Commissioners , officers, agents, employees, or consultants, and

notwithstanding any statement therein to the contrary, has not been

given in confidence and may be used or disclosed by or on behalf of the

Authority without liability of any kind except as may arise under letters

patent of the Contractor, if any.

All drawings, data, and other papers of any type whatsoever,

whether in the form of writing, figures or delineations, uhich are specifically prepared and required in the performance of this

Contract and submitted to the Authority shall become the property

of the Authority. The Authority shall have the non-exclusive right

to use or permit the use of all such drawings, data and other

papers and any ideas or methods represented thereby for any purpose

shall be deemed to have been given in confidence. Any statement

or legend to the contrary in connection with such drawings, data

or other papers and in conflict with the provisions of this paragraph shall be void and of no effect.

Page 3

254 NIST NCSTAR 1-1A, WTC Investigation
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0.08 CONTRACT DRAWINGS

The Contract Drawings which accompany and form part of this

Specification are separately numbered and entitled aa follows:

DRAWING

NUMBER

DA-1

DA-2

DA-3

DRAWING TITLE

Damping Unit - Structural Tees

Damping Unit - Structural Bars

Viscoelastic Damping

ORIGINAL

DATE

9-16-66

9-16-66

10-27-67

REVISED

DATE

8-29-69

8-29-69

5-20-69

The Contract Drawings do not show all of the details of the

Materials and are intended only to illuBUi.«La tlis character

tent of Materials. Accordingly, they may he supplemented during

the performance of the Contract by the Engineer, or by the contractor

subject to the approval of the Engineer, Co the extent necessary to further illustrate the Materials.

In the event that any requirements of the Contract Drawings conflict with the requirements of the Contractor's Shop Drawings, the

requirements of the Shop Drawings Bhall prevail.

After the Contract has been executed, the Contractor will be

furnished with one set of sepias of the Contract Drawings without

chBrge.

0.09 PORTION OF MATERIALS SHOWN ON CONTRACT DRAWINGS, TO BE DETAILED,

FURNISHED, MACHINES . ASSEMBLED AND DELIVERED UNDER THIS CONTRACT

A. ITEMS TO BE INCLUDED IN THIS CONTRACT

1. Machining of Components furnished by others consisting

of structural tees and bars.

Page A

NISTNCSTAR 1-1A, WTC Investigation 255
Appendix D

2. Application of protective aprons to the viscoelsatic material, bonding adhesive and viscoclaatic material to the tee flange face and both

aide* of the nominal 4" x 1/2" bar to the thickness and lengths specified under this Contract.

3. The assembly of two tees and one bar into Damping

Units after application of the Vlacoclastie

material using shims and 1/4" bolts, spring lock

nuts, and washers to be furnished by the Vendor

under this Contract.

4. The shipping and bundling of completed Damping

Units on wood skids used for delivery of steel

components segregated as to type of Damping Units.

Each bundle to contain approximately 104 Type

"A" or 104 Type "B" Damping Units and to be

marked in accordance with detailed instructions

from the Engineer.

5. Tests in accordance with the Contract.

B. ITEMS NOT TO EE FURNISHED OR PERFORMED BY VENDOR

1. Structural tees and bars.

2. Field bolts in web of tee and field bolts

in end of 4" x 1/2" nominal bar.

3. Fainting of Damping Unite.

4. Installation of Damping Units in Towers of

The World Trade Center.

0.10 COMPONENTS FURNISHED BY OTHERS

A. The Components consisting of the structural tees and bars shown

on the Contract Drawings will be fabricated by others from steel

conforming to ASTM A 36 - 63T or ASTM A 572, Grade 42.

B. Fabrication tolerances on Components will conform to the re- quirements of the AISC Specification adopted April 17, 1963

entitled "Specifications for the Design, Fabrication, and

Erection of Structural Steel for Buildings" as supplemented

by the specific requirements contained in the Contract Drawings,

Specification and paragraphs C, D, and E of this numbered clause.

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256 NISTNCSTAR 1-1A, WTC Investigation
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C. STRUCTURAL TEES - SPECIAL REQUIREMENTS

(a) No deviation from absolute flatness in excess of

1/32 inch over the entire flange surface.

(b) No deviation Iron absolute flatness in excess of

1/32 inch over the 4 inch extended area of the web.

(c) No deviation from perpendicularity of the 4 inch

extended area of the web to the area to be

machined in excess of 1/32".

(d) No deviation from perpendicularity of the entire area of the web to the area to be machined in excess of 1/16 inch.

(e) The A inch extended area of the web shall be parallel within

1/16 inch to che two center lines of the 1/2

inch diameter holes extending in the lengthwise

(12 inch) direction of the area to be machined.

(f) Holes for erection bolts and assembly Dolts

accurately located as shown in the Drawings.

(g) Each piece free of loose and unbroken bubbles

of mill scale, loose rust, dirt, and other

foreign material.

(h) No trade marks of any type whatsoever shall be used.

D. STRUCTURAL BARS - SPECIAL REQUIREMENTS

(a) No deviation from absolute flatness in excess of

1/32 inch over entire surface of each side.

(b) Holes for assembly bolts accurately located as shown in the Drawings.

(c) Each piece free from loose and unbroken bubbles

of mill scale, loose rust, dirt, and other

foreign material.

(d) No trade marks of any type whatsoever Bhall be used.

E. CERTIFICATION

On all components furnished by others, certification shall

be provided to the contractor that all the requirements of this

clause and the Contract Drawings 6 Specification have been met.

Page 6

NISTNCSTAR 1-1A, WTC Investigation 257
Appendix D

CHAPTER TWO

TECHNICAL REQUIREMENTS

1.0 GENERAL

The Contractor referred to In this Specification is the Minnesota

Mining and Manufacturing Company.

The Engineer referred to in this Specification la defined under

clause numbered 2 of the Contract entitled "Definitions".

2.0 MATERIALS

2.1 VISCOELASTIC MATERIAL

3M Brand Vibration Damping Elastomer, Y-9274, aa produced by

Minnesota Mining and Manufacturing Company, is approved for use in

fsbr^stina viscoelastic Damping Unite . Other viscoelastlc materials

suitable for such fabrication may also be submitted tor approval by

th* En«*n**>T. Tha request for approval of other viscoelastic materials

shall be accompanied by full technical data on the material, including

documentation of performance characteristics of the actual viscoelastic

Damping Units proposed for use in the work. In any case, however, and

notwithstanding the above stated approval for said 3M brand or any

Engineer's approval for any other material, whatever material is used

shall be considered satisfactory under this Contract only if it meets

all the requirements of this Contract in addition to the requirements

of this paragraph.

2.2 STEEL

Viscoelastic Damping Units will be fabricated from tees and bars

furnished by others using the Contract Drawings listed under clause

numbered 0.08 entitled "Contract Drawings" and Contractor's Shop

Drawings listed in Section 2.4 of this numbered clause.

2.3 1/4" DIAMETER ASSEMBLY BOLTS

All 1/4" diameter assembly bolts used in the work shall conform

to ASTM A-307 "Standard Specification for Low-Carbon Steel Externally

Page 7

258 NIST NCSTAR 1-1A, WTC Investigation
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and Internally Threaded Standard Fasteners". ASTM A-307 bolts shall

be tightened until the spring lo<* are partially compressed. All

washers shall be flat, smooth and conform to the dimensions and

properties required in the Drawings and applicable Specifications.

2.4 CONTRACTOR'S SHOP DRAWINGS

The following Contractor's Shop Drawings are approved for fabrication of viacoelastic Damping Unite:

DRAWING NUMBER DESCRIPTION DATE

12-2435-0001-9

12-2435-0002-7

12-2435-0011-8

12-2435 -O015-9

Damper Assembly Type A

Damper Assembly Type B Structural Tee Mill Spec,

Mill Spec."

Structural Bar Type B Kill Spec.

September 3,

September 3,

September 3,

September 3,

1969

1969

1969

1969

September 3, 1969

2 . 5 BONDING ADHESIVE

Scotchweld Brand Structural Adhesives EC 1614 and 3520 as produced

by Minnesota Mining and Manufacturing Company are approved for bonding

the viscoelastic material to the steel surfaces.

2.6 PROTECTIVE APRONS

Scotch Brand Pressure Sensitive Tape #465 as produced by Minnesota

Mining and Manufacturing Company is approved for protective aprons at

the ends of the viscoelastic material.

3 . 0 DEFINITION OF TE RMS

3.1 DAMPER PERFORMANCE

Page 8

NISTNCSTAR 1-1A, WTC Investigation 259
Appendix D

3.1.1 FIXED CONDITIONS NOMINAL VALUES

t1T

f

w

v.e,

1 temperature

> displacement amplitude

thickness of each

vlscoelaatlc slab

frequency

> maximum shear strain

» width of each viscoelastic slab

* bonded length of each

viscoelaBtic slab

vi8coelastic shear area

V - volume of viscoelastic

material

75* + 3'F.

0.020"

0.050"

0.1 cycle per sec.

0.4 inches/inch

4.0"

10.0"

2WL - 80 sq. in.

2WLT 4 cu. in.

3.1.3 MEASURED PARAMETERS

F * stiffness one-half of the double amplitude

of the axial force in the damper subjected to a sinusoidal displacement with an amplitude of

0.020 inch at 0.1 Hz

A^ > area of hysteresis loop

lbs. /0. 020"

inches2

ultimate Strength is that axial compressive force, expressed in

pounds, on the ends of the damper necessary to cause shear failure

of the viscoelastic bonded area when the force is applied at a rate

of 0.5 inch per minute.

3.1.4 CALCULATED PARAMETERS

s » Shear Stress

G* • Complex Shear Modulus

G" - Loss Shear Modulus

G' " Elastic Shear Modulus

lbs. /inch •

2 lb8./inch

lbs. /inch

lbs. /inch »

S

[ <G*)

2-<G") 2

] 1/2

Page 9

260 NISTNCSTAR 1-1A, WTC Investigation
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D - Loss Factor - C"

G'

3.2 REQUIREMENT AVERAGE

The Requirement Average is the limiting average value of the

specified parameter determined from a given sample at set forth in

the equations given for each parameter.

The subscript i stands for an individual damper. n * the number of dampers in the sample under consideration.

k - the number of accepted lota.

The symbol 9* stands for the standard deviation accumulated over all

test dancer a.

The standard deviation CT^ is defined by the working equation:

1/2

EQUATION 1

Where the Requirement Average is the basis for Acceptance the

standard deviation for the first lot shall be calculated from a special

group of ten dampers that is made and tested exactly as the dampers

comprising the first 'Acceptance lot.

The standard deviation for all subsequent Acceptance lots shall

be continuously and cumulatively adjusted by pooling the standard

deviations of the accepted lots by Equation 2. \i/2

<r

2 t»i - » \ * » j EQUATION 2 6 pooled ^

(n . - i)

J

The Requirement Average for the first 5 Year lot, for each applicable parameter, shall be calculated using the completely pooled

standard deviation of all Acceptance lots.

Paoe 10

NISTNCSTAR 1-1A, WTC Investigation 261
Appendix D

The Requirement Average for all subsequent S Year lots shall

be continuously and cumulatively adjusted by pooling the standard

deviation of all Acceptance lots with the standard deviations of

all accepted 5 Year lots by Equation 2.

4.0 REQUIREMENTS

4.1 ACCEPTANCE REQUIREMENTS

All requirements must be met

4.1.1 LOSS FACTOR

Requirement Average - 0.7 + 0.9480X when n • 5 Requirement Average • 0.7 + 0.670c£ when n - 10

Requirement Average - 0.7 + 0.54/bc when n • 15

4.1.2 STIFFNESS

6000 + 1.25CJ -sUU^uJUsuaent Average < zu.uuu - i.iSa^vnen n • 5 6000 + 1.25«£< "

M < " "ff;when n - 10

6000 + 1.25Cj< " " < " " d "hen n - 15

4.1.3 ULTIMATE STRENGTH

Requirement^ > 40,000 at 75*F. when n • 5 If 0 or 1 damper falls th» lot Is accepted

If 2 fall take a second sample of 5 dampers

All must pass •

4.1.4 FATIGUE TEST The stiffness requirement shall become:

5400 + 1.250£ Requirement Average< 22,000 - 1.25C£ when n - 5 5400 + 1.25CC< Requirement Average < 22,000 - 1.2XZ "hen n - 10

5400 + 1.25«3£^Requirement Average < 22,000 - i.25<7£ when n - 15

4,2 FIVE YEAR REQUIREMENTS

4.2.1 LOSS FACTOR

Requirement Ave. - 0.63 + 0.948<J£ , when n - 10

Requirement Ave. » 0.63 + 0.670fl£ , when n - 20

Requirement Ave. • 0.63 + 0.54?G£ , when n - 30

Page 11

262 NIST NCSTAR 1-1A, WTC Investigation
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4.2.2 STIFFNESS

5400

5400

5400

+ l,25fl£< Requirement Ave. <T 22,000 - 1.250^ when n » 10 + 1.25<JX< " " < "

(ft when n « 20

+ 1.25c£< " " < "o^ when n - 30

4.2.3 ULTIMATE STRENGTH

Requirement* > 36,000 at 75'F. vhen n - 13. If 0, 1, 2, or 3 dampers fail the lot is accepted. If 4 fail take a second sample

of 13 dampers. All must pass.

5.0 QUALITY ASSURANCE

5.1 ACCEPTANCE

5.1.1 GENERAL

After the sample datnnoro H»v« berr. tested in acccrUoiiuw wlL'n Section 5.3 and the requirements given in Section 4.1 have been

met the Acceptance let, as defined below, 1b deemed to have been

accepted by the Engineer.

When a lot has been accepted, the sample dampers not damaged

in testing shall be delivered to the Authority.

5.1.2 LOT

An Acceptance Lot shall consist of all dampers made in each

calendar week from the same lot of viscoelastic material by the same process and to be submitted for Acceptance testing at one time.

5.1.3 SELECTION OF SAMPLES

5.1.3.1 Loss Factor, Stiffness & Fatigue

(1) Dampers shall be selected from each Acceptance Lot st random at the rate of three per day until the lot is

complete

.

(2) Test one-third of these dampers for Loss Factor,

Stiffness, and Fatigue in accordance with Section 5.3.

?age 12

NISTNCSTAR 1-1A, WTC Investigation 263
Appendix D

(3) If the averages of the test results meet the Acceptance

Requirements , the lot is accepted for theae requirements.

(4) If the average of the teat results for any of the testa

does not meet the Acceptance Requirements in Section 4.1,

take another third of the dampers selected under (1) and

test them in accordance with Section 5.3 for the failed

requirements.

(5) If the averages of the test results for the original group

and second group of samples meet the Acceptance Requirements, the lot is accepted for these requirements.

(6) If the average of the test results for any of the tests

of the original and second group of samples does not meet

the Acceptance Requirements, take the last third of dampers

selected under (1) and test them in accordance with Section

S.3 for the failed requirements.

(7) If the averages of the test results for the original, second

and third groups of samples meet the Acceptance Requirements,

the lot is accepted for these requirements.

(8) If the average of the test results for any oz the tests o£

the original, second, and third group of samples does not

meet the Acceptance Requirements, the lot is rejected.

5.1.3.2 ULTIMATE STRENGTH

(1) Dampers shell be selected from each Acceptance lot at random

at the rate of two per day until the lot is complete.

(2) Test one-half of these dampers for Ultimate Strength in

accordance with Section 5.3.

(3) If the individual teat results meet the Acceptance Requirements the lot is accepted for this requirement.

(4) If the individual test results do not meet the Acceptance

Requirements take the other half of the dampers selected

under (1) and test them in accordance with Section 5.3.

(5) If the individual test results for the original and second

groups of samples meet the Acceptance Requirements the lot

is accepted for this requirement.

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264 NISTNCSTAR 1-1A, WTC Investigation
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(6) If the individual test results of the original and

second group of samples do not meet the Acceptance

Requirements » the lot is rejected.

5.1. A IDENTIFICATION

All dampers shall be permanently imprinted with an identification code of the type shown below:

ALL DAMPERS ACCEPTANCE TEST HAMPERS

DAMPER PDTN. YEAR DAY

SUFFIXED

TYPE LOT g

A 2 7 174 A

The letters and numerals shall be between 1/4" and 1/2'

in height and shall be located in a uniform manner. The

identification shall be imprinted once on the exposed

surface of the web of each structural tee.

TTCTTM/;

5.2.1 GENERAL

Not less than 5 years nor more than 5 years and 3 months after

all the dampers in a given 5 Year lot have been manufactured* the

samples selected frcs that let and stored by the Contractor shall

be tested. Dampers for 5 Year tests shall be stored by the Contree tor in conformance with conditions given in Section 5.3.

After the samples from a 5 Year lot have been tested in

accordance with Section 5.3 and the requirements given in Section

A. 2 have been met, the lot is deemed to have passed the 5 Year test.

When a 5 Year lot has been accepted, the sample dampers not

damaged in testing shall be delivered to the Authority.

5.2.2 LOT

A 5 Year lot shall consist of one-fourth of the total number

of accepted dampers in this Contract, there being four such lots

and each being selected as the first, second, third, and last

fourth, in sequence of manufacture.

NISTNCSTAR 1-1 A, WTC Investigation 265
Appendix D

5.2.3 SELECTION OF SAMPLES

5.2.3.1 Loss Factor and Stiffness

(1) Dampers shall be selected from each 5 Year lot at random

at the rate of one for each 160 dampers produced until a total of 30 from each lot is reached. Test specimens

shall be selected from Type A dampers only.

(2) Test one-third of these dampers for Loss Factor. Stiffness

and Fatigue according to Section 5.3.

(3) If the averages of the test results meet the 5 Year

Requirements, the lot is accepted for these requirements.

(4) If the average of the test results for any of the tests

HficB i\r>t m»»f rh; 5 V««w ""•f»^«-*- £- SCCtiiu A.

2

take another third of the dampers selected under (1) and

test thee in accordance with Section 5.3 for the failed

requirements.

(5) If the averages of the test results for the original

Requirements, the lot is accepted for these requirements.

(6) If the average of the test results for any of the tests

of the original and second group of samples does not

meet the 5 Year Requirements, take the last third of

camper* selected under (1) and test them In accordance

with Section 5.3 for the failed requirements.

(7) If the average of the test results for the original,

second and third groups of samples meet the 5 Year

Requirements the lot is accepted for these requirements.

(8) If the average of the test results for any of the tests of the original, second and third group of samples does not meet

the 5 Year Requirements, the lot is rejected.

5.2.3.2 ULTIMATE STRENGTH

(1) Dampers shall be selected from each 5 Year Lot at random

at the rate of 1 for each 200 dampers produced until a total of 26 from each lot is reached. Test specimens

shall be selected from Type A dampers only.

Page I5

266 NIST NCSTAR 1-1A, WTC Investigation
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(2) Teat one-half of these dampers for Ultimate Strength

in accordance vith Section 5.3.

(3) If the individual teat results meet the 5 Year Re- quirement*, the lot la accepted for this requirement.

<4) If the individual teat reaults do not meet the 5 Year

Requirement* , take the other half of the damper?

selected under (1) and test them in accordance with

Section 5.3.

(5) If the individual test results for the original and

second groups of samples meet the 5 Year Requirements

,

the lot Is accepted for this requirement.

(6) If the individual test results of the original and

second group of samples do not meet the 5 Year Requirements, the lot is rejected.

5.2.4 IDENTIFICATION

Guarantee test dampers shall be identified aa in

Section 5.1.4 except that the suffix "A" »1>*11 be rc- plscei vith a number, one through four, corresponding

to the Guarantee Lot number and the capital letter "G".

5.3 TEST METHODS

5.3.1 STEEL FAILURE

If the steel components

of the tests that test may be

test specimen substituted for

of a damper deflect during any

declared no test and another

it.

5.3.2 CONDITIONING

All test dampers shall be maintained at 303 relative

humidity and 75*F. + 3*F. from the time of manufacture until

the tine of testing.

5.3.3 TESTING TEMPERATURE

All teats shall be conducted at a temperature of 75*F. +

3*F. as determined by a thermocouple inserted in an edge of the

viacoelastic damping material. Record the test temperature.

The dampers shall have been in a temperature of 75 °F. + 3°F.

for at least eight hours before testing.

Page 16

NIST NCSTAR 1-1A, WTC Investigation

267
Appendix D

5.3.4 REPORTINC VI SCOELASTIC WIDTH

The measured values of Stiffness, hysteresis loop area (A^)

and Ultimate Strength shall be corrected for a common bonded viacoelastic width of eight inches by uaing the multiplying factors listed

in Table 1 belov:

TABLE I

IF BONDED WIDTH OF MULTIPLY THE TEST RESULTS OF STIFFNESS

VISC0E1ASTIC SLAB IS & ULTIMATE STRENGTH BY 7-6/16" 1.085

7-7/16" 1.076

7-8/16" 1.067

7-9/16" 1.058

7-10/16" 1.049

7-11/16" 1.040

7-12/16" x.uyz

2-13/16" 1.024

7-14/16" 1.016

7-15/16" 1.008

6" 1.000

8-1/16" .992

8-2/16" .984

5.3.5 REPORTING TEMPERATURE FOR STIFFNESS

The corrected results of Stiffness determined in Section 5.3.4 shall

be further corrected for a common temperature of 75 *F. by adding the

product of the temperature difference and the temperature coefficients

listed in Table II below:

TABLE II

IF TEST TEMPERATURE (°F) IS

72.0

72.5

73.0

73.5

74.0

74.5

75.0

75.5

76.0

76.5

77.0

77.5

78.0

USE TEMPERATURE COEFFICIENT

(lbs./°F) OF

-865

-880

-900

-935

-1000

-1000

+1000

+1000

+1065

+1100

+1140

+1165

Page 17

268 NISTNCSTAR 1-1A, WTC Investigation
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5.3.6 TEST PROCEDURES

Where more than one test is perforoed on the aame damper,

they shall be conducted in the order given in this section*

5.3.6.1 Loss Factor & Stiffness

(1) Bolt an assembled damper in the special jaws attached

to the test machine. Use nev high tensile steel bolts

for each test specimen.

Use 1" diameter ASTM A490 bolts for attaching the tee

end of the damper and 7/8" d> A-490 bolts (Type A

units) or 1 l/4 n $ A-490 bolts (Type B units) for

the bar end. Tighten all nuta until all four j ewe and the specimen are firmly together, then tighten

each nut an extra one-half turn.

(.2; Bolt the micrometer head to one or the T-sections or the damper using previusly drilled holes. Bolt the arm holding the extensometer to the central bar of

the damper. See Figure 1 .

(3) Connect the output of the extensometer to the X-Y

chart recorder.

(4) After calibrating the system and determining there is no static force bias on the damper, set the test

machine on strain control and apply sinueoidal deformation to the viacoelastic layers by alternating

tensile and compressive axial force on the ends of

the damper with a period of 10+0.5 seconds. The

force on the ends of the damper shall be sufficient

to produce a shear displacement amplitude of 0.020"

in the vis cc elastic damping layers. A typical

hysteresis loop is shown in Figure II.

NISTNCSTAR 1-1A, WTC Investigation

Page 18

269
Appendix D

FIGURE I

Genor*! Sketch of Test Set up

F/2 F/2

V.E.

n

MICROMETER HEAD

L.V.D.T.

(Extenaomoter)

1

p. 19

270 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 5

A TTPIC1L HSTERSS23 U>OP

UTERSIGi

LOAD

p. 20

NIST NCSTAR 1-1 A, WTC Investigation 271
Appendix D

(5) Record the value of F from the X-Y chart recorder.

(6) Calculate results from Step (5) to a common vis co- elastic width of 8" following the procedure given

in 5.3.4 and record separately.

(7) Calculate results from Step (6) to a common temperature of 75 *F. according to the procedure given in

5.3.5. Use these values in calculating the Requirement Average according to the procedure given in 3.2.

(8) Measure the bounded area of the hysteresis loop with

a planiooter

.

(9) Calculate the results from Step (8) for a common viscoelastic width of 8" following the procedure

given in 5. 3. A and record separately.

***** — *• * ... •» - _ _ r<» — ««u jr.,. _

\ i.U J VCJ.tUJ.tlLC LUC LUOO MUSK. ."»«U4.U» , v» » ItVM

G" - \C

1

C

2

using the values of from Step (9)

(U) Calculate the shear stress, s, from

F

Ve.

using the values of F from Step (6).

(12) Calculate the complex shear modulus, G*, from

G* • sV

(13) Calculate the Elastic Shear Modulus, G* , from

G' - I (G*)

2 - (GM

) 2] 1/2

(14) Calculate Loss Factor, D, from

G"

D «•

Use these values in calculating the Requirement Average

according to the procedure given in 3.2.

Page 21

272 NIST NCSTAR 1-1A, WTC Investigation
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5.3.6.2 FATIGUE TEST

(1) Measure and record the temperature of the viacoelastic

material Immediately before starting the Fatigue Loss

measurements

.

(2) Following the detailed procedures given in Section

5.3.6.1 run 99 successive cycles of the hysteresis

loop (Loss Factor and Stiffness) test.

(3) Return the damper to the temperature measured under

(1) + 1*F.

(4) Run the 100th ' cycle as in (2).

(5) Following the procedures given in 5.3.6.1 calculate

Stiffness^foz. the. 100th * cycle.

5.3.6.3 ULTIMATE STRENGTH

(1) Follow 5.3.3.

(2) Bolt an assembled damper in the special jaws attached

to the test machine. Use new high tensile steel bolts

for each test. Use 1" diameter ASTM A 490 bolts for

attaching the tea end of the damper and 7/8" diameter

A-490 bolts (Type A units) or 1 1/4" diameter A 490

bolts (Type B units) for the bar end. Tighten all

nuts until all four jaws and the specimen axe firmly

together, then tighten each nut an extra 1/2 turn.

Remove the four assembly packaging bolts. Do not

remove shims

.

(3) Set the test machine on lineal deformation control at a speed of 0.5"/min. and apply a compressive load axially

to the ends of the damper until shear failure of the

viBcoelastic bonded area occurs.

(4) Use the X-Y chart recorder to make a continuous permanent

record of the load-deflection relationship.

(5) Record the maximum load shown on the chart.

(6) Calculate results from Step (5) for a common viacoelastic

width of 8" following the procedure given in 5.3.4. 'This

is the Ultimate Strength.

Page 22

NISTNCSTAR 1-1A, WTC Investigation 273
Appendix D

This page intentionally left blank.

274 NISTNCSTAR 1-1A, WTC Investigation
Appendix E

Supporting Documents for Chapter 6

This appendix contains the supporting documents that are referenced in Chapter 6 of this report. All of

the documents contained in this appendix are reproduced with permission of The Port Authority of New

York and New Jersey. Table E-l contains a summary of supporting documents and their location within

this appendix. The footnote numbers given in the table correspond to those in Chapter 6. Documents in the table without footnote numbers are referenced in the main body of Chapter 6.

Table E-1. Supporting documents for Chapter 6.

Footnote Number Document Title Page(s)

Section 6.3.1 - Floor Trusses

Fabrication and inspection requirements from the contract between the Port Authority and Laclede

Steel Company for the floor trusses used in WTC 1 and WTC 2 (WTCI-71-I) 276

Section 6.3.2 - Box Core Columns and Built-up Beams

Fabrication and inspection requirements from the contract between the Port Authority and Stanray

Pacific Corporation for the box core columns and built-up beams used in WTC 1 and WTC 2 (WTCI-244-L)

299

1 Letter dated June 5, 1967 from Leslie E. Robertson of SHCR to Malcolm P. Levy of PONYA

(WTCI-491-L)

309

Draft contract between United States Testing Company and PONYA dated August 25, 1967 (WTC1-493-L; first page of the contract and Appendix 1 of this document] 319

3 Letter dated April 5, 1967 from Leslie E. Robertson of SHCR to Malcolm P. Levy of PONYA

(WTCI-489-L)

325

4 Letter dated September 21 , 1967 from R. M. Monti of PONYA to R. E. Morris of the Stanray Pacific Corporation (WTCI-490-L)

330

5 Letter dated November 13. 1967 from R. M. Monti of PONYA to R. E. Morris of Stanray Pacific Corp. (WTCI-498-L)

332

Section 6.3.3 - Exterior Hallfrom Elevation 363 ft to the 9th Floor Splice

6 Letter dated October 21. 1966 from PDM to James R. Endler of Tishman Realty and Construction Company Inc. (part of WTCI-745-L: second page and enclosure appears to be missing)

335

Amendments made to initial quality control program submitted to PONYA by PDM (parts of WTCI-744-L)

336

PDM specifications for welding procedures (parts of WTC1-741-L) 347

8 Letter dated October 4. 1967 from R. M. Monti of PONYA to H. M. Fish of PDM (WTC1-745-L) 364

Section 6.3.4 - Exterior Wall Above 9th Floor Splice

Fabrication and inspection requirements from the contract between the Port Authority and Pacific Car

and Foundry Co. for the exterior walls used in WTC 1 and WTC 2 (WTC1-242-L)

366

9 Letter dated July 8, 1967 from R. C. Symes of Pacific Car and Foundry to R. M. Monti of PONYA

(part of WTCI-748-L)

372

10 Letter dated July 13, 167 from James White of SHCR to R. M. Monti of PONYA (part of WTCI-748-L)

373

Section 6.3.5 - Rolled Columns and Beams

Fabrication and inspection requirements from the contract between the Port Authority and MontagueBerts Company. Inc. for the rolled columns and beams used in WTC 1 and WTC 2 (WTCI-243-L)

379

NISTNCSTAR 1-1A, WTC Investigation 275
Appendix E

THE WORLD TRADE CENTER Page 3-01

CHAPTER THREE

FABRICATION OF STRUCTURAL STEEL

ill GENERAL

301.100 Structural steel shall be fabricated complete as shown in the

Drawings and in approved details shown in the shop drawings.

301.200 The steel furnished for each location shall have a minimum

yield point equal to that scheduled in the Drawings, and shall

be selected from the applicable steel specifications listed in

Chapter Two, MATERIALS.

301.300 All steel shall be ASTM A36 for locations where a specific

Strength requirement is not stated in the Drawings.

«2 IDENTIFICATION

302.100 The Contractor shall identify all steel which will be used in

the work beginning at the mill and shall maintain identification

at all times thereafter including during fabrication. The method

used shall make both the grade and yield point of the steel

readily identifiable. Identification shall be maintained after

fabrication.

302.200 The Contractor shall identify each member or assembly with a system

of marks. Each mark shall be clearly indicated in the shop drawings.

The system of identification marks for fabricated structural steel

shall be a permanent system such as stamping and be approved by the Engineer

In addition, the contractor shall paint erextion marks on each piece.

276 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Pag>- 3-02 THE WORLD TRADE CENTER

SPECIFIC REQUIREMENTS

.03.100 Flane cutting by hand shall cot be performed without the

Engineer's approval. Handcut surfaces shall be made smooth

by chipping, planing or grinding.

303.200 Fabricated material containing sharp kinks or bends shall be

rejected. Material straightened prior to fabrication shall

be carefully examined for signs of distress or other defects

before being placed in fabrication. Distressed or otherwise

defective material shall not be used in the work.

303.300 Where required by the Contract Documents, surfaces shall be

milled, or finished by other approved means. All finishing

shall be clearly shown in the shop drawings.

303.400 Bolt holes and similar holes shall be punched, drilled, subpunched or sub-drilled and reaned, and shall not be :nade or

enlarged by gas cutting.

303.500 Holes retired by the Erector, and shown on the Drawings prior

to approval of Shop Drawings shall be furnished without cost.

NISTNCSTAR 1-1A, WTC Investigation 277
Appendix E

6/66 TEE WORLD TRADE CENTER Page 3-03

ft FABRICATION TOLERANCES

304. 100 Fabrication tolerances shall conform to the requirements of the

AISC Specification and AWS D1.0, as supplemented by specific

requirements contained in the Drawings and Specifications, In no

case shall tolerances exceed those obtainable by the best modem

shop practice.

SPECIAL REQUIREMENTS

Floor trusses shall be fabricated to fall within the tolerances

listed belov:

1. Camber at midspan +3/8 inch

2. Deviation from design depth + 1/4 inch

3. Longitudinal deviation of panel point along chord + 1/4 inch

4. Vertical deviation of panel point from longitudinal axis + 1/4 inch

5. Deviation in over-all length + 3/8 inch

6. Maximum sweep (in inches) over-all length (in feet) 40

278 NISTNCSTAR 1-1A, WTC Investigation
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Page 1-11

THE WORLD TRADE CENTER

05 QUALITY CONTROL AND INSPECTION :

105.100 Supervision and Inspection

All fabrication and welding of floor trusses shall be

subject to continual visual inspection, surveillance and

supervision by responsible, qualified Contractor's supervisory personnel. These personnel will check for dimensional

conformance to applicable details, proper manufacturing

procedures, correct settings of automated controls, and will

ensure that required weld strengths and specified quality of

all finished material fabricated under this Contract conforms

to the Specifications and to this Quality Control Program.

105.101 Material Test Reports

With minor exceptions, all steel employed in the fabrication

of trusses will be produced in the furnaces and mills of The

Contractor. A copy of each applicable certified mill test

report showing heat number, chemistry, and physical properties

for all steel truss components will be transmitted to The

Engineer and to S-H-C-R by the Contractor, regardless of the

source of the material.

105.102 Resistance welding

All interior truss panel points will be connected by

electronically controlled resistance welding designed to

provide a minimum of two times the strength of the connected

members at full design load.

All angle chords will be cleaned by shot blasting to

ensure that contact surfaces are scale-free prior to production

line resistance welding.

NISTNCSTAR 1-1A, WTC Investigation 279
Appendix E

Page 1-12

THE WORLD TRADE CENTER

All production line panel point welds will undergo "on-line"

non-destructive testing by hydraulic wedge action testers which apply

pre -determined, accurately measured test forces. The force applied by the

wedge action tester will subject the welds tested to a minimum force across

the welds of 2.25 times the calculated design force carried by the highest

loaded member at the subject joint. The wedge action testing device is

arranged so that the test force is applied to the two welds on one side of

each panel point, resulting in mechanical inspection of SO?, of all production

line welds.

In addition, production line panel point welds on completed trusses

vill be spot-checked by vertical double shear tests. These spot-check tests

will include the first completed truss in each run of a given style and a

minimum of one truss for each 200 trusses in a run of a given style. Panel

point welds will be subjected to test loads equal to or exceeding two times

the summation of the design forces in all members at the subject joint. In

trusses selected for vertical double shear tests, each joint in the truss will

be tested. All trusses passing vertical double shear tests will be returned

Into the production line and incorporated into the work.

All panel point welds failing either the wedge action test or the

double shear test will be repaired by adding hand welded fillet welds at all

four chord-web intersections at each applicable panel point. Repair arc

"elding will be under the supervision and surveillance of supervisory personnel

'ho are certified welders in accordance with Appendix D, Part II Welder

Salification, of AWS Dl.O-66. All repair welds will be subjected to the

double shear test. Repair velds which fail to provide a minimum of two times

: *ie calculated design strength of the connected members will be rejected.

280 NISTNCSTAR 1-1A, WTC Investigation
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Page 1-13

THE WORLD TRADE CENTER

Full scale load tests will be performed on completely fabricated

u russ components. A minimum of one load test will be made for each identified

truss style designated on Design Data Sheets D105-T1 through D105-ET10, inclusive (see Pages 0-11 and 0-12). Test loads will be applied by hydraulic

loading in a test frame designed for this purpose. Load will be measured by

electric load cells and center span deflection will be checked by dial gages.

Deflection and recovery data will be measured and recorded for each increment

of load application or removal for at least one load test of each style referred

to above. Deflection at design load and maximum applied load will be recorded

for all load tests. One copy of the report of each load test, whether

successful or unsuccessful, will be forwarded to The Authority.

105.103 Physical Tension Tests

Tension tests on truss components, chord angles, and

webs will be performed at random on selected sample members

included in the normal truss fabrication. Reports of these

tests will be forwarded to the Engineer and to S-H-C-R.

105.104 Marking

All trusses will be subjected to final inspection by

The Contractor's Quality Control personnel. Trusses which

conform to the requirements of the foregoing Quality Control

and Inspection program and to the Specifications will be

marked by a painted erection mark for each type of truss.

Identification tags will be affixed to each truss or each

bundle of trusses of the same style and erection mark

105.105 Access to Plant

Free access to the plant of the truss manufacturer and

NISTNCSTAR 1-1A. WTC Investigation 281
Appendix E

Page 1-14

THE WORLD TRADE CENTER

the available inspection and test facilities will be

offered the qualified inspectors representing the Authority

for observation of the test and inspection procedures

outlined herein.

105.106 Additional or Extra Tests

Any testing requested beyond that identified herein

shall be for the account of the Authority.

282 NISTNCSTAR 1-1A, WTC Investigation
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THE WORLD TRADE CENTER Page 4-01

CHAPTER FOUR

WELDING OF STRUCTURAL STEEL

A 01 GENERAL REQUIREMENTS

401.100 Welding of structural steel shall conform to the requirements

of the AISC Specification and AWS D1.0, except where the AISC

Specification of AWS D1.0 is specifically modified or supplemented

by information included in the Drawings or Specifications.

402 QUALIFICATION AND CERTIFICATION OF WELDERS

402.100 Welders and welding operators (except resistance welding

machine operators) shall have passed the applicable AWS

qualification tests prescribed in AWS D1.0, Appendix D,

Parts II and III. AWS qualification tests shall be supervised and witnessed by an agency approved by the Engineer.

The approved agency shall issue certified test reports which

describe the tests performed and indicate the results of the

tests. Certification papers issued by the approved agency

shall clearly state the types of work the certified welder

or welding operator is qualified to perform. Certification

is to be achieved in the 12 months preceding the date the

subject welder begins work under the Contract. AWS qualification tests and certification shall be paid for by the

Authority and witnessed by the Engineer's designated

representat ive

.

'03 WELDING PROCEDURE SPECIFICATIONS AND JOINT QUALIFICATIONS

403.100 Joints conforming to the details specified in AWS Dl.0, Articles

209, 210, 211, 212, 213 and 214 and welded in accordance with the

NISTNCSTAR 1-1

A

WTC Investigation 283
Appendix E

Page 4-02

requirements of Sections 3 and 4 of AWS D1.0 are designated

prequalified with the following exceptions:

403.101 Partial penetration butt welds

403-102 Welds in steels with yield points exceeding 50 ksi.

403.200 The Contractor shall develop welding procedure specifications

for all welded joints. No joint shall be welded until the welding

procedure specification for that joint has been approved by the

Engineer.

403.300 For steels with specified yield points exceeding 50 ksi, welding

procedure specifications shall be qualified in accordance with

Article 502, AWS D1.0. No work containing a joint requiring

qualification shall be fabricated before welding procedure

specifications for that joint are qualified by the Contractor

and approved by the Engineer. Records of procedure tests shall

be maintained by the Contractor. Test reports shall be certified

by the Contractor and submitted to the Engineer for examination.

)04 PREHEAT AND INTERPASS TEMPERATURES

404.100 Preheat and interpass temperatures shall be those specified in

the welding procedure specifications prepared by the Contractor

and approved by the Engineer.

•05 '..*ELDING ELECTRODES AND FLUX

405.100 Manual welding electrodes shall be those scheduled in the Drawings

and shall in all cases be those specified in the approved welding

procedure specifications.

284 NISTNCSTAR 1-1A, WTC Investigation
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THE WORLD TRADE CENTER Page 4-03

405.200 'Welding electrodes and flux for submerged arc welding shall

conform to Section 202, MATERIALS.

405.300 Gas metal-arc welding materials, where approved for use in the

work, shall conform to Section 202, MATERIALS, and to the

requirements of the approved welding procedure specification.

405.400 Electronically controlled resistance welding of truss

panel points shall be approved provided the submitted

quality control provisions for weld strength and consistency are satisfied.

Resistance welds shall consist of four point scale free

welds developed by pressure contact of beaded chord angles

and round web sections. Where fillers and single web intersections occur, two point welds shall be developed by

pressure contact.

Welding cycle, welding pressure and current applications

shall be electronically controlled to assure uniform scale

free resistance welds in all cases to develop the strength

required in single or double shear.

Certification as to the weld strength as required by the

submitted quality control program shall be made available

to the Engineer.

NISTNCSTAR 1-1A, WTC Investigation 285
Appendix E

THE WORLD TRADE CENTER Page 3-01

CHAPTER THREE

FABRICATION OF STRUCTURAL STEEL

GENERAL

301.100 Structural steel shall be fabricated complete as shown in the

Drawings and in approved details shown in the shop drawings.

301.200 The steel furnished for each location shall have a minimum

yield point equal to that scheduled in the Drawings, and shall

be selected from the applicable steel specifications listed in

Chapter Two, MATERIALS.

301.300 All steel shall be ASTM A36 for locations where a specific

strength requirement is not stated in the Drawings.

IDENTIFICATION

302.100 The Contractor shall identify all steel which will be used in

the work beginning at the mill and shall maintain identification

at all times thereafter including during fabrication. The method

used shall sake both the grade and yield point of the steel

readily identifiable.

302.200 The Contractor shall identify each member or assembly with a system

of marks. Each mark shall be clearly indicated in the shop drawings.

The system of identification marks for fabricated structural steel

shall be approved by the Fngin^er

286 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Page 3-02 THE WORLD TRADE CENTER

03 SPECIFIC REQUIREMENTS

303.100 Flame cutting by hand shall not be performed without the

Engineer's approval. H.andcut surfaces shall be made smooth

by-chipping, planing or grinding.

303.200 Fabricated material containing sharp kinks or bends shall be

rejected. Material straightened prior to fabrication shall

be carefully examined for signs of distress or other defects

before being placed in fabrication. Distressed or otherwise

defective material shall not be used in the work.

303.300 Where required by the Contract Documents, surfaces shall be

milled, or finished by other approved means. All finishing

shall be clearly shown in the shop drawings.

303.400 Bolt holes and similar holes shall be punched, drilled, subpunched or sub-drilled and reamed, and shall not be made or

enlarged by gas cutting.

303.500 Holes req-uired by the Erector, and shown on the Drawings prior

to approval of Shop Drawings shall be furnished without cost.

NISTNCSTAR 1-1A, WTC Investigation 287
Appendix E

Page 3-02A

303.600 The Contractor may substite tees cut from rolled shapes in lieu of tees built up from plates at the beam and girder

seat connections in the drawings. Tees cut from rolled shapes shall be of a thickness and grade equal to or greater

than the thickness and grade of plates presently shown in

the drawings.

303.700 Where box beams in this Contract connect to columns by means

of a beam seat and top flange connection plate, the top

flange connection plate may at the Contractor's option be shipped loose with the box beam. No shims for "loose" top

flange connection plates are required.

303.800 The Contractor may elect to shop splice box core columns at each floor, at a point 3' -0" above the floor line. The edge

preparation and welding at these shop splices shall conform

to the edge preparation and welding shown for field splices

at box core columns in Drawing Book #3. Each individual sec- tion shall be milled, welded up, and then the completed column

shaft shall be milled to final length.

303.900 The Contractor may substitute a type 300 column, using plates

of the same grade, equivalent area and section modulus, for the type 400 box columns with a middle web. In this case, the Contractor shall provide any transitional section required to suit the type 400 or type 500 columns below the 9th story splice.

All fillet welds shall be in accordance with Drawing Book #3.

288 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

THE WORLD TRADE CENTER Page 3-03

304 FABRICATION TOLERANCES

304.100 Fabrication tolerances shall conform to the requirements

of the AISC Specification and AWS D1.0, as supplemented by

specific requirements contained in the Drawings and Specifications. In no case shall tolerances exceed those

obtainable by the best modem shop practice.

305 SPECIAL REQUIREMENTS

305.100 Fabrication tolerances shall conform to the tolerances shown

on Sheets 3-04 through 3-05 inclusive. Where specific

tolerances are not shown on Sheets 3-04 through 3-05 tolerances shall conform to the requirements of the Specifications.

305.200 Cut edges of steel shall be free of burrs, overhangs, gross laminations, excessive slag inclusions and similar defects.

Where necessary, cut edges shall be repaired by means de- scribed in the Contractor's quality control and testing

program. Where required to maintain weld quality, corners

of plates shall be eased and cut edges shall be ground.

Work of this nature shall be outlined in the Contractor's

quality control and testing program and shall be described

in detail in the Contractor's welding procedure specifications.

305.201 Repairs at gas cut edges made as follows will be approved"

by the Engineer:

Where serrations are not deeper than 1/8", edge

shall be hit with a grinder and sharp edges removed.

Where serrations exceed 1/8", the serrations shall be filled in with weld metal uniform in appearance; however,

grinding will not be required except in areas where beams

frame to column faces.

305.300 In certain locations in the Drawings, slotted or oversize

holes are specifically required. Where the Contractor elects

to use slotted or oversize holes not shown in the Drawings,

the use of slotted or oversize holes shall be subject to the Engineer's approval.

305.400 The Engineer will provide for the Contractor's use a table

of correction factors which the Contractor shall use to determine the correct as-fabricated dimensions of structural

steel members. The correction factor for columns will be

the sum of the correction for temperature at time of fabrication and the correction due to shortening under load. Correction factors will be based on a standard temperature

of 70 degrees Fahrenheit. The minimum increment of correction

to be included in the table of correction factors will be

1/16", said tables to be mailed to the Contractor cm June 30, 1967.

NISTNCSTAR 1-1 A, WTC Investigation 289
Appendix E

rZ Thickness ro/aror.ce

CA.S. T./st A'O'J

1A&

It ££2 s Ih&orerical

thickness.

DETAILING DIMENSIONS

Page 3-05

>i

!

the,

±'8 of sp//CG

%\ ±.'3'/6*at other locations

Compression joints which depend upon contact bearing, when assembled in the

shop, shall bear evenly with respect to the cancroid of the contact area. At

least 75 per cent of the entire contact area shall be irs full bearing; and the

separation of any remaining portion shall not exceed 0.01 inch except adjacent

to toes of flanges where a localized separation not exceeding 0.025 inch is permissible.

DEPTH. WIDTH AND OUT-OP -SQ(JAR£

TOLERANCES

rco&E COLUMN T/PEAOO $SOO)

290 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

C^ S. T. /-/f /A -0 J

X\ x.

t! \\ /\ f

I 4. tt Q.. 1 \ \ N

// 4 £2 - theoretical ^

thickness.

DETAILING DIMENSIONS

Page 3-04

Compression joints which depend upon contact bearing, when assembled in the

shop, shall bear evenly with respect to the centroid of the contact area. At least 75 per cent of the entire contact area shall be in full bearing and the separation of any remaining portion shall not exceed C.01 inch except adjacent

to toes of flanges where a localized separation not exceeding 0.C25 inch is permissible.

DEPTH

}

WIDTH AND OUT-Op-SQUARE

TOLEfiANCCS

CCORZ COLUMN TYPE300)

NISTNCSTAR 1-1A, WTC Investigation 291
Appendix E

THE WORLD TRADE CENTER Page 4-01

CHAPTER FOUR

WELDING OF STRUCTURAL STEEL

401 GENERAL REQUIREMENTS

401.100 Welding of structural steel shall conform to the requirements

of the AISC Specification and AWS D1.0, except where the AISC

Specification cx iWS D1.0 is specifically modified or supplemented

by information included in the Drawings or Specifications.

402 QUALIFICATION AND CERTIFICATION OF WELDERS

402.100 Welders and welding operators shall have passed the applicable AWS qualification tests prescribed xn AWS D1.0, Appendix D, Parts II

and III. AWS qualification tests shall be supervised and witnessed

by an agency approved by the Engineer. The approved agency shall

issue certified test reports which describe the tests performed and

indicate, the results of the tests. Certification papers issued by

the approved agency shall clearly state the types of work the certified

welder or welding operator is qualified to perform. Certification

shall have been achieved immediately preceding the date the subject

welder begins work under the Contract. AWS qualification tests and

certification shall be paid for by the Authority and witnessed by

the Engineer's authorized representative.

403 WELDING PROCEDURE SPECIFICATIONS AND JOINT QUALIFICATIONS

403.100 Joints conforming to the details specified in AWS D1.0, Articles

209, 210, 211, 212, 213 and 214 and welded in accordance with the

292 NISTNCSTAR 1-1A, WTC Investigation
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THE WORLD TRADE CENTER Page 4-02

requirements of Sections 3 and 4 of AWS D1.0 are designated

as prequalified.

403.200 The Contractor shall develop welding procedure specifications

for all types of welds such as: manual, semi-automatic and

automatic procedures for fillet, butt and groove welds.

No welding shall be done until the welding procedure

specification for that type of weld has been approved by

the Engineer.

404 PREHEAT AND INTERPASS TEMPERATURES

404.100 Preheat and interpass temperatures shall be those specified

in the welding procedure specifications prepared by the

Contractor and approved by the Engineer.

405 WELDING ELECTRODES AND FLUX

405.100 Manual welding electrodes shall be those scheduled in the

Drawings and shall in all cases be those specified in the

approved welding procedure specifications.

405.200 Welding electrodes and flux for submerged arc welding shall

conform to Section 202, MATERIALS.

405.300 Gas metal-arc welding materials, where approved for use

in the work, shall conform to Section 202, MATERIALS,

and to the requirements of the approved welding procedure

specification.

NISTNCSTAR 1-1 A, WTC Investigation 293
Appendix E

Page 1-17

THE WORLD TRADE CENTER

105 INSPECTION, QUALITY CONTROL AND TESTS

105.100 Quality Control and Tests (see Contractor's letter of 6/2/67

attached hereto;

105.101 The Contractor shall comply with the quality control

and testing program annexed hereto and forming a part

hereof during the course of the wort, to assure that

all work conforms to the Contract Documents,

105.102 Materials Control

All steel plates and shapes are subject to visual

inspection on receipt into the material receiving yard.

Unsatisfactory material is identified at this

point and referred to the Engineering Department for

disposition.

Copies of mill test reports are received by the

Quality Control Department. Heat numbers on all steel

items are identified and compared to mill test reports

to verify use of proper material.

Heat numbers are transferred to each main component by paint stick prior to cutting.

105.103 Material Preparation

All cutting, burning, punching, drilling operations,

etc., are subject to continuous visual inspection by

the Contractor.

105.104 Welding

Welders are to be qualified in accordance with

Appendix "D" of American Welding Society Codes Dl.0-66

and D2.0-66.

294 NISTNCSTAR 1-1A, WTC Investigation
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THE WORLD TRADE CENTER Page 1-18

If Authority requires welders to be re-certified,

Authority vill pay the cost of re-certification.

Each welding operator is assigned a steel stencil

identification symbol. Each welding operator shall

stamp for identification purposes each weld as it is

completed.

Preheat temperatures shall be checked by appropriate "tempsticks" prior to performing welds.

105.105 Testing by Contractor

Non-destructive testing of welds shall be accomplished

by either magnetic particle and/or dye penetrant methods.

The method selected shall be at the discretion of the

quality control supervisor of the Contractor.

Time of such testing and selection of welds to be

tested shall be the responsibility of the quality control

supervisor. However, these functions will be carried

out in a manner so as to provide a minimum of delays to

the production operation.

Non-destructive testing shall be performed on 100%

of the members during initial operations and then adjusted

so as to provide a maximum of 10% coverage of all shop

welds. The Contractor shall furnish all testing machines

,

testing machine operators and testing materials required

for the Contractor's quality control and testing program.

105.106 Welding Inspection

All preheat and welding operations shall be performed

under the continuous visual supervision of welding

supervisors and quality control inspectors.

NISTNCSTAR 1-1A, WTC Investigation 295
Appendix E

THE WORLD TRADE CENTER Page 1-19

105.107 Built-up Members

On completion of fit-up and prior to welding, inspect

for material size, thickness and dimensional conformance

with applicable shop drawings and tolerances in accordance

with the specifications.

Inspect for layout of mill line for shop splice.

Inspect welding of built-up members per 105.106.

Perform non-destructive testing per 105.105.

Perform final inspection of built-up members for

full compliance with Contract documents. Final acceptance

to be signified on record shop drawing for each member

inspected.

105.108 Building Components (Columns and Beams)

On completion of fitting of detail material to

built-up members (105.107, inspect detail for material

size, thickness, hole size, gauge, spacing, location

and dimensional conformance with applicable shop

drawings and tolerances in accordance with the specifications.

Inspect welding of detail material per 105.106.

Perform non-destructive testing per 105.105.

Inspect fit-up of shop splice (when applicable)

for multi-piece members.

Inspect welding of shop splice per 105.106.

Perform non-destructive testing per 105.105.

Inspect layout of final mill lines per applicable

shop drawings.

Perform final inspection of each building component

for full compliance with Contract documents.

296 NIST NCSTAR 1-1A, WTC Investigation
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Final acceptance to be signified on record shop

drawing for each member inspected.

105.109 The Contractor shall submit mill test reports to

the Engineer for all material used in the work.

The Contractor shall report the location and quality

of all corrective work.

The Authority's inspection will be provided at no cost to the 105.200 Contractor and is intended to assure conformance of Contractor's

fabricating operations and procedures with Contract documents.

The Authority to also provide mill inspection of materials to assur complete compliance with A.S.T.M. specifications as well as special

requirements of Stanray Pacific Corporation regarding quality and tolerance

.

105.201 Shop Inspection

The Authority will provide continuous visual

inspection of all operations.

Inspection is to be progressive and concurrent

with Contractor's quality control operation.

Non-destructive testing as performed by Contractor

(see 105.105) will be observed and witnessed by Port

Authority inspectors.

105.202 Final Inspection and Acceptance^Built-up Members}

On completion of fabrication, the Authority will perform

final inspection of each built-up member for full compliance with Contract documents. Inspect for material

size, thickness, weld size and workmanship. Final

acceptance to be signified on record shop drawing

each member inspected.

NISTNCSTAR 1-1A, WTC Investigation 297
Appendix E

THE WORLD TRADE CENTER Page 1-21

Building Components (Columns and Beams)

On completion of fabrication and prior to shipping, the

Authority will perform final inspection of each building

component for full compliance with Contract documents.

Inspect shop splicing (when applicable); fit-up of clips,

lugs, brackets, etc.; material sizes and thicknesses;

hole size, gauge and spacing; location, dimensional

conformance, welding and workmanship. Final acceptance

to be signified on record shop drawing for each building

component inspected.

106 DEFECTIVE WORK

106.100 Defective and unsuitable work end clX veiling to

conform to the Contract documents shall, where permitted

by the Engineer, be made good at the Contractor's expense.

Work may be rejected, regardless of previous approval in

shop drawings, inspection or inclusion in a certificate

of payment, provided that after final inspection and

acceptance by the Authority as provided in 105.202,

the Contractor shall have no responsibility or liability

for any defect whatsoever, except latent defects which a

reasonably prudent inspection would not disclose and any

errors in the shop drawings furnished by Contractor,

298 NISTNCSTAR 1-1A, WTC Investigation
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STAN RAY PACIFIC CORPORATION

subsidiary of STANRAY CORPORATION

11633 SOUTH . A « I 0 A STRICT <2 I 3 5 « 6 - < 11

1

June 2, 1967

Mr. Lester Feld

The Port of New York Authority

111 Eighth Avenue at Fifteenth Street New York, New York

THE TORT Of Him VOW AUTHORITY RECEIVED

JS67

WORID TRACK OtPARTKEnf WORLD TRADE CENTER

Subject

:

World Trade Center

Contract No. WTC 217.00 Revised Quality Control Program

Dear Lester:

Enclosed you will find two copies of the Welding Procedures to be incorporated into our Quality Control Program which is outlined in section 105 of Contract No. WTC 217.00. This constitutes our entire

Quality Control and Testing Program.

The Inspection Requirements referred to as item 2 C in your letter

of May 25, is now completed and will be mailed to you on Monday, June 5.

Yours very truly,

STANRAY PACIFIC CORPORATION

F. E. Allen

Control ler

dh

Encl.

NISTNCSTAR 1-1A, WTC Investigation 299
Appendix E

June 2, 1967

STANRAY PACIFIC CORPORATION

WELDING PROCEDURES

Manual Fillet Welds - Low Hydrogen Electrodes

Weld Type: MF-1

Material:

Electrodes:

Weld Position:

Electrode Size: Amperage:

Voltage:

Preheat:

Current

:

A36 E7018

IF; 2F, 3F 3/16" and 7/32"

3/16" - 200 to 275 7/32" - 260 to 340 3/16" - 21 to 25 7/32" - 22 to 26 To 3/4" T - Nominal Temperature Over 3/4" T - 100° F per inch thickness

to 250° F Maximum

D.C. reverse polarity, or A.C.

Weld Type: MF-2

Material

:

Electrodes:

Weld Position:

Electrode Size: Amperage:

Voltage:

Preheat:

Current

:

A36 E7028

IF and 2F 3/16" and 1/4"

3/16" - 225 to 310

1/4" - 325 to 430

3/16" - 23 to 27

1/4" - 24 to 29

To 3/4" T - Nominal Temperature

Over 3/4" T - 100° F per inch thickness

to 250° F Maximum

D.C. reverse polarity or A.C.

Manual Fillet Welds - Iron Powder Electrodes

Weld Type: MF-3

Material

:

Electrodes: Weld Position:

Electrode Size: Amperage:

Voltage:

Preheat

:

A36 E7024

IF and 2F

3/16" and 1/4"

3/16" - 230 to 310

1/4" - 325 to 430

3/16" - 23 to 28

1/4" - 24 to 30

To 3/4" T - Nominal Temperature

Over 3/4" T - 100° F per inch thickness

to 250" F Maximum

Current

:

A.C. or D.C.

300 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

WELDING PROCEDURES

Page - 2

-

Fillet Welds - Semi Automatic Innershield Wire

Weld Type: IS-1

Material

:

Electrodes: Weld Position:

Electrode „ize:

Amperage:

Voltage:

Preheat

:

Current

:

A36

NS-3M Flux Core

IF and 2F 0.120"

425 to 550

28 to 36

To 3/4" T - Nominal Temperature Over 3/4" T - 100° F per inch thickness

to 250° F maximum

D.C. reverse polarity

Fillet Welds - Tandem Wire Submerged Arc

Weld Type: SAMaterial:

Electrodes & Flux: Weld Position:

Electrode Size: Amperage:

Voltage:

Preheat

:

Current

:

A36 A.S.T.M

Flat

7/32

7/32" - 3/16" - 7/32" - 3/16" - To 3/4"

A558

and 3/16"

- 750 to

- 700 to

- 35 to

- 35 to T

950 85040

40

Norminal Temperature Over 3/4" T - 100° F per inch thickness

to 250° F maximum

7/32" - D.C. straight polarity

3/16" - A.C.

'illet Welds - Triple Wire Submerged Arc

Weld Type: SA-2

Material:

Electrodes & Flux: Weld Position:

Electrode Size: Amperage:

Voltage:

Preheat

:

Current

:

A- 36 A.S.T.M.

Flat

3/16"

3/16"

3/16"

5/32"

3/16"

3/16" No. 5/32" No. To 3/4" T

Over 3/4"

- A558

3/16' Lead

No. 2 No. 3 Lead

2

and 5/32"

Wire

,

Wire

Wire

,

Wire,

Wire,

Wire.

1000

850

750

353840

1200

1000 90040

to 43

to 46 Nominal Temperature

- 100° F per inch thicknesi

Lead Wire:

No. 2 Wire:

No. 3 Wire:

to 250° F maximum

D.C. straight polarity

A.C. A.C.

NISTNCSTAR 1-1 A, WTC Investigation 301
Appendix E

WELDING PROCEDURES

Page - 3

-

Complete Penetration Welds, Manual Electrodes

Partial Penetration Welds. Manual Electrodes

Weld Type: MB-1

Joint Specification: A.W.S. D1.0, Appendix E2 and £4

Material:

Electrodes:

Weld Position:

Electrode Size: Amperage:

Voltage*.

Preheat

:

Current

:

A3 6 E7018

1G; 2G; 3G

5/32" and 3/16"

5/32" - 150 to 200 3/16" - 180 to 260 5/32" - 20 to 26 3/16" - 22 to 27 To 3/4" T - Nominal Temperature

Over 3/4" T - 100° F per inch thicknesa

to 250° F Maximum

D.C. reverse polarity or A.C.

Complete Penetration Welds, Semi Automatic Innershield

Partial Penetration Welds. Semi Automatic Innershield

Weld Type: IS-2

Joint Specification: A.W.S. D1.0, Appendix E2 and B4

Material:

Electrodes

:

Weld Position:

Electrode Size:

Amperage:

Voltage:

Preheat:

Current:

A36 NS-3M

1G and 2G 0.120"

425 to 500

26 to 30 To 3/4" T - 70° F Over 3/4" T - 100° F per inch thicknese

to 250° F maximum

D.C. reverse polarity

302 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

WELDING PROCEDURES

Page - 4 -

Complete Penetration Welds, Manual and Semi Automatic

Partial Penetration Welds. Manual and Semi Automatic

Weld Type: CB1

Joint Specification: A.W.S. D1.0, Appendix E2 and E4

Material: A36 Electrodes: Manual - E7018 root passes

Semi Automatic - NS3M Innershield

Weld Position: 1G and 2G Electrode Size: E7018 - 5/32"

NS3M - 0.120" Amperage: 5/32" E7018 - 150 to 220 NS3M - A 75 to 500 Voltage: E7018 - 22 to 25 NS3M - 28 to 32 Preheat: To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness

to 250° F maximum

Current: D.C. reverse polarity

Manual Fillet Welds - Low Hydrogen Electrodes

Weld Type: MF-S1

Material

:

Electrodes:

Weld Position

Electrode Size: Amperage:

Voltage:

Current:

Preheat:

A572, Grade 50 E7018

IF, 2F, 3F 5/32" and 3/16"

5/32" - 150 to 200 3/16" - 200 to 250 5/32" - 20 to 24 3/16" - 21 to 25 D.C. reverse polarity or A.C. To 3/4" T - 70° F Over 3/4" T - 100O F per inch thickness

to 250° F to 300° F maximum interpass temperat

Temperature Control: "Templl-Stik" Crayons or equal

NISTNCSTAR 1-1A, WTC Investigation 303
Appendix E

WELDING PROCEDURES

Page - 5

-

Weld Type: MF-S2

Material

Electrode

Weld Posi

Electrode

Amperage:

Voltage:

Current: Preheat

:

Temperatu

A572, Grade 50

s: E7028

tion: IF and 2F

Size: 3/16" and 7/32"

3/16" - 220 to 300 7/32" - 250 to 350 3/16" - 23 to 27 7/32" - 23 to 28 D.C. reverse polarity or A.C.

To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness to 250° F

maximum. 300° F maximum interpass temper at' re Control: "Tempil-Stik" Crayons or equal

Semi Automatic Fillet Welds - Inncrshield Electrodes

Weld Type: IF-Sl

Material: A572, Grade 50 Electrodes: NS3M Flux Core Weld Position: IF and 2F

Electrode Size: 0.120"

Amperage: 425 to 500 Voltage: 28 to 36 Preheat: To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness to 250° p maximum. 300° F maximum lnterpaas temperatu

Temperature Control: "Tempil-Stik" Crayons or equal

Submerged Arc Fillet Welds - Dual Tandem Wire

Weld Type: SA-S1

Material:

Electrodes & Flux: Weld Position:

Electrode Size:

Amperage:

Grade 50

,M. - A558

and 3/16"

A572, A.S.T

Flat

7/32"

7/32" - 850 to 950

3/16" - 800 to 900 Voltage: 7/32" - 35 to 40

3/16" - 35 to 40

Current: 7/32" - D.C. straight polarity

3/16" A.C. Travel Speed: 30 to 36 inches per minute

Preheat: To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness to 250© F maximum. 300° F maximum interpass temperat'

Temperature Control: "Tempil-Stik" Crayons or equal

304 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

WELDING PROCEDURES

Page - 6

-

Submerged Arc Fillet Welds - Triple Tandem Wire

Weld Type: SA-2S

Material: A-S72, Grade 50 Electrodes & Flux: A.S.T.M. - A558 Weld Position: Flat Electrode Size: 3/16", 3/16" and 5/32"

Amperage: 3/16" lead wire - 1100 to 1200 3/16" No. 2 wire - 900 to 1000 5/32" No. 3 wire - 850 to 900 Voltage: 3/16" lead wire - AO

3/16" No. 2 wire - A3

5/32" No. 3 wire - 46

Current: Lead wire - D.C. straight polarity

No. 2 wire - A.C.

No. 3 wire - A.C. Travel Speed: 45" per minute

Preheat: To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness to 250°

F

maximum. 300° F maximum interpase temperature

Temperature Control: "Tempil-Stik" Crayons or equal

Complete Penetration Welds

Partial Penetration Welds - Manual, Low Hydrogen Electrodes

Manual. Low Hydrogen Electrodes

Weld Type: MB-S1

Material

:

Electrodes:

Weld Position:

Electrode Size: Amperage:

Voltage:

Current: Preheat

:

A572, Grade 50 E7018

1G, 2G, 3G

5/32" and 3/16"

5/32" - 150 to 200 3/16" - 175 to 260 5/32" - 20 to 26 3/16" - 22 to 27 D.C. reverse polarity, or A.C. To 3/4" T - 70° F Over 3/4" T - 100° F per inch thickness to 250° F maximum. 300° F maximum interpass temperature

Temperature Control: "Tempil-Stik" Crayons or equal

NISTNCSTAR 1-1A, WTC Investigation 305
Appendix E

WELDING PROCEDURES

Page - 7

-

Complete Penetration Welds - Semi Automatic Innershield

Partial Penetration Welds - Semi Automatic Innershield

Weld Type: IE-S2

Material: A572, Grade 50 Electrodes: NS3M Flux Core Weld Position: 1G and 2G Electrode Size: 0.120"

Amperage: -425 to 500 Voltage: 30 to 34 Current: D.C. reverse polarity

Preheat: To 3/4" T - 70° P Over 3/4" T - 100° F per inch thickness to 250° * maximum. 300° F maximum interpass temperature

Temperature Control: "Tempil-Stik" Crayons or equal

Complete Penetration Welds - Manual Electrode and Semi Automatic

Partial Penetration Welds - Manual Electrode and Semi Automatic

Weld Tvoe: CB-S2

Material

:

Electrodes:

Weld Position:

Electrode Size:

Amperage:

Voltage:

Current

:

Preheat

A572, Grade 50 Manual - E7018

Semi Automatic - NS3M Flux Core

1G and 2G £7018 - 5/32"

SS3M - 0.120"

5/32" E7018 - 150 to 220 NS3M - 450 to 500

5/32" E7018 - 22 to 26 HS3M - 28 to 32 D.C. reverse polarity

To 3/4" T - 70° F Over 3/4" T 100c maximum.

F per

300° Temperature Control: "Tempil-Stik" Crayons ot equal

inch thickness to 250<> F

F maximum interpaae temperature

306 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

WELDING PROCEDURES

PAGE- 8-

CRITERIA FOR ADJUSTING PERCENTAGE OF NON-DESTRUCTIVE TESTING

Non-destructive testing of welds will be performed using either

the dye penetrant and/or the magnetic particle process. Welds will be

checked for performance with applicable ASTM specification. Non-destructive

testing of welds will be performed on 107„ of all members.

1007. of the linear footage of each weld will be checked on the

first 10 columns and on the first 10 beams fabricated. Provided that all

welds checked are found to be acceptable, then 100% of the linear footage

of each weld on 5 columns and on 5 beams out of the next 10 fabricated will

be checked. Providing at this point that all welds checked have been found

to be satisfactory, then 101 of the linear footage of each weld on one

member out of each 4 fabricated will be inspected for the balance of the

contract.

Each unacceptable weld will be examined, using the previously

described non-destructive methods, for its complete length. For each weld

found to be unsatisfactory an additional like weld will be examined on an

additional member.

NISTNCSTAR 1-1 A, WTC Investigation 307
The Port of New York Authority

111 Eighth Avenue New York, New York 10011

The World Trade Center

FABRICATED STEEL

Contract WTC-217.OO

June 6, 1967

ADDENDUM #D2

This addendum should be physically annexed to the Form of Proposal, but the Form of Proposal will in any case be construed as though this addendum had been so physically annexed and all addenda

issued will be considered incorporated in the Form of Proposal.

In Drawing Book #3, Page 56, dated 9/12/66, revise the last

two items in the table to read as follows:

t * Weld #2

2-7/8" through 3-7/8" 1/2" **

4" through 8" 5/8" **

* For Weld #2, t is the thickness of the thicker plat , connected by the weld.

** Indicates "deep penetration" fillet welds using Stanr. ; Pacific Corporation procedures as documented in letter

of May 23, 1967 from H. F. Kjerulf to L. S. Feld are

acceptable.

4*, <?^%7^-

/7 Guy F. TozzoliK

Director

J World Trade Department

NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKILLIN6-HELLE-CHRISTIANSEN-ROBE RTS O N

Consulting Structural and Civil Engineers • 230 Park Avenue, New York, N. Y. 10017 • Mu. 9-SS7-J

/oftn B. SfciZiing Hclgc J. Helle • John. V. Christiansen • Lcih'c £. Robertson

Coruu/tonli June 5, 196? II«oW L. Wlorthingten

/ojrph F. JdcUnn

Mr. JUilcoln ?. Levy

Pore of New York Authority

World Trade Center Planning

121 Eighth Avenue

New York, New York 10011

Rcfcrcr.cc : The World Trade Center

Contract WTC-217.00, Stanray Pacific

Inspection, Testing, Coordination and

Supervision at Fabricating Plant

Centlercen:

Contract WTC-217.C0 contains provisions stipulating that irrevocable title

to "built-up nenbers" and to "building components" passes to PNYA after the

completion of dctuilod inspection and acceptance by PNYA. Tnc contract also

states that PNYA assumes all risk for loso or damage of fabricated ur.ita after they are placed in the honde of the shipper. These contract provisions,

coupled vith the major uso of etocl produced in Japan and England, cake It

necessary for PNYA to implement a comprehensive program of supervision,

coordination, inspection and testing of the work performed by Stanray Pacific

Corporation. The coordination function assumes particular icportar.ee because

of the large quantities of steel to be supplied fron abroad. Stanray Pacific

cuat receive delivery of this steel in tine to meet the approved progress

schedule vhich, in turn, forms an integral part of the overall progress

schedule for. Tnc World Trade Center.

Accompanying this letter is a conprchencivc program for cuue-rvision, o>o reinat ion,

inspection and testing based on the use of the personnel and facilities of a loci independent testing agency supervised by a Resident Engineer. Vie propose

that PNYA implement the program outlined horein under the oupervision of professional engineers in the employ of SHCR.

mrp.1 A. Iltwla

r i < a. rocTcn

r«AM« no«Lirt»».o" >M»T t. LtVI«»

V. A. l*BI»AO»KV xm « . ttoiti

CHUUI »AMOU»«»

WILLIAM D . WAKO

(. 4 . XMITC. J « . LOMKtt i~ WIOIHO

• « A T T L « O » r . C I , I • « • WAtHlnOTDK t U I L D I » « , It'ltVIl »»A»«tHOT©>.

NISTNCSTAR 1-1A, WTC Investigation 309
Appendix E

SKtLLINQ - HELLE-CHRI ST IANSEN - ROBERTSO N

- 2 _

The Fvcsidcnt Engineer will be in a position to work closely vith the mill,

the dctailer, the fabricator and tho chipper. Kis responsibility will be

liaitcd to that of reviewing end reporting on the vork and to directing the

activities of the testing and inspection, agency. Ho will establish full-cino

residence at tho fabricating plant, beginning approximately 5 weeks prior to

tfcc beginning of fabrication and will remain in residence until such tiac as

and SHCR ectermino that weekly visits crc sufficient. .

The program proposed herein will provide PXYA with all tho nccoosary documentation

required to assure that the work con fores to the Contract Docuacatc, and at the same tima, will give, PNYA early aotico of potential delays in tho work, thereby

providirv; ?KYA oaxisua opportunity to preclude these delays.

For convenience, ve have attached Xerox copies ofprovious corrcspondeaceV

concerning Contract VTC-217.00.

Very truly yours,

SKIUING-EELUI-CiRISTlAKSEN-fcOSERTSOH

Icslic E. Eobcrtson.

L£K;e

cc: Mr. A. Sclvrcier, MSA

Mr. J. Soiamoa, KRS

Mr. 1. teld, PXYA

Mr. J. Euciar, Tichman

Mr. V. CoRinuk*

V,

3. fn- »

1 '

310 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

COORDINATION,, SUPERVISION, INSPECTION* AND TESTING

OF FABRICATED STRUCTURAL STESl

Stanray Pacific, Contract WTC-217.00

A. Scope

1. Supervision, coordination, inspection end testing activities must be

performed during the course of the vork in order to ensure proper

interpretation of the technical provisions of the contract, to provide

PNYA assurance through adequate documentation that fabricated 6teel

confonas to the Contract Documents, and to assure on-time delivery of

fabricated steel to PNYA by identifying potential sources of delay at the earliest possible moment.

2. Detailed Inspection by check list and by non-destructive testing oust be

performed prior to final acceptance of:

a) each "built-up member" and

b) each "building component"

to enable PNYA and SHCR to identify unacceptable fabricated items prior

to final acceptance, such acceptance being irrevocable under the terms of the contract.

B. Personnel

1. Supervision, coordination, inspection and testing activities shall be

managed by a Resident Engineer (a professional engineer employed full

time by SKCR)

.

2. Inspection and testing activities shall be performed by qualified and

experienced technicians in the full rime employ' of an independent: _r*s»"$t«;

agency retained and paid by PNYA. The testing agency 6hall submit to PNYA and SHCR detailed resumes of the qualifications and experience of

each man proposed for assignment to the work.

C. Records and Drawings

1. The fabricator shall provide the Resident Engineer with one copy of each

of the following:

a) Each advance bill for mill order

b) Each bill of 'lading for shipment of etcel plate

BKILLlNG-HELl.e-CHRlSTIAN BEN-ROBERTSON

NIST NCSTAR 1-1A, WTC Investigation 3 1

1
Appendix E

c) Each certified mill tC6t report

d) Each typical detail sheet

e) Each approved erection plan

f) Each approved steel detail drawing as corrected to reflect any and

all approval notations.

g) Each shop bill of material

h) Each fastener and welding material list

i) Each shipping bill or bill of lading or both for completely fabricatec

and accepted components

j) The fabricator's Quality Control Program for the vork.

k) Te6t documents certifying qualification in accordance with the

provisions of AW5 Dl.0-66 for each

<1) welder,

(2) welding machine" operator, and

(3) welding procedure specification applicable to the vork.

2. PNYA and SHCR will' provide the Resident Engineer with the following;

a) . A complete set of contract documents including all revisions to the

contract documents

b) One print of each approved or corrected shop drawing

c) One copy of the current approved" fabrication schedule

d) One copy of each mill Inspection report

3. The Resident Engineer will:

•a) , Prepare a daily report of hie activities, and will submit .these reports weekly, or more of ten where special conditions warrant

b) Maintain a complete up-to-date file of all welding certification

documents

c) Maintain a complete file of test and inspection reports prepared by

tnc m'cepenctut testing agency.

d) Maintain complete ana orderly files of all other data provided to the Resident Engineer by the fabricator, PKYA and SHCR.

A. The independent testing agency will prepare test- and inspection reports on a daily basis. Test reports shall record the results of each test or

related group of tests and shall clearly identify each member or component tested, type of test made, and results of each test. Individual

inspection reports shall be made for each inspector's work and f'**11 specifically note each member or component inspected, specific arcems included in the inspection, and results of the inspection

eKlLUINa-MEUUE-C«RI6TIANSEN-ROBERT80N

312 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

D . Supervision

1. Supervision shall be perfcreed by the Resident Engineer,

2, Supervision shall include:

o) A complete study of the fabricator's quality control procedures,

proposed fnbrication-jsrocedurcs, provisions for storage of incoming

components," and provisions for loading and shipping of corspletcd

"building components". This study will be made by the Resident

Engineer prior to the beginning of fabrication. The Resident

Engineer will submit a cooplctc report and analysis of his findings

to SKCR and PNYA prior to the beginning of fabrication.

b) Liaison between PNYA and SHCR on the one hand, and Dovell Engineering

Cocpany on the other, regarding the preparation and approval of 6hop

c) Ensure proper interpretation of the Drawings and Specifications by

assistance to the fabricator. Where the Resident Engineer determines

that a ruling from the Engineer is in order, he will expedite receipt

of the Engineer* 6 ruling by immediately reporting all pertinent data

to SHCR and PN"YA.

d) Direction of the work performed by the independent testing agency and

its inspectors. The scope of inspection and testing is defined in

the work which, in the Judgment of' the Resident Engineer, warrant

additional inspection or testE, the Resident Engineer ihall have the

authority to order such additional inspection or tests as he deem6

necessary. The Resident Engineer shall report to SHCR and PNYA

immediately all such instances,

s] CwuCiaudl Bu&vexliunce of tnc quality or the work including

(1) Checking material as received and stored in the receiving and

material, for completed "built-up members" and for "building

drawings.

Should conditions, occur during the course of

(2)

storage yard for

(a) Grade, heat number and marking

(b) Condition

fc) Dimensions

(d) Method of storage

Cro86-checking of certified mill test reports against material

received at the receiving and storage yard.. Item* (?) end (b)

8KILl.lN8-HELUE-CMRI8TIAN8EN«R08ERTflON

NISTNCSTAR 1-1A, WTC Investigation 313
Appendix E

shall be performed immediately upon receipt of material at the

receiving and storage yard.

(3) Random checking during fabrication of width, length and

thickness of plate, layout work, edge preporation, jigs and

templates, welding of sain members, preparation of detail

material, welding of detail material, distortion control, silling

of columns, and other items as required.

(4) Surveillance of the fabricator's quality control program as actvially implemented by the fabricator, including review of any

reports prepared by the fabricator for' submission to SHCR and PKYA.

<5) Continual direction of inspection and testing work performed to ensure adherence to the amounts of inspection and testing outlined

in Parts^and ^^hercin.

E. Coordination

1. Coordination shall be performed by the Resident Engineer with the assistance

of inspectors from the independent testing agency.

2. Coordination shall include

a) Continual scrutiny of the approved progress schedule.

b) Organization of advance bills of material into groups based on dates

material must be delivered to conform to progress schedule.

c) Review of bills of lading for shipment of material against advance

bill6 or material and approved progress schedule.

<D Check of material actually on hand in receiving and storage' yard

against a), b) , and c) above. The Resident Engineer shall notify

che fa. cacor, SHCR and PNYA immediately upon discovery of any discrc .icy or omission.

e) Check ; each unit from the beginning of fabrication until loaded

for pment. The date anu time shall be clearly recorded on the

Res nt Engineer's copy of the applicable shop drawing and erection

dr- ,ng for

(' beginning of fabrication

/ final acceptance of "buildup member"

(3) final acceptance of "building component"

(4) completion of loading for shipment.

The Resident Engineer shall notify the fabricator, SHCR and PNYA .aaeciately should any unit fall behind schedule, and shall notify

shilling — h 6 ule — Christiansen- Robertson

314 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SHCR and PKYA promptly of the date fabricated components actually

leave the fabricator's yaTd.

F. Inspection

1. Inspection shall be performed by qualified and experienced structural steel

inspectors in the full time employ of the independent testing agency.

2. Only inspector's approved by PNYA and SKCR shall be assigned to the work.

Approval will be based on review of detailed resume's of each inspector's

qualifications, experience and ability to perform the required work.

3. Generally, one full time inspector shall be asoigncd to each work shift.

The Resident Engineer shall have the authority to increase the number of

inspectors working in a given shift in accordance with amount of inspection

work to be performed, or to reduce or increase the hours worked by any

inspector as work load varies.

A. Duties of inspectors wili be as follows:

a) Assisting the Resident Engineer as required in analyzing and cross- checking advance bills of material, bills of lading for material and

•certified mill test reports

b) Checking each plate upon arrival at the receiving and storage yard for

(1) Heat number and specification conformance

(2) Condition

(a) Edge defects (laminations, slag inclusions)

(b) Surface defects

(c) Damage (bends, kinks)

c) Checking of "built-up members" during fabrication

(1) Plates

(a) Beat number and yield point.

(b) Length, width and thickness

ic) Tolerance conformance

(d) Edge and surface defects

(2) Jigs, templates and positioners

(a) Suitability

(b) Dimensional accuracy

(c) Alignment

(3) Welding

(a) Edge preparation

(b) . Fit-up (proper use of tack velds, diaohragm plates, Jigs)

SHILLING — HELLE — CHRISTIAN8EN — ROBERT 60N

NIST NCSTAR 1-1A, WTC Investigation 3 1

5
Appendix E

(c) Position for welding

(d) Flux, electrode, preheat, type of welding equipment, voltagw

. and amperage for conformance to welding procedure specification

<e> Visual check of 100Z of coaplcted welds

(f ) Select lengths of veld for non-destructive testing to b<» perfortaed after member cooIb

(A) Fully welded members shall be checked after cooling for conformance

to the required tolerances (camber, sweep, out-of-square)

;5) Finishing

(a) Theoretical centerline

(b) Killing of first end for perpendicularity to theoretical

centerline

c) Check layout of length for milling second end including

corrections to theoretical length for temperature and

shortening under load

(d) Check of perpendicularity to theoretical centerline of seconc

end

(eD Final check of actual length after milling is complete

d) Checking of "building components" during fabrication

(1) Heat number and yield point of detail material

(2) Proper size and weight of steel sections or thickness of plate

(3) Layout of. detail material for proper -"location of- holes, copes

and cuts

(4) Fit-up of detail material

(a) Proper fit-up for welding

(b) Proper location off theoretical column centerline'

(5) Visual check of 1002 of detail welding

(6) beiect lengths of detail welds for noh-destructive testing

e) Final check

(1) Check main material for dimensions

(a) Length

(b) Width

(c) Thickness

(2) Check" main material for conformance to steel spec. A36, etc.

316

SKILUINO-l-lEUl-E -CHRISTIAN SEN - RCf O E RT8 Of»

NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

(3) Check basic dimensions

(a) Overall length

(b) Sweep, camber, out-of-6quare

(c) Theoretical ccnterline

(d) Finished surfaces for 90* angle to ccnterline

(4> Check, detail material

(a) Length, width, thickness, copes

'b) Hole patterns, edge preparation, etc.

!c) Conformance to steel specifications

,'d) Location in relation to theoretical centerlinc

'e) Location longitudinally

(f) Freedom of edges from burr, lamination, slag inclusion, ccc.

(g) Cleaning of steel

(h) Protection of- milled surfaces

(i) Accurate and clear marking

">) Checking will be against structural drawings wherever possible.

Results of inspection will he recorded on the Resident Engineer.'

a

record set of shop drawings.

Testing

1. Testing activities will be performed by personnel in the full time employ

of the testing laboratory. Non-destructive testing will be performed by

persons fully qualified, experienced and canable in the non-destructive

testing technique used.

2. Testing activities fall into two categories:

a) Non-destructive testing performed at the material receiving and sto* yard and in the fabricating works

b) Testing performed at the testing laboratory

3. Non-destructive testing may be divided .into five categories

a) Visual inspection (including measurements)

b) Dye penetrant inspection

c) Magnetic particle inspection

c) Ultrasonic inspection

e) Radiographic' inspection

Visual inspection will ascertain the locations where other types o: testing will be employed.

EKILLINO-HCLLC

NISTNCSTAR 1-1A, WTC Investigation

—CHRISTIANSEN-ROBERTSON

317
Appendix E

5. Dye penetrant inspection will be used as a random spot check of velds where

such inspection is Judged desirable by cither the inspector or the Resident

Engineer.

6. Magnetic particle inspection will be used to inspect a minimum of 5 percent

of all member and detail welds.

7 Ultrasonic inspection will be used where the Resident Engineer determines

special conditions warrant this type of inspection.

8. Radiographic inspection will not be required for the subject work.

9. Testing performed at the testing laboratory falls into three categories;

a) Testing of specimens for welder and welding machine operator

qualification tests

b) Mechanical tests of steel plate or weld metal

c) Chemical (check) analysis of steel plate or weld metal

It is anticipated that only a) above will oe required. However, should

special conditions warrant, the Resident Engineer shall have the authority

to -call for tests listed under b) and c) in the number judged necessary by

the Resident Engineer.

318

S K 1 U U I N O •»* M E U k. e - C M R I 6 T i A N S E N

R0BERT60N

NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

DRAFT 8/25/67

United States Testing Company

1514 Park Aver.uc Hoboken, New Jersey

Gentlemen:

The undersigned, The Port of New York Authority, hereinafter

referred to as the "Authority", hereby offers to retain The United States

Testing Company,* hereinafter referred to as 'U. S. Testing" to furnish

to the Authority for such periods of cine 06 the Construction Manager

or Assietont Construction >{anager of the World Trade Center of the

Authority, hereinsfter called the 'Manager" may require, the services

of such number cf experienced and qualified steel inspectors and field

and laboratory technicians who arc qualified to perforin the services

listed In Appendix 1 attached hereto and forming a part hereof in

connection with such quantities of steel to be incorporated in the

World Trade Center being constructed by the Authority in the City of

New York ae may be fabricated by the Stanroy Pacific Corporation at

their facilities located in Los Angeles, California and at the direction

of the Manager to perform physical and chenical tests on foreign steel

samples which will be forwarded to the U. S. Testing Laboratories in

Koboken, New Jersey. U. S. Testing shall not, without its further

consent, eitner express or impixec, oe uullguieu wv i»rtu«'i »uwti

services after December 31, 1970.

The Authority will obtain entrance for U. S. Testing to

fabrication shops where U. S. Testing is required to perform its

services and will furnish to U. S. Testing necessary technical specifications, drawings, shipment dates, and other information required

for it to perform its services hereunder.

NISTNCSTAR 1-1A, WTC Investigation 319
Appendix E

APPENDIX NO. I

SCOPE OF DUTIES

F. Inspection

1. Inspection shall be performed by qualified and experienced structural

steel inspectors in the full time employ of the independent testing

agency.

2. Only inspectors approved by PNYA shall be assigned to the work.

Approval will be based on review of detailed resumes of each inspector's

qualifications, experience and ability to perform the required work.

3. Generally, one full tine inspector shall be assigned to each work

shift-. The Supervising Engineer to be supplied by the Authority shall

have the authority to increase the number of inspectors working in

a given shift in accordance with amount of inspection work to be

performed, or to reduce or increase the hours worked by any inspector

as work load varies.

4. Duties of inspectors vill be as follows:

a) Assisting the Supervising Engineer as required in analyzing and

cross-checking advance bills of material, bills of lading for

material and certified mill test reports

b) Checking each plate upon arrival at the receiving and storage yard

for

(1) Heat number and specification conformance

£) Condition

(a) Edge defects (laminations, slag inclusions)

(b) Surface defects

(c) Damage (bends, kinks*

c) Checking of "built-up oembers" during fabrication

(1) Plates

(a) Heat number and yield point

(b) Length, width and thickness

(c) Tolerance conformance

(Q) fclcge and surface defects

320 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

(2) Jigs, templates and positioners

(a) Suitability

(b) Dimensional accuracy

(c) Alignment

(3) Welding

(a) Edge preparation

(b) Fit -up (proper use of tack velds, diaphragm plates , jigs)

(c) Position for welding

(d) Flux, electrode, preheat, type of welding equipment,

voltage and amperage for conformance to welding pro*

cedure specification

(e) Visual check of 100% of completed welds

(f) Select lengths of weld for non-destructive testing to be performed after member cools

(C) Fully welded oeabcrs shall be checked after cooling for

conformance to the required tolerances (camber, sweep, outof -square)

(5) Finishing

(a) Theoretical centerline

(b) Milling of first end for perpendicularity to theoretical

centerline

(c) Check layout of length for milling second end including

corrections to theoretical length for temperature and

shortening under load

(d) Check of perpendicularity to theoretical centerline of

second end

(e) Final check of actual length after milling is complete

d) Checking of "building components" during fabrication

(1) Heat number and yield point of detail material

(2) Proper size and weight of steel sections or thickness of plate

(3) Layout of detail caterial for proper location of holes, copes

(A) Fit-up of detail material

NISTNCSTAR 1-1A, WTC Investigation 321
Appendix E

(5) Visual check of 100% or" detail welding

(6) Select lenghs of detail welds for non-destructive testing

e) Final check

(1) Check main material for dimensions

<a) Length

00 Width

(c) Thickness

(2) Check main material for conformance to steel spec. A36 , etc.

(3) Check basic dimensions

(a) Overall length

(b) Sweep, camber, out -of -space

(c) Theoretical center line

(c) Finishes surfaces for 90° angle to centerline

(4) Check detail material

(a) Length, width, thickner.s , copes

(b) Hole patterns, edge preparation, etc.

(c) Conformance to steel specifications

(d) Location in relation to theoretical centerline

(e) Location longitudinally

(f) Freedom of edges from burr, lamination, slau inclusion, etc.

(g) Cleaning of steel

(h) protection of milled surfaces

(i) Accurate and clear marking

(5) Checking will be against structural drawings wherever possible.

Results of inspection will be recorded on the Supervising Engineer's

record set of shop drawings.

322 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

f) Witness and certify qualification of Welders

g) Check Contractor's invoices for quantities of acceptable oaterial

G. Testing

1. Testing activities vill be perforaed by personnel in the full time employ

of the testing laboratory. Non-destructive testing will be pcrforoed

by persons fully qualified, experienced and capable in the nondestructive testing technique used.

2. Testing activities fall into two categories:

a) Non-destructive testing performed at the taaterial receiving and

storage yard and in the- fabricating works

b) Testing performed at the testing laboratory

3. Non-destructive testing cay be divided into five categories

a) Visual inspection (including ceasuresents)

b) Dye penetrant inspection

c) Magnetic particle inspection

d) Ultrasonic inspection

e) Radiographic inspection

A. Visual inspection will ascertain the locations where other types of

testing will be eaployed.

5. Dye penecrant inspection will be used as a rondos spot check of welds

where such inspection is judged desirable by either the inspector or

the Supervising Engineer.

6. Magnetic particle inspection will be used to inspect a minitauo of 5 per

cent of all nember and detail welds.

7. Ultrasonic inspection will be used where the Resident Engineer determines

special conditions warrant this type of inspection.

NISTNCSTAR 1-1A, WTC Investigation 323
Appendix E

S. Radiographic inspection will not be required for the subject work.

5. Testing performed at the" testing laboratory falls into three categories:

a) Testing of specimens for welder and welding machine operator

qualification tests

b) Mechanical tests of steel plate or weld metal

c) Chemical (check) analysis of steel plate or weld metal

It is anticipated that only a) above will be required. However,

r.nould special conditions warrant, the Supervising Engineer shall have

the authority to call for tests listed under b) and c) in the number

judged necessary by the Supervising Engineer.

324 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

S K I LL1 NS-HE LLE - CHRI STI AM SEN - ROBE RTS O N

Ccrj-J:ir.s Sux::uTsl and CivR Engineers • 230 Park Avenue, Xcii> York, N. Y. 10017 • Mu. 9- k7<i

Jofcr. 5. Si:'^ • Hcigs J. HcSc • JoAn. V. Ciirisiuraien LcsKc E. Robertson

Ccnnthaitii j^oxil 5, 1967 Hareid L. \X'cnk:r.;:cn foscph r . jtiction

Pert of Nev Vcrls Authority

"crld Trede Center Plenuing

111 Eighth Avcaua

Xcv York 11, Xcv York

Attent ion: Mr. Xolcols P. Levy

Reference: The World Trede Center

Mill Inspection of Jopsr.csc Steel

Ceutloncr:

Verification thot structure! steel produced is Jcpen confoms to the

Specifications for The World Trndc Center fells into four breed cetc^orics

cd follows:

1. testir-n end inspection performed by the sill,

2. war* vhich vill bo performed by SI-ICS.. 3. vorh vhich ney be perfomed by on independent testing

Isboretory under contrsct to PXYA , end

s. \rcr!c vhlca io the specific responsibility of the

febricetor.

First, follouins stenderd AST.: procedures, the nill is required to perfom

chor.ical end physical testing to eesure itself end document to the purcV.es er thet the requirement s of the cpplieeblc nr.tcriol specif icetion fesva been net. Heeh beet is analysed for cher.icel cc-posirior. by ledle analysis end

physical test.- arc aada in etc^rdAnca vith the recuirer.c-a.ts of the applicable

mnteriel specificetica. "or inster.ee, AST.-: ."302 requires tension and bend

testing of each plate as rolled, -..-bile A.CT.< A3 6 rcruircs tcn.-.ion and bend

testing of cech beet. The results of these tests era recorded on a sill test report beerinc a statement certifying the correctness of the deta reported

»'. - - a . rotrjw

liOu«..tT Z. LCVitii

V. A. miiili«V

KCKT » . HbClul

WUktAtl fe . WA ft tb c. j. wHirt. in

,

NISTNCSTAR 1-1A, WTC Investigation 325
Appendix E

SKILLIN6-HELLE-CHRI ST I A N SEN - ROBS RTS O N

2 -

under which the signature of the Chief Metallurgist or ether authorised

agent of the mill Appears. The correctness of tho sill test report nzy be

further or tested by the signature of a notary public. Tho purchaser cay

have finished notorial representing each heat checked for chemical composition

by check analysis. VThilc chic ic rarely done ir. cotmiercial building construcrior., it is occasionally required in bridge and governmental work. Check

analysis ic normally performed et rhc mill, at additional cost, end is

sometimes witnessed by an independent: testing laboratory. ASTH specification

requirements arc broader for check analysis than for ladle analysis.

Second, SIICR r.ust, as structural engineers for The I'orld Trade Center, review

the documentation of all certified aill test reports to assure that steel

eor.forms to the requirements of the Specifications. The procedure is not

involved, consisting of a careful cross-cheek of all documentation to assure

that all material used in the vorh has been tested and that the results of

tho tests COnfom to the requirements of the Specifications.

Third, an independent testing laboratory nay be retained to verify, to the

e::tent cooned necessary by the Chief of the Planning and Construction Division

of The tforld Trade Center, the accuracy of the certified aill test reports by

x-'itnessir.g tests made at the manufacturing trill. All vork performed by' the

independent testing laboretcry should be accomplished on a rancors sampling

basic. In the event that, through the sampling techniques, instances of

moncoaforming notorial arc discovered," the number of tests witnessed should

be increased, as should the number of check analysis tests requested

.

Conversely, if, as is to be expected, the sampling technique proves the mill

test reports satisfactorily represent the notarial and conform to the

ipeeifications, tho percentage of tests witnessed may be reduced. The ncr.be

r

of tests witnessed should not, in any case, be reduced below 5 percent,

!'itaessir.g of tests should be performed on the basis outlined belev, firct

fc- itar.rey Pacific material, and then for Pacific Car and Foundry material.

Stanray Pacific

Contract WTC-217.00

(includes ASTM A3C and F

y

- 42 ksi steel)

1. Chemistry

a. l.'itness S percent of nhe ladle analysis teste performed by

the mill to assure conformance with ASTK A6 and tho chemical

requirements of the stcol specification.

326 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SK I LL1 N 6 - HELLE-CHRISTIANSEN — ROBE RTS O N

b. I-?! amass 25 percent cf the check analysis tests performed by

the mill to assuro ccr.fom-r.ee with ASTM Ac sr.d the requirements of the steel specification. Steel to be subjected to check analysis shell be selectee by the independent tooting

laboratory ana should represent about one out of each si:c heats from which steel is supplied for use in the work.

2. Physical Properties

c. Uitnass 10 percent of tensile tests performed .by the sill co assure corforrar.ee to the requirements of tho cteel specif icacion,

AST:-: A6, and the applicable portions of ASTM A370.

b. V'itness 10 percent of bend teste performed by the r.ill to assure conformance to the requirements of the steel specification*

ASTM AS, and the applicable portions of AST?: A370.

2. Conditioning

o. Should the manufacturer elect to repair plates in accordance

with ASTM A6, the testing laboratory dr.ov.ld witness 100 percent

of the conditioning work to assure conformance to ASTM A6

.

•i. Marki=s

a. The testing laboratory should check the markin3 of steel plate

for conformance with AST>! Ac and the Specifications, and for

proper representation on a certified mill test report.

Pacific Car end Foundry

Contract VTC-214.C0

1. Chemistry

TCitncss 10 percent of the ladle analysis tests parforr.ee by the

mill to assure conformance with AST?: Ac or ASTM A20» as applicable,

and the chemical requirements of the steel specification.

"..'i races 25 percent of the check analysis tests performed by the

mill to assure conformance vith ASTM Ao or ASTM A20, oc applicable,

and the requirements of the steel specification. Steel to be

subjected to check analysis should be selected by the independent

testing laboratory and should represent about one out of each four

heats from which steel will be supplied for use in the work.

NISTNCSTAR 1-1A, WTC Investigation 327
Appendix E

SKI LL1 NG - HELLE- C H R I STf ANS £N - ROBE RTS O N

2. Physical Properties

a. . t:itr.ess 15 percent of the tensile tests performed by the ssill to secure cocfcrr.ar.ee to the steel specificotion , AST!-! A£ or

ASTh* A20, os applicoblc, end to the cpplicable portions of

.-.Sr.: A370.

b. Ui.ts.zzs 15 percent of the bcr.d teste performed by the aill to assure cor.fomor.ee to the steel specif icotior., AST;'. .'.6 or A57M A20, os oppliceble, end to the oppliceble portions of

A370.

c. tCitr.ess 20 percent of the Chnrpy ir.ptct tests performed by the

sill, there required by the steel specificotior..

d. Witness 10 percent of the Srincll Uordr-css tests, where required . by the steel specificotior:.

e. VJitr.ess 10 percent of the f.ro ir. sioc tests, where required by

the steel specificotior..

f. '..'irness oil rctcsts, vherc ollove.d by the steel specif icotior;,

3. Conditioning

o. Should the msmufsecurer elect to rcpoir pistes in sccordonce with

A£7M AS or AS?>: A20, os oppliceble, end the provisions of the

steel specif icotion, the testing Isborotory should virncss oil

conditioning vorh to nosure conforoxsr.ee to the oppliceble

specification requirements.

a. The testing loborotcry should cbcoh the morkir.p of steel ploto

for conformance to AST!-: A6 or ASTX A20 end the Specifications

,

one for proper representation on o certified r.ill tost report.

5. Distribution of Samplinc

o. The pcrcc-ntr.^es of senplir.r; outlined above refer to the total

amount of steel requires for Contract l.TC-214.00. Proportionately., norc of the sampling should be applied to the higher yield point

materials, with the greatest density of campling applied to the

quenched end tempered steels.

328 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKI LLING-HELLE-CHRI ST IAN SEN-ROSE RTS O N

- 5 -

Leer, but cf priro irportcr.cc, tV.c structural steel fabricator r.u;: assure hiscalf that ell creel coafc-raa ro the recuiraaents of the Specif icctiocc.

The tcbricetcr ehculd do this through the review of :till test reports,

checking of riteriel csoinst the r.111 tost reporta , aac the pc-rfortter.ee

of additional tests vherc the fabricator deer.c roccssary. Is addition, the

fabricator r.uct check ell -plate for correct dizcasioas, satisfactory finish

end frecdea free unacceptable lac:inatioas.

Very truly yours,

5KHLIKG-^E1LE-CEKIS"IANSEX-RC3nR7S0r:

Leslie Lofcerzsoa

NISTNCSTAR 1-1A, WTC Investigation 329
Appendix E

THE TORT OF N£W YORK AUTHORITY

111 f pghih Avenue-it ISlh Slnr!, New Ywk, N.Y. 10011 Construction HacBSer'fi Offic*

30 Church Street • Rs. 1119

Hev York, Hn# Y rk 1000?

Mifcoim P. Levy, thtri, Pl.w>»ng i Cor>»tryciion~OiYliion

S. M, Morili, Contlraciwn M*iM(n '-'-irfiow <TW W0-^I1

Woi Id Trade Department

Guy.F.Toizoii, d<to

RiChjrd C Sullivan, r»f<ne<. T^c ivortd Tf,d« Cmtrr pa

September 21, 1967

Stanrey Pacific Corporation

11633 South Alameda Street

Los An^clce, Califoraia. 90002

- Attentions Mr. tt. E. Morris

Sol The Uorid Trade Center - Contract WTC-217.00 - . far En»t Sunfrlmrndonce Co.

Cc&tloseni

In reply to your letter of September 12, 1967, the international inspection agency, Superintendence, Inc., of Key York City,

through their affiliate f Iras in Japan and Great Britain, hove been

retained to provide the foreign mill loapection. This Inspection, in

Addition to providing the normal review of mill test reports end visual

inspection of material prior to chipaent, Includes! o detailed check

for <liacacienai tolerances performed on a random basic on a minimum of

101 of the plates and 201 of the shapes; the witnessing of a oiainum of

10% of the chemical testa and between 10Z and 201 of the physical testa performed by the mill as required by tho specifications; independent

check analysis on saapleo from 102 of the hears; and witnessing 10% of

the loading of material aboard the carrying vessel to c&cure proper storage.

ror Information, and la the hope of belnp. of soae ascistanco

to you, Superintendence has been instructed to furnish you with copies

of all inspections end reports made on mater laic furnished under youc contract. As you ccn ace from tho above, they do not perform 10Q1 inspection and thus, In most cases, would act be in a position to Inform you cf

material shortages.

Our mill inspection date not relieve you of your obligations

330 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

£t«ar«y Pacific Corporatioa - S«ptrober 21, 1967

Acttatiooi Wff. R. g. Wosria.

under the eubjccc coaCract. dovevcr, >vi -will cootiaua •» aacvt co offer aay assistance ve caa*

"

Siocarcly,

a. «. Koati

CoootcdcCioa Kaaager

The World Trade Ceatar

Copy cot Kercrs. J. R. Ecdlcr (TECC)

- R. Van Scolk (Superinteodecc* Co.)

t.S. Sober caoa (SECR*

NISTNCSTAR 1-1 A, WTC Investigation 331
Appendix E

THE PORT OF /NEW YORK AUTHORITY

Wot Id liadc Department

M.llfnlm P. Irvy, fhiH. fi»«>»'«« A f*>mt«ir«ia» nivhfcin K.M. Mnnli rv«»«iwri(ra» M»»»|t««» t#>f|»»«««» <?1JI JfT-rwrt OKirf «t t~— • >...•.. ». M.njfrt W 0»«'t*» Si.. Nr» Vml. N.V WTO?

November 13, 1967

Stanray Pacific Corp.

11633 South Alameda Street

Lob Angeles, California 90002

Attention: Mr. R. £. Morris

Subject: WORLD TRADE CENTER - CONTRACT WTC 217.00 - MILL INSPECTION

Gentlemen:

As you know, the Port Authority as part of its overall quality control

program on fabricated steel for the World Trnde Center, has established

s policy of providing mill inspection at all sources, whether foreign or domestic. The scope of this inspection include;? independent checking of rlt-mtcal and physical properties on a random basis. In order

to imp]»-m- nt this program, each fabricator bar. been requested to have

their suppliers make available to our inspection agency, extra samples.

Our inspectors will collect a representative percentage of these samples

for independent testing. Some of the testing will be performed by the

agency inspecting at the mill, and in the case of foreign sources, some of the samples will be forwarded to the United States for testing.

The independent testing portion of the mill inspection program will be

performed as follows

:

A. Domestic Sources

1, Steel with yield points less than .r>0,000 psi - One tension

tost and one check aualysiu un s (imp leu selected at random

from I out of 10 heats.

2. Steel with yield points of 50,000 ps t and higher - One

tensile, one bend test and a check analysis on samples

selected at random from 1 out of 10 heate.

332 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Stanray Pacific Corp. November 13, 1967

3. Foreign Sources

1. Stool with yield points loss than 50,000 psi - One

tension test and one check analysts on samples selected

nt random from I out of 10 heats to be performed abroad.

In addition, one sample suitable for a tension test

from 1 out of 4 heats will be shipped by the Authority's

Inspection Agency to a laboratory In the United States

for tensile test end check analysis.

2, Steel with yield points of 50,000 psi and higher - One

tensile test, one bond test and n check analysts on

snroplce selected at random from I out of 10 heats to be performed abroad.

In addition one set of samples suitable for machining

into a tensile specimen and a bonding specimen will

be selected at random from 1 out of h boats and will

be shipped by tbc Authority's Inspection Agency to n laboratory In the United States for further testing.

It con be seen from the above, that basically the samples fall into

two catsgories:

1, Steel with yield points below 50,000 psi in which case only a sample suitable for machining into a tensile test

specimen will be required. (Check analysis specimens can be obtained from the tensile sample.)

2. Steel with yield points of 50,000 psi and above, In which case a set of samples suitable for machining

into a tensile and o bend specimen will be required.

(AgAin check analysis can be made on the tensile ' sample*)

The only difference between foreign and domestic sources ir, that on foreign steel a larger percentage of the total number of heats will

be tested. Kindly reinstrue t your supplier and request that they

confirm their concurrence to supply the required samples. Since the

unmachincd samples for independent testing ran be obtained by the

mill at the seme time that they take their samples for testing as

required by the applicable specification, no additional handling will

be required and uo additional costs should be Incurred. If you think

It advisable, I have no objection to your forwarding a copy of this

letter to your suppliers.

NISTNCSTAR 1-1A. WTC Investigation 333
Appendix E

-3-

Stanrny Pacific Corp. November 13, 1967

Kindly implement the above procedure immediately nn .nil present and

future mill orders and plcnsc keep the underpigned ndviscd on any

problems that you may experience.

Very truly^yours

,

/<> R.ll, Monti

Construction Hanngcr

The World Trade Center

CC: J. Endler (TRCC), L. Roberteon (SClSl), M. Levy

334 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

TLH OOP >>*

!i)»] tr, I Pitts burgli-Des Moines Steel Company

i

i /-../•nt.i/.i/v | NIVIllI Sl*NO • PIITSOIIOCM, «IH»5HV»NI» • A 1} E » tOOt *tl PHONC J..-5O0C

October 21, 290G

Tislir;a- Hcaitv and Construction Co., Inc. OC? Fifth Avenue

Mr "ork, New Tork 10019

A* n : Xr. James P.. Eadlcr,

Assistant Vico President

Reference: The Forld Trado Center

Quality Control r.r.d 7c<tinr; Progrnia

Structural Steel - Pcckcpge I, III IV

Tro arc pierced to trcr_sr:it Lore—itb our f<roposcd

Quality Control nnd Tec t inn Pro£r:»i3 Tor Pnck.ijer. I, !ZI

nnc3 IV of the Project. Wo Till appreciate enrly review and

comcrt on tela ProsTan co that nny adjustments r.'hicl: cr.y dosircd can be incorporated into our proposals.

We have bad to tvake inportant assumptions ns to tho

ar.ount of rad iojrophic or ultr-30Dlc teotinp; of <rcld3 tfhich

will be required to cointain acceptable quality throughout

tho ;rork, Ticreforo, the r.tiount of such testing epoo.tfled

in the enclosed ProgrnE is not nn expression of Judjpaent c:

our part as to whether said nnount of tooting will rvarantee

a quality level conai3tect with the service required.

Responsibility for this jv.Cryzont resto with tho Ovzox . Generally, our veld quality control prosren i3

based oa the "spot-cxaslnat ion " principle The quality of

rcldir.fj produced to meet npot-cxaninDt ion roqulrerr.cn t.*» Trill

approach thut vbicb would be produced for 100 percent iiii?.p-«i:ticn

.

however, spot examination rvill not Insure nnr-'x of predeterm ined

quality levol throughout, end work acceptod under cpotojfDcieatlon roqulrpmentH ni«»y still contain defects "sbich 1 bo disclosed under further examination . If nil unacceptable

wold defects which would be revcalod by rndloer'sphic or ultrasonic inspection csust be eliminated from the sti'uetur-c or specific portions thereof, then 100 percent inspection

cuat bo oaiployod, and oust be included as n i" actor in the

cost of production.

HAMMOND PRODUCTS

NISTNCSTAR 1-1 A, WTC Investigation 335
Appendix E

C»Mf <-iTT0tM0iN

LjJ^ Pittsbxirg*h-Des Moines Steel Company

Fiihrictitttn Cimstruclofs \ fHONt S3I-J0O0

November 28, 1066

Tishm.m Realty and Construction Company, Inc.

G66 Fifth Avenue

New York, New York 10019

Attention: Mr. James R. Endler, Ass ' t . Vice President

Reference: The World Trade Center

Quality Control and Testing Program

Structural Steel - Packages I, III k IV

Amendment No. 1, dated November 25, 1966

Gentlemen

:

Enclose! is A-senO^ent No. 1 to our proposed

Quality Control nnd Testing Program for Packages I, III L

IV of the Project. This Amendment is submitted in response

to the Worthington, Skilling, Uelle and Jackson letter dated

October 27, 196G. With reference to the comments listed

in that letter, our acticvj in each case has been as follows:

Information contained in the first

comment has been incorporated into our program by revision of paragraph

SP-5 .03, Supplemental Provisions.

Ao organization chart for the PDM

Quality Control Department has been

added as Appendix A to the program.

Qualification standards for testing

personnel have been outlined in added

paragraph Sr-1.05.

Paragraph SP-5.11 has been added to cover ultrasonic testing procedure.

ASTM aud AWS standards have been

referenced by revision of paragraph

SP-5. 04, and addition of paragraphs SP-5. 12

and SP-5. 13.

1.

2.

i

4.

5.

HAMMOND PRODUCTS

336 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Pittsburgrli-Des Moines Steel company

C. Description of production methods,

jigs, templates nnd other means

of dimension control have been added

as Appendixes B, C and D, and paragraph SP-6.03 has been added referring

to these appendixes.

7. Paragraph SP-4.02 has been revised

to provide for material delivery in

accordance with ASTM AG and A20 both.

8. A statement regarding life of the proposed painting system has been added as paragraph SP-8.05.

9. Procedures for cutt ing, de-burr ing and

edge preparations for welding have

been outlined by revision of paragraph

SP-4.05 and addition of paragraph SP-4.06.

10. Paragraph SP-5.10 has been added to describe the use of welding procedure

specifications and Joint welding procedure

qualification tests in quality control work.

This Amendment No. 1 also incorporates a revised sec Lion on KDciogrnpnic Inspection into the body of the- PDM

Quality Control Program. This revision was completed shortly

after our original submittal of the Program.

We hope this Amendment will be considered satisfactory ^-espouse to the concents on our Program, and that the

Program may therefore have final approval. Vie will be pleased

to discuss the matter further; however, and will make any

additional changes which may be deemed Decenary.

Tishman Realty and Construction Co., Inc. Nov. 28, 196G

Page 2.

Yours very truly,

PITTSBURGH- DES MOINES STEEL COMPANY

James C. Dods

,

Special Products Depax*twent

JCD/k

Atts.

NISTNCSTAR 1-1A, WTC Investigation 337
Appendix E

C*BVt: MtOtHOW

Pittsburgh- Des Moines Steel Company

f.ii'/n.-.-rs Fahricntorx Conntrurlors mnue island PITTSBURGH. PINNSTLVANU 15125 • arc* cooe *l» PMONC 331-3OO0 December 23, 1966

Tisbman Realty 6 Construction Company, Inc. 666 Fifth Avenue

New York, He« York 10019

Attention: Mr. Janes R. Cndler

Reference: The World Trade Center

Duality Control and Testing Program

Amendment No. 2 Gentlemen

:

We acknowledge receipt of the Korthinp.ton, Shilling, Helie f, Jackson letter dated Decenbcr 20, 1966 re- sardine our Quality Control Program for the. World Trade

Center. In accordance with the .statement therein that

the text of the Program "should be changed", and in com- pliance with your request by letter dated December 21,

1966, wc submit hcrev.-ith Amendment No. 2, revising our Program to incorporate the items called for by the Engineers, and we will proceed to evaluate our earlier proposals to determine what influence this change may have

on them.

Yours very truly,

PITTSBURCH-DF.S MOINES STEEL CO,

JCD/k/lsb

Atts.

HAMMOND PRODUCTS

338 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

.PITTSBURGH- DBS MOINES STEEL COMPANY

QUALITY CONTROL AND TESTING PROGRAM

THE WORLD TRADE CENTEK

AMENDMENT No. 2 December 23, 1966

The Pittsburgh-Des Itoincs Steel Company Quality Control and

Testing Program for the World Tmde Center, dated October 19, 1966

vith Amendment No. 1, dated November 25, 1966 is revised as described

hereinafter in response to letter dated December 20, 1966 from

Worthington , Shilling, Helle & Jackson to Tishman Realty and

Construction Company. This Amendment also includes correction of a typographical error in the original Program.

1. Under Section SP-5 WELDING, delete paragraph SP-5.05 on page S-5,

and substitute therefor the following:

SP-5.C5 riilet welds will be inspected as follows:

a. At least fifty percent (50%) of all fillet

Telds on quenched and tempered steels will

be subjected to magnetic particle inspection

48 hours or more after welding,

b. At least ten percent (10%) of all fillet

velds in steels other than quenched and

tenpered steels will be subjected to magnetic particle inspection.

2. In Amendment No. 1, Paragraph SP-5. 04, Change the first sentence

to read as follor.s: "Inspection of welding by PD11 Quality

Control Personnel will conform to the requirements of Section 6,

AWS Dl.0-66".

3. Under Section SP-5, WELDING, in Paragraph- SP-5 . 07b, ninth line,

Change "twenty percent (20%)" to "ten percent (10%)".

NISTNCSTAR 1-1A. WTC Investigation 339
Appendix E

tiXDZX Pittsburgh? Pes Moines Steel Company

l)lhr„ul,.i^ i •tEV "-^t ISlANO • PITTS8t>B0M PCKNSTI.VAMIA 13JJ3 . .OCA CODE 4H

»»0*C 5JI-3000

f t>n*trtn Uirx I

Juno 2, 1067

Tlahtnan Xonlty and Conotruotion Co., Inc.

C66 Fifth Avenue

Kow York, Hew Tork 10017

.Attention: Sir , Eorbcrt Coins toin

Roforonce: Tho ftorld Trade Center

Contract UTC-213.00

Quality Coctrol and Tenting Program

Gontlcnon

:

In response to th© lottor dntcd Jiny 16, 1961, from Mr. Jatuss TTbito of £klliing-H©llo~Chriotiansen-2obortGon, wo cube It herewith ilaondtzent No. 3 to the PDH Quality Control and Tenting

Prograra.

Socio explanatory ccssont le In order concerning tbo dltteasional

control and checking procedures ond tho revision to ParajjrRpb

SP-0.O3 in this A&antisent Hn, 3. Ur . White and myself discussed

this soattor by telephone on ilay 16, 1007 and due to that coavereation

it is ?siy understand ins now that tbo information desired here

should describe FCil Quality Control ivaart'^?r;t inspection procedures

ruiher raan actual work procedures as covorod by Appendix C.

Therefore, wo huvo omitted rcforonco to the Appendix and have

revised Paragraph 0 c 03 so thst it so? concern iS5pe€ iioa

procodurco. Since approved ohop drawings aro used for developing

thoso procedures, thoy cannot be described it this wife*. We hope you will find this submittal satisfactory, and that our

Quality Control and Testing Program may now be considered an acceptable reference for use with the executed Contract and

Technical Specifications.

7ours very truly,

pmssufcCii-DEs Eonreo steel cospas?

J. C. Doda,

Special Product o Department

Mta.

cc; Ur. Jaaos tThita

Ski11ing-Ka1

1

a-C-h rIstisasse~- Hcbcrtncn

HAMMOND PRnnrrrr^

340 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

PITTSaURGH-DES MOINES STEEL COMPANY

QUALITY' CONTROL AND TESTING PROGRAM

THE WORLD TRADE CENTER

AMENDMENT KO. 3 JUNE 1, 1967

The Pittsburgh-Des Moines Steel Company Quality Control

Program for The World Trade Center, dated October 19, 1966, with

Amendment Ho. 1 dated November 25, 1966 and Amendment No. 2 dated

December 23, 1966, is revised as described hereinafter in response

to letter dated May 1G, 196? from Skillins-Helle-Clu'istinnsenRcber tson

.

1. In ParaGraph SP-5.03 on page 5 of Amendment tfo. 1, delete the

entire last sentence: "The complete penetration butt velds....

bridpe quality welds." and substitute therefore: "The complete

penetration butt v/elris at the tops of the ninth story spandrels

will conform to AV/S D2.0-66, Article 409."

2. In Paragraph SP~5.11 on page - of Amendment No. 1, delete the

entire first sentence: "Ultrasonic inspection .... of weldr.ients .

and substitute therefore: "Ultrasonic inspection of v.-cldments will be governed by ASTM Standard E164-65, Standard Method

for Ultrasonic Contact Inspection of T.'eldments , and by the

PDM Quality Control Manual Section entitled Ultrasonic Inspection.

Where there arc conflicting requirements, the provisions of ASTii

Stnndard Z164-G5 will govern".

Also in paragraph SP-5.11, delete the entire lr.st sentence:

•'(The PDM Quality Control added when complete)".

NISTNCSTAR 1-1A, WTC Investigation 341
QUALITY CONTROL AND TESTING PROGRAM

THE WORLD TRADE CENTER

AMENDMENT NO. 3

PAGE 2.

6-1-67

3. In Ancndi'icnt No. 1, page 7, delete Paragraph SP-6.03 entirely

and substitute therefor:

SP-6.03 PDM Quality Control Personnel will perforn such

inspections and dimensional checks as they consider

necessary to maintain proper control of dimensions and

to insure production of column panels which comply

with the Specifications and meet the tolerancesdescribed therein. Procedures governing control and

inspection will be developed to n-.cot the requirements

of this Contract, based on approved shop drawings

.

4. In Paragraph SP-1.03 on page S-l of the original Program,

delete the entire sentence: "This PrograB.,.. of the Project",

and substitute therefor: "This Progran will govern Structural

Steel Fabrication for Contract 1VTC-213.00, Fabricated Steel,

Exterior Wall frorn Elevation 363 to the ninth story splice,

North and South Towers".

5. In Paragraph SP-4.0C on page 4 of Amendment Ho. 1, in tha

eleventh and twelfth lines, delete the worts ". . . . to the

satisfaction of PDi; Quality Control Personnel".

6. Attached is PDM Quality Control I'.anual Section entitled

Ultrasonic Inspection dated 12-15-16, which is hereby made

a part of this Quality Control and Testing Progran.

NISTNCSTAR 1-1A, WTC Investigate
Supporting Documents for Chapter 6

U - 1 GENERAL

U.l.l

U - 2 HETHODS

I' -2.1

U.2.2

U - 3 EQUIPMENT

U.3.1

U.3-2

B.3.3

U.3.I1

12-15-66

1-D-e

Page 1 PITTSBURGH-DES MOINES STEEL COMPANY

QUALITY CONTROL MANUAL

NON-DESTRUCTIVE TESTING

ULTRASONIC INSPECTION

This is a procedure for ultrasonically testing and inspecting

velds for internal discontinuities by the reflection method using pulsed waves introduced by direct contact of a search unit with the veldment.

Shear Wave Testing

Shear wave inspection shall be performed to a 33! notch sensitivity. Tne test is curiuucteo u6lii£ »ri^lc projection

transducers L5° to 85°; the selection of the angle being

dependent on either or both the thickness and the georvetry of the weldment.

Longitudinal Wave Testing

Longitudinal wave inspection can be performed to a near 100% sensitivity with a i/h micro-inch surface finish and

at 2^ mc, otherwise satisfactory results depend to a larg*? ortent upon the cc.idition of the test surface.

Electronic apparatus capable of producing, receiving and displaying high frequency electrical pulses at frequencies

of 1 to 2.25 rac is normally satisfactory for most welds.

The search units shall be capable of reversibly transforming

electrical vibrations to sound vibrations within themselves

ob well as transmitting and receiving vibrations in the material being tested.

The couplant between the transducer and the test surface shall have good wetting properties end shell be selected, if conditions permit, from the following list:

Oil Glycerin Silicones Water Orease White Lead

Reference plates will be provided for determining and checking instrument sensitivity, for instrument calibration

and for comparison with defect indication. Each plate shell

have artificial defects and ell defects permanently marked.

NISTNCSTAR 1-1A, WTC Investigation 343
Appendix E

12-15-66

1-D-e

Page 2 ULTRASONIC INSPECTION

V - U SURFACE PREPARATION

U.li.l - Hot rolled surfaces require removal of any loose adherent

scale or other foreign matter. Conditioning of tne surface can be accomplished by sandblasting, grinding or belt sanding to provide st least a 250 RMS surface finish.

U.ii.2 - The base material surfaces to be used for inspection shall

also be cleaned of weld spatter and roughness on each side

of the weld for a minimum distance of six (6) inches. w"eld surface irregularities which are beyond the normal patterns,

shall be removed from both the inside and outside surfaces.

The deposited weld metal shall merge enoothly into the base

wetal without undercuts, sharp ridges, or valleys.

U - S ULTRASONIC INDICATIONS OF WELD DISCGHTiyUTTIES

U.5.1 - The maximum magnitude of a signel indicating e weld discontinuity shall be recorded as a percentage of the <i«ighl of

the signal from the hole in the reference weldment. The

height of the signal is some indication of the size of the

discontinuity. This method of estimating the size of the

discontinuity shell be used when flew dinenMon is smaller

than one-half of the dimension of the crystal.

U.5.2 - A reflection that is always visible with movement of the transducer transversely to the discontinuity indicates

depth which rr,£j be measured. Likewise e reflection that

i« ci-jay*. v^«ih''» with movement of the transducer longitudinally to the discontinuity indicates length which con

also be measured. This method of estimating the size of

the flaw shall be used when the discontinuity dimension Is

larger than one-half of the dimension of the crystal.

0.5.3 - Locations of the flaw with respect to the surface of the

plate are determined by the position of the signal on the

tube and the location of the transducer with respect to

the weld.

U.5.I1 - Flaws in base metal are possible sources of misinterpreted

indications. These areas will be searched with normal

incident longitudinal wave test methods to determine the presence of such imperfections.

U.5-5 - Small reflections from the weld area are generally apparent

to indicate that the sound is penetrating the weld.

U - 6 PROCEDURE FOR CHECKING BUTT WELD DKCONTINUITIES

U.6.1 - Discontinuities longitudinal to the weld, move the trans- ducer slowly to and fron the weld with mainly a transverse

{with respect to weld) movement end at such e rate that the

operator can clearly see and identify the signals. The

transducer should be rotated slightly in the plane of the

motel *iirfpc«» in both directions to obtain maximum signals.

344 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

12-15-66

1-D-e Fage 3 ULTRASONIC INSPECTION

Use just enough longitudinal movement to advance the transducer parallel to the weld no more than one trans- ducer width per transverse cyclo. The total minimura transverse movement should be sufficient to fully cover the entire cross-section of the weld. Normally check both

aides of the weld from joju^ surface only, but in spe*. : al coses a more corrplete investigation from both surfaces is required.

U.6.2 - Discontinuities Transverse to the Veld

If the weld is smooth, and satisfactory contact can be made, move transducer slowly along top of weld with the ultrasonic

beam parallel to the weld. If satisfactory contact cannot be

made on the weld, place the transducer on the base metal surface

at the edge of the weld, and angle the transducer slightly to

obtain the same effect, move the transducer at such a rate that

the operator CBn clearly see and identify the reflection.

U.7.1 - Branch or nozzle, flange to shell, corner and other full

penetration welds can be inspected with an angle beam

using procedure in U.6.1 or U.6.2 above, when the methods

are adaptable to the geometry of thfc weldment.

U.7.2 - Inspection of fillet welds, attachment welds, and other welds

not requiring full penetration can be generally inspected

with an angle beam by procedures in U.6.1 or U.6.2. The

ri^y-.cl srsst be csr^fslly Jiotingulshed to avoid interpreting

reflections from the geometry of the part as being indications

of discontinuities. In all scanning, if a defect indication

is obtained approaching in amplitude that of the reference

plate, the adjacent area shall be scanned sufficiently to establish the size and location of the dtaeontiniuty.

U - 8 STANDARDS FOR ULTRASONIC INSPECTION

U.8.1 - Any crack, lack of fusion, incomplete penetration, inclusion, or cavity which is indicated by a reflection equal to or

greater than 90 per cent of the applicable reference hole end which has a linear dimension as indicated by the transducer movement exceeding:

l/b, inch for thickness up to }/h inch. 1/3 of the thickness for plate 3A inch to 2-lA inch.

3/h inch for thicknesses over 2-1/k inch.

is unacceptable.

U - 9 REPORTS OF INSPECTION

U.9.1 - The report of ultrasonic inspection shall be made after

re-inspection of any areas requiring weld removal or weld

repairs. The reports contain the following information:

NISTNCSTAR 1-1A, WTC Investigation 345
Appendix E

12-15-66

1-D-e

ULTRASONIC INSPECTION

1. Inspection dete.

2. Instrument settings.

3 . Height of general signals from parent metal and

deposited netal.

U. Purchaser's order number and droning number.

5. Sketch conteining physical outline of weldrcent vith location of repaired areas.

6. A table of the inspection results coordinated with

a sketch estimating size, length, depth and location

of flaws.

346 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

World Trade Department

Cuy f. lo.'ioii. BWvtei

Vj!<Oim f. iwy. f '. rtemun* .\ Cmu««a D....o»

K. M, Militia. C.H-.^'w<t-iM» \vt«> fc *-t l.-irpi-one :.-7-.V«n Ou«<r « Cmuiihiumi mx<u£«j BvOumVM. v,.ii..\ t «c;

March 11, 1963

Pittsburgh -Dcs Koines Steel Company

Neville Island Pittsburgh, Pennsylvania 15225

Attention: Mr. H. M. Fish

Re: The U'orid Trarit- n<>r,r^r - Concrsct VIC 213.00

Vel<!ir.2 Procedure Specification:

Gent lcscr.

:

This wiLl conrira approval of your submitted "Voiding

Procedure Specification 1>B 119-172 (VvTS-1)", revised February,

1966, and Joint Qual if icat ion Sheets SA-3. 56-30, 58-36, 5S-42 , 6C-35, 62-2 and 62-80, ;s noted on SKCR letter dated February 26,

?.. Ha Monti Con a cruet lor. Manager

The World Trade Center

0

Crar.er (RUH)

White (SKCR)

NISTNCSTAR 1-1A, WTC Investigation 347
Appendix E

"CQ3"2D. Pittsburg'h-De s Moines Steel Company

February 15, i960

Mr. R, M. Monti

Construction Nianacjer

ROOHi 1119

The Port of New York Authority

30 Church Street

Nevj York, New York 10007

Gent lc pen

:

Enclosed herewith please find two (2) copies of Welding

Procedure Specification DB119-172, WPS1 revised in accordance

with Mr. Janes White's consents- In his iVjttcr of December 19,1957

to Mr. R. M. Kant t $ and, our Nr. A. C. icgan's telephone con-, vcrsation with Mr. Jostein ?Jes on February 12, 1968.

In response to comment t'o , 13 of Mr. Whites? letter, joint

W* is noted to weld in the flat position and is prequalificd

according to AWS D1.0 and D2.C. We assur.e that the reference was intended for joint MS. Easoi on this assumption joint US has been voided.

Also enclosed are additional welding procedures and

qualifications fox your consideration. Procedure SA3 is a combination manual- submerged arc joint, approval of which was given by Mr. Kes. Joint qualifications 56-20, 50-26, 50-42,

60-25, 62-2 and 63-80 are all previously qualified joints

which tre feel have the prerequisites for use or. this contract

.

Rc The tferld Trade Center

Contract WTO 21 3. 00

PDM Contract 17078 O 17130

HAMMOND PRODUCTS

348 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Piusburg'h-Des Moines Steel Company

- 2—

I'JC P. M. }-Sonti

The World Trade Center February IS, 1968

Welding on this phase will start shortly so your early

consideration of the above items will be appreciated.

Very truly your:;,

PITTSBURGH- DES MOINES STEEL COMPANY

H . M . Fish, Project Manager rw

cc : Mr . H, A. Tessler

Mr. Al Guttentag

n/one copy ox* Dijli9-l'/'2

Skilling-Hellc-Chris t iar.scn- Robertson

Attn: . Janes White

v;/one copy of D2119-172

NISTNCSTAR 1-1A, WTC Investigation 349
Appendix E

SKILLING - HELLE-CHRlSTlANSEN - ROBERTSON

Consulting Structural and Civil K«»mvts • 250 Park Avphkc, New Vnifc, N V H*JIT Ma 0 \s'|

(ohn B. Skilling llclv.' j llcilc • /*•/,> V Chmtkwten • Ixtik V. Ruln-rivm

February 1969 Cwwtow*.

Port of Nov YorV Authority

Office of the Construction

Han.ap.cr - Poena 1119

30 Church Strcot Now York, Kev VorV 10007

Attention: Mr. R. M. Monti, Construct Icr. !'^n:-:r

r.cdfererxo i The Vorlrf Trade Cantor

Concrnrt WTC-212.CC, PlttaVurgh-Dc* Koie'e* wcSdirsa Procedure Specif icetisa 119-172 fUPS-l?

«oa5 joint OuelJ f JcatioTi«

GvSlt Ivnon :

Ve have revicved the FL'M letter Aatfd February 15, 1968 end approve Volriln;; rrocedure 2p2cl f lea t icn D3 119-172 (VPS-1), revised February. 196(5 in It* prcoent forw, and aIco rtpprove Joint qualification sheets SA-3. 56-30. 56-36, 53-42, 60-35, C2-2 niyj C2-f?0.

We underotand that TDK 1c not jjoIur to ojstfloy either Joint HA or MS doncrlbtrd lii tij-? Joint v«l<iinj» procedure aheats included vlth their

previous eubaltta-i of vcldlnp, procedurcn and Joint qualifications.

Vory truly youro,

SKILMSG-ltniJE'-CBtUSTlANSDI-FOSSS.TSOa

J«ss6a viiitc

f.r. B,

Mr. L.

h. pioh. pom

c. FcirS. r't~i*.

c ;, »»ni. <

350 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter

£P EXu<-) Pitts o*iir:?*li-]D-33 IvCo^ilss Stool CoiH^s.irv

....>,!.....» pxOKC JSI-iOOO

r>v.iA(iT.<'.'t /r.v ;

Construction JCmaccr

Hooa - 1119

The "or* of New York Authority

20 Church Street

K2W York, New York 1C1C7

£h<a l.'orU ".Trade Center

Co.TCTiCv I. TC- 21 3. GO

Ccn-.--cV i?C'7S i 171.%

Gcr.tlcs:

'..r ere c~.r.^*i.*.n y.ov ; ? • a^._; riv-'i-l t ; ;o t'li couic-r- or nur vrii - .c^.- -oz JO'i r"z .1* i^vi^cc i-iisch c , .1963. Cnc_: c joir.:.- shov.lc he rrcr a pirt of cuj: Welding Procedure

Specif icccio.n D;:,il9-172 su'o;;l'wt.id to you with cur letter of

February 15, 1-113.

'lcc.ee let u~ hive youi" tvproval of joi.-.tc X-5 end M5

,ery tri._y yours.

-IVTSEolCI-yDES KOIVSSS STliE;

s y... s -(/

cc: . ... re=cicr

Yz.7i±>z<.: . .'-'rejee- ?ie,nnir.c; Tiia 1-cr? of N. Y. .5.u

-:horit;/

";OCC! 3C0

vcrx. isev.1 yori: Oil

. V . _r.l - Gu1 1 c n « o z

'Herman Rcal'cy C< Cone true" ion Co. 11th Floor, 30 C'.urch Street

I'zvj York, New York 1CC07

-.//one (1) copy of X'A & MS

NISTNCSTAR 1-1A, WTC Investigation
Appendix E

V^'r'. v.->;V, .«>•.': v n V . *,« N

HcUNKG PROCEDURE - 3UTT SE'JM

.wjwtiji ^aj^ .A7 . A36, A4-.'l •" AKS TYPt „5- U2„

?--rcq uglified by AWS 01.0 & 22.

0

Fillet j;c:i.'icj:ic-. ASTM A233

Finer "c:j! cuiiiUaXa , S?0i3 or E7C5S

&i>acij«< A.-; V.'c.'d SMUt Cai: .. 6a* isi Gii 5liciCcS A:c

oi .v-jiiipii p-si Multiple

- All_C£rbon and Lov; Alloy Steels

50,000 psi Yield

$i,-jJi er .V.»S!r?,'a Arc Sxnglc

V.'cisiR; due.-.: AC or DO

F.:t: Ticn!««i! „ C-r.€>. i no Stri~>

?«cfts: T..-..(.t.i.o!c As acquired by M&iCgl&l Thic.<

.°;j»cj! Tc-;::::.:c 7.''P

nc

SKILLlfiG - HcltE OtiHSTlAflSEM-ROSERfSON

fV a:p;ov10

ct!-j ev.tt Q iQiCT'.O

352 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

PDM :

PITTSBURGH-DES MOINES STEEL COMPAN Y

Auooct 23, I960

ftr. R. P.. r^r.ti

Construction Meager

Kooci - 2119

The Pert of l-'cw York Authority

30 Church Street

New York, T'ct? York 1O007

Ho: The World Trade Centor

Contract •.VTC--212.00

PE?I! Centrort 1707b r, IVI3<i

G=r-tlcsen

:

i.'c 3wS,»i:tir.; fcr your approval two ("} copies of our rrclcino procedure r,ualiiic? ticn for jcintt C7-67, tly'ci. and" 67-70. Upon approval thes« joints v/ill becone part of our welclno procsdi:ro specification £3119-172.

I'Leasc return one (1) copy staapod with the engineura

approval or notify us by letter of your acceptar-ce,

very truly yours,

PITTSBURGU-DES KOINES STEEL COMPANY

II. M. Pish, Project hixna^cr cc t Skilling-Jlelle-ChriBtianson-noccrtcon

Ti'cw York, Now York 10007

Attn: Mr. Jascc Whito w/one (1) copy of joints

Kr« fil -ut'.^.itr-.c- Tishman Realty & Construction Company

11th Floor, 30 Church Street

Mew York, Nc\7 York 10007

ANNIVERSARY

NISTNCSTAR 1-1A, WTC Investigation 353
Appendix E

SKILLIN6 - HELLF.- CHRISTIANSEN - ROBERTSON

Cowvftio£ ...vctutat <mtf Civil EnginKts • 2:0 Potk Avcrti**, N*w Yotk, N. V, )00/7 • ,\f«, 9^'t7<

John B. SkilUttg • Utfge }. fklh ' John. V. Christiansen • Leslie K, isobedson

C0'trjf,-jti>( September 23, 1S68 • H«roM t. W'*»*M»s«}s

}ettf>h F, /cctfm

Port of New York Authority

Office of the Construction Manager

30 Church Street

Sew York, N.Y.

Attention: Mr. R. M. Monti, Construction Manager

Reference: The World Trade Center Contract wIC- 213.00, Pittsourgh-Dcs Moines

Welding Procedure Specification, D31I9-172

Sections WPS-1, WS-2, WPS-3

Centlemen'

We have reviewed PDM Welding Procedure Specification DBI19-172 , Sections

WPS-2 and WPS-3 as transmitted with the PDM letter dated May 22, 1968, as well as revised pages 3 and 6 of Section WPS-1, also transmitted with the May 22, 1968 PDM letter. Pursuant to our review, uc wish to comment as follows

:

I Welding Procedure Specification DB119-172, WPS-3

1. Page 1, paragraph 4 .0 FILLER METAL AND FLUX. The second senter.ee should be revised to read, "Materials for welding ASTM A51A steels to steels vith lower yield strength shall conform to the applicable provisions of DE119-172, WPS-1 or WPS-2, whichever

specification includes the lower yield strength catcrial".

2. ?E£c I, paragraph third sub-p.iragraph should be revised

to read, "A welder shall have in hie possession at any time only

th*>L quantity of electrodes which can be used within thirty

oiinutes after removal from the storage oven, and in no event shall

electrodes be used for welding A514 steels when the time of ex- posure to the air exceeds 60 minutes". This is consistent with

the recommendations found in the USS publication ABUSSOl-1205

titled "USS" T-l Constructional Alloy Steels", item 6 found on page 59 under Care of Covered Electrodes. .

r . . * . renin

MA.> *C(l'l"*Bt#

pKs*t»* t v«*»t«

V, X. P«ti*C»«T lint N , «es*»» WiilUK 9 . <- « » C I. J . WHtTl. iH.

9 « *- * T i. t O * t 1 C . 1 • a © W* I HI tOfi » V * i. O i =» C . ft f t T T k t , v*A»M(M«Tei> » • t e >

354 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKILLING-HELLE-C H R I ST I A N S E. N - ROBE RTS O N

- 2 -

3. Page 1, paragraph 4.1.1, fourth sub-psrapraph should have

on additional sentence added stating, "Electrodes which

cos-o in contact with water, grease or dirt shall be scrapped".

A. Page 2, paragraph 4.2, Submerged Arc Process, should have a second sentence added stating, "Flux for submerged arc welding shall be kept dry and if exposed to water, grease or dirt shall be discarded".

5. Page 2, paragraph 6.1 Procedure Qua 1 i flea tior.s . second sentence should be revised to read, "Procedure qualification tests will

be conducted, supervised, reported and certified by PDM and

s;ay be witnessed by an independent testing agency approved by

6. Page 2, paragraph 7.1, second e^nten-e should be revised to read. "Pe r t oraancc qualification tC6ts shall be conducted,

supervisee, reported and certified by ?£M 3nd s-«ay be witnessed

by an independent testing agency approved by the Engineer".

7. Page 2, paragraph 7.2, Welder's Certificate should be revised

to read, "FDM will provide for each welder or welding operator

a certificate or certificatec which indicate the results of performance tests and state the process and type of welding

for which the welder is qualified. Certification approved by Che Authority for each welder shall have been achieved within

a three nonth period preceding the date the welder begins

vork on Contract WTC-213.00".

8. Page ?, paragraph 7.2.1, should have an additional sentence

added stating, "When a welder has nor. performed welding

utilizing a given process for a period of 90 days.PhTA or SHCR oay require that the welder be requalificd for the process 2nd veldir.g positions in question".'

?. Psgc 2, ^ era^r 2ph S.i, second line should he revised to read,

with approved 6hop drawings, Specifications and welding

procedure"

.

10. Page U; PREHEAT AND INTERPASS TABLE should be rcodiflcd as shown

on the following " pagr..

NISTNCSTAR 1-1A, WTC Investigation 355
Appendix E

SHILLING - HELLE - CH RJSTIANSE.N - ROBERTSON

Page 3 September 23, 1968

*Thickr.es«

Manual Shielded

Metnl-Arc & HIG

Submerged Arc

Carbon Steel Wire

6 Allov Flux

**50 F. Min.

**50 F. Min,

150 ° F. Min.

o _ ...

**50 F. Min.

200

0

F. Min.

o

To 1/2" Incl.

Over 1/2" to 1" Inc.

Over 1" to 2" Incl. 150 " F. Min. 300 " F. Min.

Over 2" 200 ° F. Kin, 400 ° F. Min.

iiaxircuaj rreheat and Interpass i ercpereture 42:> F.

'Tbicknes? of thickest part st point of '-eld. "* Welding at plate temperature below 100" F. requires assurance

that moisture is not present in vicinity of joint.

11. Page 5, paragraph 13. A. 1, should be revised to read, "Bead

size and arrangement will be as shown in the Welding Procedure

Specification sheets for the applicable weld Joint, within the Units of permissible variations allowed by AWS Di.0-66 or AWS D2.0-66, whichever is applicable.

12. Page 5, paragraph 13.6.2, first sentence shall be revised to read, "Veld reinforcement as deposited will not be less than

flush nor more than 1/8 Inch, except that where applicable,

the provisions of Appendices E-l, E-2 and E-3, AWS D1.0-6&

shell apply",

13- Page 5," paragraph 13.6. Defects , fourth 1 i ne "should be revised

to read, "prescribed by the applicable provisions of the Specifications, approved PDM Quality Control Pro&raut and this

welding procedure specification, Those defects discovered

through non-destructive testing should be rctested by the* same non-destructive testing technique after the defective

weld c.etal has been removed and replaced".

14. Page 6, paragraph 14.1, second line should be revised to read,

''its the approved shop drawings, by symbol RT or UT, a minimum

of 1002 of the first 102.

356 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

5KILLIN6 - HELLE-CHRISTIANSEN - ROBERTSON

Page 4 September 23, 1968

15. Page 6, paragraph 14.1, second sub-paragraph should be re- vised to read, "Where the extent of defects so indicates, the Authority's representative may require that spot examination

of the affected welds be increased, even to one hundred percent

(1002) if necessary, until satisfactory quality is achieved.

Upon establishment of satisfactory quality, the rate of RT or UT inspection, tray be reduced again tc the specified percentage".

16. Page 6, paragraph 14.1.1, fourth line should r<»ad "Inspection".

Where there are conflicting rcqniresencri , the providers cf AW? D2.0-66 v»ill govern".

17. rave 6, paragraph 14.1.2, should be revised to read, " Ultrasonic

Inspection will be governed by PDM Quality Cor.tr&l M-ir.ual . Section i-D-c (revised 3-11-68) entitled "Ultrasonic Ir.ipeciicn,

P«S based or. "Appendix 'J, Ultrasonic Exan ir.se ion of Vcl<is (l! T)", pages i4-20 inclusive, of the "Winter 1967 Addenda, ASME Boiler

and Pressure Vessel Code, Section VIII, Unfired Pressure Vessels".

The requirements of Section UA-903 of the ASME Addenda shall epply

to the work.

18. Page 6, paragraph 14.2, third line should be revised to read, "MT inspected forty-eight (48) hours or more after welding".

II Welding Procedure Specification DE119-172, W?S-2

1. Page 1, paragraph 4.0 FILLER METAL AJ.D FLUX. Starting in the fourth line, add a new sentence stating "Allowable reoisture content and exposure tip.es stated in DB119-172, WPS-3. will, con-: crol whenever caterial under this specification ie joined to ASTH A514 steel".

2. Top of page 2, second line after the word "above" add a new sentence stating, "Electrodes which cone in contact with water,

grease or dirt shall be scrapped".

3. Page 2, paragraph 6.1, secend sentence should be revised tc read,

"Procedure qualification tests will be conducted, supervised,

reported and certified by .PDM and may be witnessed by an in- dependent testing agency approved by the Engineer".

4. Page 3, paragraph 7.1, second sentence should be revised to read,

"Performance qu?l if ication tests shall be conducted, supervised,

reported and certified by PDM and may be witnessed by on in- dependent testing agency approved by the Engineer".

NISTNCSTAR 1-1A, WTC Investigation 357
Appendix E

SK1LLING - HELLE - C H R I STI AN S EN - ROBERTSON

Page 5 September 23, 1968

5. Page 3, paragraph 7.2, Welders Certificntc shall be revised to state In the first line, "FDM will provide".

6. Page 3, paragraph 7.2.1, shall have an additional sentence added stating, "When a welder has not performed welding using a giver, process for 90 days, PJOfA or SHCR may require the welder to be

requalified for the process and welding positions in question".

7. Page 3, paragraph 9.1, second line should be revised to read,

"with approved 6hop drawings, Specification:: arid •-•elding pro- cedure"".

6. Pcgc ft

, paragraph 1C.3, uliould read. "pt*rioc of high wind unless welders and work are suitably protected".

9. Page 5, paragraph 12.4.2, first sentence, shall be revised to read, "Weld reinf orecnent as deposited will not be less than flush nor core than 1/8 inch, except th3t where applicable, the provisions of Appendixes E-l, E-2 and E-3, AWS Dl.0-66 shall apply".

10. Page 5, paragraph 12.6, starting in the third line should read,

"arcair gouging or grinding, and repaired and re-cxaieined aa prescribed by the applicable provisions of the Specifications,

approved PDM Quality Control Program and this walding procedure

specification (DB119-172, WPS-2. Thc6e defects discovered

through non-destructive testing technique after the defective

weld netal has been reooved and replaced".

11. Page 5, paragraph 13.1 starting in the second line after "UT" should read, "a mininum of ,100% of the first 10%".

12. P«age 6, paragraph 13.1.2, should road, "Ultrasonic Inspection

will be govciTicd by ?»m Quality C<j»iLj.oI iuuual, SccLiuu I-D-e, (revised 3-11-68) entitled "Ultrasonic Inspection, based on "Appendix U, Ultrasonic Examination of Welds (UT)", pages 14-20 inclusive, of the "Winter 1967 Addenda, ASHE Boiler and Pressure Vessel Codes, Section VIII, Unfired Pressure Vessels". The requirements of Section UA-903 of the ASHE Addenda shall apply to the work".

358 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKI LLIN6 - HELLE - C HRISTIANSEN - ROBERTSON

Pa?,e 6 September. 23, 1968

III Welding Procedure Specification, DB119-172, UPS-1

Through our review of procedures WPS-3 and WPS-2, we have the following additional cocwents on Procedure WPS-1 approved by SHCR letter of February 28, 1968, as well as PDM's revisions to page 5 ond page 6 dated 5-21-68 and superseding their previous revision

to page 5 dated 5-10-68:

1. Page 2, paragraph 4.1.1, fourth sub-paragraph (third from tcp

of page 2) should have o second sentence added 6tacinft,

"Electrodes which cere in ccr.ract with '-c tcr , grca=c :r dirt

2. Page 3, paragraph 9.1, second line should read, "vith approved

shop drawing. Spec i f lent Ions and welding procedure".

3. Page 4, paragraph 10.3, 6cccnd line 6hould read, "Periods of high-wind unices both welders and work are suitably protected".

4. P3ge *>, paragraph 12.6, should remain as stated in the February,

1S68 addition of WPS-1, with the following modifications:

a) paragraph 12.4.2 should read, "The depth and width of

weld deposit for each bead 6hall conform to Sections 405

and 406 and other specific provisions of AWS Dl.0-66 or

A'-'S D2.0-66, whichever is applicable".

b) it would be permissible to replace paragraph 12.4.3 in

the original document with paragraph 12.4.2 of the 5-21-68

revision, inasmuch as the initial submission by PDM represents a quality of work in excess of the requirements

of cither AWS D2. 0-66 or AWS Dl.0-66. Such pcnai6sion

should not be misconstrued to mean a relaxation in the requirements for good worlxsahship , byt rather a correction

of specific rules to confona to the welding codes included

in the Specifications. The first sentence of paragraph

12.4.2 in the 5-21-68 Revision should read, "Weld re- inforcement a6 deposited will not be less than flush nor more then 1/8 inch, except that where applicable, the

provisions of Appendixes E-l, E-2 and E-3, AWS Di.O -66

shall apply".

5. Page 5, paragraph 12.6, starting in the fourth line should read,

"prescribed by the applicable provisions of the Specifications,

the approved PDM Quality Control Program and this welding pro- cedure specification (DB119-172, WPS-1). Defects discovered

through non-destructive testing should be retested by the same non-destructive testing technique after removal and replacement

of the defective weld metal".

NISTNCSTAR 1-1A, WTC Investigation 359
Appendix E

SKILLIN6- H ELL E - C H R ISTI AN S E.N - ROBE RTS O N

Page 7 September 23, 1968

Page 5, porcf.roph 13.1, 5-21-68 revision, starting after

"in" in the second line should read, "a minimum cf 100% of the first 10%".

Page 6, paragraph 13.1.2 should read, " Ultrasonic Inspection

vill be governed by PDM Quality Control Manual, Section 1-D-e,

entitled "Ultrasonic Inspection" based on "Appendix V, Ultrasonic Focamlnat ion of Welds (UT)", pages 14-20 inclusive,

of the "Winter 1967 Addenda, ASME Boiler and Pressure Vessel

Code, Section VIII, Unfired Pressure Vessels". The require- ments of Section UA-903 of the ASHE Addenda shall apply to the work".

Cone irger.c upon Ir.ccrpcraticr. cf all the above cc=cr.ts into PDM Welding

Procedure Specifications DB119-172, WPS-1, WPS- 2 end H?5~3, SHCR approves

the text of these welding procedure specifications. It should be r.otcd that trany of the corameiila have been made to schievs clsrity cr eenforcity

to the contract docuoents and reflect the provisions of A'WS specifications,

canuf cc t urer ' s recotnaended practice, information contained in the; project

Specifications and similar related information, and are not intended as a change in the quality of work required under the contract.

Very truly yours,

SKILLINC, KELLE, CHRISTIANSEN, ROBERTSON*

^Jeoes White

JWrlm

cc: Mr. Lester Feld , PNYA

Mr K« •»* Fish* "^DM

F,S. Page 1, paragraph 4.0 Killer Metal and Flux. The following text should be added to paragraph 4.0: "The following welding materials

shall be used for welding steels listed under Section 2.0, either

together or in combination and for welding these steels to higher

strength steels Included in D3119-172, VPS-2 or WPS-3. Allowable

cnoisture content and exposure times 6tated in DB119-172, WPS-3 will

control whenever material included in thi6 specification is joined

to ASTK A514 steel."

360 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

4fe STAN RAY PACIFIC CORPORATION

subsidiary of STANRAY CORPORATION

11633 SOUTH >U>[0< S T • ( C 1 ICS HHCtlCS, OH'CKM » O O 0 t ' 5 6 6*2111

June 2, 1967

Mr. Lester Feld

The Port of New York Authority

111 Eighth Avenue at Fifteenth Street New York, New York

THE ftWT OF K£W VOW AUTHORITY RECEIVED

Ji^8 1967

WORLD TRAOE OEPARTMCMT WORLD TRADE CENTER

OmSJOK

Subject: World Trade Center

Contract No. WTC 217.00 Revised Quality Control Program

Dear Lester:

Enclosed you will find two copies of the Welding Procedures to be incorporated into our Quality Control Program which is outlined in section 105 of Contract No. WTC 217.00. This constitutes our entire

Quality Control and Testing Program.

The Inspection Requirements referred to as item 2 C in your letter

of May 25, is now completed and will be mailed to you on Monday, June 5.

Yours very truly,

STANRAY PACIFIC CORPORATION

F. E. Allen

Control ler

dh

Encl.

NIST NCSTAR 1-1A, WTC Investigation 361
Appendix E

SKILLIN6 - H EULE- C H R I ST I AN S EN - ROBERTSON

Co:iSLi?(>'tgSlniCJurc! and Civi/ tdsgiWcrs • 2J0 l\»fc Avenue, New Yptk, N. V. jOOJ? • Mu. OSSJi

John B. Skillin* • - Hclgs J, lidle • jchr.. V. Ch'r.stur.-.cn • Lvi/i'v' E. Robcrtmn

Cenn, September 13, 196S fiwoKl L. Wettftmstin

Joi<y>S F. /jf*>i,t

Pert of New -York Authority

Office of the Construction

Manager - Room 1119

30 Church Street

New York, New York 10007

Attention: Mr. R. M. Monti

Refprfnce: The '.-.'crld Tra.dc Ccr«tc^ Contract V.1C- 2 1 3 . 00 . Pittsburgh Des-Koines

Approval cf « elding Procedure Specification

She-its ar.d Procedure Qualification Tests

f :?n ti e;or.:

Attached hereto, please find a listing of all PDH Welding Procedure Sheets

and Welding Procedure Qualification Records submitted to SHCR for approval,

to date.

The date of approval by SHCR cf each procedure description or qualification

test is noted, as well as the description of the PDH correspondence to which

each approved procedure sheet was attached.

Very truly yours,

SKIUISC, HELLE, CHRISTIANSEN, ROBERTSON

Jac-.cs White

JW:Ja

etc

.

cc: Messrs. L. S. Feld, PKYA

H . M . Fish, POM

M. Tboaas, P'fi. bec: R. Gink, PN*YA », bec: L. E. Lit tie field, SHOP.

n © * t » r c. w t VI t v. *. »n>»*C »« -* «, « a Z c * » w i kI * M P. ~ * » C v«iri. <n,

362 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SHILLING - HELLE-CHRISTIANSEN - ROBERTSON

Kr. R. M, Monti. PKi'A -2- Septenbcr 13, 1966

SUMMARY OF PPM

WELDING PROCEDURE SPECIFICATION' SHEETS

AND

PROCEDURE QUALIFICATION SHEETS

?SM Joint Designation

MI-M3, N6-M8; S.\l

,

SA2. SA3: Fl-F?; 5?-

32, 60-11: 56-30; 58-

36, SS-42.; 60-35, 62-

80; 62-6

SHCR Approval

2/28/68

Rer.3rks

Accompany WTS-1 and VPS-1 Kcviaed February

1968.

K4, M5

62-EO (Rev) F6C , S5SA, S55B

3/13/68

4/ 9/6S

4/25/68

H60, S60

67-44, 67-48

S-Tl, F-Tl

F60A, M60A. S60A; 67-

45, 67-47, 67-65; 67-

73, 67-50A, 67-70A;

67-73A

S70; 62-8CA, 63-7;

67-50. 67-72, 67-72A;

67-76, 67-77

67-51, 67-69;

67-75, 67-75A

67-67, 67-66, 67-70

9/13/68

9/13/68

9/13/68

9/13/68

9/13/68

9/13/68

Accor.pany ?DM letter of 5/22/68. WPS-1 Rev. 5-21-68 (p. S & 6) & UPS-3,

May 1968

Accoopony Pun letter of 6/13/68.

PDM letter of 7/17/68.

Accompany TDM letter of 8/13/69.

Accompany PON letter of 8/19/68.

Accompany PDM letter of 8/23/68.

NISTNCSTAR 1-1 A, WTC Investigation 363
Appendix E

Office of Stic .Construe: ion Hnn.i£er 30 Church Street, Kew \'ovk City

October U,

PittKburch-Des 2S>ir.es Steal Ccsiparsy

Seville Island ?ictsbur«h, Pcsjasylvscia 15225

Attentions H.M. Fish

Reference: V.Q'.'XD X3£DS CHrrZK - Vn- C 213.00 - Inspection cr.u Schcdvlir.3

Contlc-cn;

This '.'ill cenfirr: r.y tclcsrc^: of October /,th -.."herein you vcrc c<i vised

that the Pitfccbursh Testing Laboratory of Pittibur^h, Pennsylvania

vxii oe providing ir.spccctcn tor enc 1'orc /.utnor lty on the above

rcfcrcr.ccti ccnLr.net. The inspection vill include siill inspection at your suppliers p lasts -is veil as fabrication inspection r.t your shop.

lcfcrcr.ee is r.-.eie to your Eeptonber 26, i

r.>67 letter rc^crtUnj nill

inspection procedures end your propoccd Tern for ccnvcyir.3 ir.foi—e- ticn on scheduling.

Pittsburgh Testing Laboratory will be advised to notify you 1—edlately

i£ any defective tsatericl is discovered in the ccursc of their T.ill inspection, so cc to enable you to teha the ncccccary action \;ifch your suppliers.

The instructions ycu propose to issue to your suppliers appear to cover our .inspection requirc^cntc .except that -if the nil! will furnish additional tost ssr.plcs for physical teste it ;rili not be necessary to require half a broken tensile specimen. F.T.L. can obVEir. their cw.

sample frea the physical sarsplc.

364 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

rittrbur^'.-.-Dcr Ko.ir.os Steel Cctapanj October 4, 1967

Vt-ur prc^c-cu fori: fov conveying ni 11 crdcr ettd £.-.br icncicn ivsfr/rsatien

r.5 requested by ?5r. Stiller e-f the Ticiirssr. r.cnlty avssl Construecloa

C«speny appears co contain all of the ir.forrjfiti.v. requested by Kr. Kr.JIcv. iDouevur, u-c *.:culi5 5U££CC! Chat it saisllt ba wove rcator.-blc to lict norc Essq one colvzzn on c.-.cl: cheer so as to reduce cSio toco.1 r.unl-cr of rhectr-. Such r. femot -..Tuld ccrvc es prclinir.^ry ir.fc— aticr. for the Authority

prior to your submission of a Ccritrtct Prcjvcsc Schedule zz provided

for cr. Pose 0=>03, Cleuse O.OOS cf the Ccr.trcct Specif ic.iticr.s.

Very truly yours,

$!,!:. Moeti

Cor.sc ruction ^-tJ.-.Rcr The U'orla Ircc'.c Center

bec :- Ercvr.. Cosinukc, 7i.\i, Robertson (SUCK) , Smith

NISTNCSTAR 1-1A, WTC Investigation 365
Appendix E

THE UORLD TRADE CENTER Page 3-0

CHAPTER THREE

FABRICATION OF STRUCTURAL STEEL

301 GENERAL

301.100 Structural steel shall be fabricated complete as shown in the

Drawings and in approved details shown in the shop drawings.

301.200 The steel furnished for each location shall have a minimum

yield point equal to that scheduled in the Drawings, and shall

be selected from the applicable steel specifications listed in

Chapter Two, MATERIALS.

301.300 All steel shall be ASTM A36 for locations where a specific

strength requirement is not stated in the Drawings.

302 IDENTIFICATION

302.1D0 The Contractor shall identify all steel which will be used in

the work beginning at the null and shall maintain identification

at all times thereafter including during fabrication. The method

used shall make both the grade and yield point of the steel

readily identifiable. Identification shall be maintained after

fabrication.

302.200 The Contractor shall identify each member or assembly with a system

The system of identification marks for fabricated structural steel

shall be approved by the Engineer

of marks. Each mark shall be clearly indicated in the shop drawings.

366 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Page 3-02 WE WORLD TRADE CENTER

303 SPECIFIC REQUIREMENTS

303.100 Flame cutcing by hand shall not be performed without the

Engineer's approval. Handcut surfaces shall be made smooth

by chipping, planing or grinding.

303.200 Fabricated material containing sharp kinks or bends shall be

rejected. Material straightened prior to fabrication shall

be carefully examined for signs of distress or other defects

before being placed in fabrication. Distressed or otherwise

defective material shall not be used in the work.

303.300 Where required by the Contract Documents, surfaces shall be

milled, or finished by other approved means. All finishing

shall be clearly shown in the shop drawings.

303.400 Bolt holes and similar holes shall be punched, drilled, subpuncned or sub-drilled and readied, and shall not be made or

enlarged by gas cutting.

303.500 Holes required by the Erector, and shown on the Drawings prior

to approval of Shop Drawings shall be furnished without cost.

NISTNCSTAR 1-1A. WTC Investigation 367
Appendix E

Issued 9/16/66 THE WELD TRADE CENTER Page 3-C

304 FABRICATION TOLERANCES

304.100 Fabrication tolerances shall conforn to the requirements of the

AISC Specification and AWS D1.0, as supplemented by specific

requirements contained in the Drawings and Specifications. In no

case shall tolerances exceed those obtainable by the best modern

shop practice.

305 SPECIAL REQUIREMENTS

305.100 Fabrication tolerances shall conform to the tolerances shown

on Sheets 3-04 through 3-17 inclusive. Where specific

tolerances are not shown on Sheets 3-04 through 3-17 tolerances shall conform to the requirements of the Specifications.

305.200 Cut edges of steel shall be free of burrs, overhangs, gross laminations, excessive slag inclusions and similar defects. Where necessary, cut edges shall be repaired be means described in the Contractor's quality control and testing

program. Where required to maintain weld quality, corners

of plates shall be eased and cut edges shall be ground. Work

of this nature shall be outlined in the Contractor's quality

control and testing program and shall be described in detail

in the Contractor's welding procedure specifications.

305.300 In certain locations in the Drawings, slotted or oversize

holes are specifically required. Where the Contractor elects

to use slotted oroversize holes not shown in the Drawings,

the use of slotted oroversize holes shall be subject to

the Engineers approval.

305.400 The Engineer will provide for the Contractor's use a table

of correction factors which the Contractor shall use to determine the correct as -fabricated dimensions of structural

steel members. The correction factor for columns will be

the sum of the correction for temperature at time of fabrication and the correction due to shortening under load. Correction factors will be based on a standard temperature

of 70 degrees Fahrenheit.

368 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

THE WORLD TRADE CENTER

Page 1-11

105 INSPECTION, QUALITY CONTROL AND TESTS

105.100 Quality Control and Tests

105.101 The Contractor shall comply with the quality ontrol

and testing program annexed hereto and forming a part

hereof during the course of the work to assure that

all work conforms to the Contract Documents.

105.102 The Contractor shall continually review his quality

control and testing program against experience gained

during the course of the work. Where the Contractor

desires revisions to his quality control and testing

program, he shall submit the proposed revisions to

the Engineer for approval. The Contractor shall not

make changes in the approved quality control and

testing program without the Engineer's approval.

The Contractor may, at his option, perform quality

control and testing in addition to that required

by the approved quality control and testing program.

105.103 The Contractor shall maintain complete records of

all quality control and testing performed by the

Contractor. Records shall be kept in report form,

and shall include the results of all visual control

of the work, the results of all tests and

NISTNCSTAR 1-1A, WTC Investigation 369
Appendix E

Page 1-12

measurements, and certification that equipment, materials and

methods conform to the Specifications or to procedure

specifications approved by the Engineer. The Contractor

shall state in writing his certification regarding the

completeness and authenticity of each quality control and

testing document. The Contractor's certification shall be

attested by the full written legible signature of the party in

responsible charge of the work for the Contractor and the

technician actually performing the work.

105.104 The Contractor shall submit mill test reports to the

Engineer for all material used in the work.

105.105 The Contractor shall report the location and quality of all

corrective work.

105.106 The Contractor snail furnish all testing machines, testing

machine operators and testing materials required for the

Contractor's quality control and testing program.

105.200 Inspection

105.201 Inspection is intended Co assure that the Contractor's

quality control and testing program maintains conformance to

the Contract Documents.

105.202 Inspection will consist of a random sampling oi the work

and will, to the degree possible, follow immediately thi

performance of the work. Inspection is intended, for the most

370 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

TEE WORLD TRADE CENTER Page 1-13

part, to consist of surveillance and evaluation of the

Contractor's quality control and testing program.

105.203 The Contractor shall furnish the Engineer free access to the

work. The Contractor shall cooperate with the Engineer to

allow Inspection.

105.204 The Contractor shall furnish, free of charge, all electrical

power, turning or moving of members, hoisting, staging and

other facilities required for Inspection. The Authority

will provide testing machines, testing machine operators and

testing materials used for Inspection.

105.205 The Contractor shall notify the Engineer a minimum of six

(6) working days in advance of the beginning of work subject

to Inspection. This requirement applies to each location

at which work is performed, and to each resumption of work

after any interruption or suspension of work. The

Contractor shall pay the actual cost of salaries and travel

expenses, in reasonable amounts, incurred because work is

not ready for Inspection at the time stated by the

Contractor

.

105.206 The Contractor shall not in any manner construe Inspection

to relieve the Contractor of any of his responsibilities

under the Contract.

NISTNCSTAR 1-1A, WTC Investigation 371
Appendix E

^-p= Pacittt; oar and Foundry Company

OO SOUTH HUDSON • iCATTLt, WASHINGTON 031 3-> • HO 2-7ja0

July G , 1967 PCF #666-14

THE PORT OF NEW YORK AUTHORITY

Room 300

111 Eighth Avenue

New York, New York

Attention: Mr. R. M. Monti

Construction Manager

Reference: World Trade Center

Contract WTC-214.00

Project D-666

Gentlemen

:

Please find enclosed two (2) copies of each of the following documents:

1. Quality Control Procedures - Revision 1, July 7th, 1967.

2. Welding Procedure - Revision 1, July 7th, 1967.

These procedures have been revised to suit your comments and those of

Messrs. Skilling, Helle, Christiansen, Robertson. In the welding,

procedure we have also included Appendix B, Welder Certification form, as requested in your letter of June 14, 1967. In the quality control

procedure we have added a section (part II, page five) which more fully

6Vrin.es the extent and methods of inspccLi»,n uhicii k- propose for this

contract.

We now request your formal -approval of these documents. A copy of this

letter and procedures has been forwarded directly to Mr. l>. Robertson

of Skilling, Helle, Christiansen, Robertson.

Yours very truly,

PACIFIC CAR AND FOUNDRY COMPANY

R. C. Symes, Project Engineer

Structural Steel Division

RCS/ap

cncl. rc : L, . Rooertson (SHCR)

J. Endler (Tishman)

J. Pigott

A. Philippy

D. Erickson

372 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKILLIN6-HELLE-CHRISTIANSEN - ROBERTSON

Counting Structural and Ct'Wi Engiiicfrs • 230 I'aik AxcihiC. New York. N. V. 10017 • Mu. 9~$S7<|

/o/iu B. Shilling Hc'.gc /. i/cl/e • Jo/m. V. C/iruiioiBCll - Les/ic E. KofwJiOli

July 13, 1967

Joseph F. /acitrm

Port of New York Authority

World Trade Canter I'lenninc 111 Eighth Avenue

York, New York 10011

AttcctJor.1 Mr. R. H. Honti, Conntructicn

Reforonce: The v'crld Trade Center Contract t.TC-214.00, Pacific C«r & Foundry

Cvallty Control and Testing Ptosrnm

Cenclcscni

Ve have reviewed the dccicrcntoj 1) Cu=lity Control Procci5ur«B, RcvioJou 1, July 7, 1967, and 2) Weidins Troccdurca. P-tvicicn 1, July 7, 1967, forvordo.U with th« PCF letter of July 8, 1967.

Eased urcm our roviev, we approve tho PCF Quality Control and Ttstirs ?rogrsn

contingent upon tho incorporation into the profrraa of the littached charts prepared by SliCR titled "Veld Inspection Ratco*' end uubject to tho r.pcclfic

conditions liotcd lierc-eftcr:

1. The void nurobera cud deni-jr-itlona used in the chnr'-s "Weld Inspection Ratca" (Sheet* Ko. 1-4 incluuivo attached borate)

in Ito current fcrta es of July 15, 1967.

2. The firot three full penetration oparjdrr.l butt v*ldB <l*«ld #10)

performed b7 cj\ch nev welding machine operator or voldor will bft subjected to ultrasonic testing.

3. Vberc a spandrol butt u«ld i»> rejected, oil weldn cade by the

«o=e voider or welding machine in the subject poucl, the pcncl

produced irosd lut cly provicuG Lo the cubjoct panul, noc Che

panel produced lemodiately nftor the subject panel, will bo tested by the ultrasonic tenting technique.

r . m, ». roiii"

»on»r c. livicn

v. *. t • AO • *

.

Rim m . *ocl*l

CKMIfl •*HDU1«* W ILLIAM o «*a*0

r , j . WHiTt,

t o r r , c I I . k O I « C . ftCATTLC. WASMINftTOM » « l O

NISTNCSTAR 1-1A, WTC Investigation 373
Appendix E

SKILLIN6-HELLE-CHRISTIANSEN - ROBERTSON

- 2 -

A. Approval of the TCP Quality Control onU Testing Trc^ratn docs net include approval of eny welding process or procedure subject

to AVS qualification toste (bcq Sheet KS-I1A), xnd docs r.ot include- approval of Drawings l.'S-HD end U5-UC.

3. Vioual ir.opecticn shall be carried oat by cortificd TC7 inepaction

personnel on 100X of oil types of voids Included in tho vorfc.

Very truly your*.

5niLLl!:0-GEU,E-CURXSTl«;SEK-B0?.KKXS0:;

Jar.c2 VTbite

cc: Kr. M. Levy

Hr, L. Fcld

Kr. W. CoolsuV.e

Kr. M. Springer

374 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

5KI1UHG HCUE

CHR!STlANStN BO8FRTS0N

Struttuiat & Civil fngiaetu

JTM contract: mc 2/4 o. :.W EX DZ/X/S ?ECVO>^. RATES

DATl r I.O ' to 7

mcpAHso or AfP»o»tD

V

X

r ° !

loo \ IS

5-

Weld FF> Skcch 4-AB2-V tinnyfi fAm*U

WVicn r<v\c o{ rttitcriorj

falls Vsclow 2%; ^/e o/"

inspeCTior; mty he r<cfoccd fo /2j'o'iols pet* 3 sftsry

panel of 66"^'%, —•

of equals, or exceeds ^%^msPcci-i9»\

rale sV// mcrc<\scd

-h /oo°/c unit! rejcci'tori

rMt -/or 5-Shcur^h'44'^

fedb. belew.

which -/-/nic inspcc-ii'ot

r^iit may a.aati^ be

reduced -hi

Intfcr.iCl /n irtscccr'icry ' i

j;*. ....

' - described abese ,

HKiirifl Perce^+o-oe <?f /?ej«c4-cd lA/elds for- Prezeedmcj

8 Hour Work 5hi-F+s 0c!5€c/ on A/«»wbcr of Wele$sTbte<

/Vo-Zc, Weld sKali CDtvfenn "fo -fta provisions o-f AWS DV.d-CbG,,

NISTNCSTAR 1-1A, WTC Investigation 375
Appendix E

SXIIUNG

H£l»* CHRISTIANSEN m X'o'NJR'A'C T yVTC 3 t od OATl . f.' /3.' (fi 7 Sh*«t No.

ROBERTSON

Stnjctuol i Civil En8; n*«'« \N£LD. »J$PE.CTJ6<\] ZATES - AFPROVSO o

V)

-*3

O

a

A>0

/4/?/5 Ac s .' We id // f/?# ev, /y ) IA/<? /</ FP} S hec-hc 4-A&2'p -thresh

r~ Begirt W/7/i lOo/0 /wjpccfi on r^Jc

35ft5

o

in spec /Von ra-f<i J/Vw* far

9-

1

TT 9

^ * \ i—i —i

1 1 •

1—

0.1 O.l 0.3 O.S 0,& I. o 8 to

Running f%ccc*\\&4C of rC€jec4cci VVg \c\ $ m Prcce.cdirt<ri

5 - 8 Hour- W^rfe Based /i/um&r af' Miffi-Te&jA

376 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Shod (Co. ROCMTSON

Srivclwfil - Civil Eas«iw*n

.

|* A?p»ovta

•v.

O

5

too

lo

o

^

ty - Cs-o ks<- - /3^/o uv/VJi loo°/o inspccFiot^ <t]ic , _Z „ Q ,

-h Shtc-f- M>. /,

i < (*D KSC - 6cj/n

T

6-

J

ids

• j.

c.i G,"*- 0.3 O.S 0,3 /.o /,£ 2 S /o

Running Rrcc^'Va^e o/' ^jec-fcd SWeMs /o Prccezdiyi*]

/Vfefc;

fc4 be ,*spcc+e.d -for t'6* /e^g4h

y<Zq inn >*nC} n-¥ Qhlumn es\ds ,

NISTNCSTAR 1-1A, WTC Investigation 377
Appendix E

KIIUNS

ritut CHfilSTlANSEN HOMR1S0N

Struc!ut*l & Civil tnginottrt

3-

0

v

loo

10

OA

Applies \r>\ WelcU ^2,3,4 FY <£>o ksc

Weld *// (h'lid mU o*ly ) lid r/eMs nol $pecificai/y

M increase a*id erUcrcosc of

'/izpccif on rotes similar -fo

»&--

T

3>

UJ/lh;

H—-+- o.l <?.S o.fc /.<> 8 /o

Puvu^i^Q Perce^a^e Keje<i+e<r/ Welds m P^eceeci'/r?q

5- S Hour Work Sh«T4s 8<3 sec/ £>/•? A

Afo-ki fVe/c/s /j2j3j<f be inspected -for l-o" fenylh

begihri/nq 4T Column ends, .

378 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

THE WHLD TRADE CENTER Pajc 1-01

CHAPTER THREE

FABRICATION OF STRUCTURAL STEEL

>1 GENERAL

301.100 Structural steel shall be fabricated complete as shown In the

Drawings and in approved details shown in the shop drawings.

301.200 The steel furnished for each location shall have a minimum

yield point equal to that scheduled in the Drawings, and shall

be selected from the applicable steel specifications listed in

Chapter Two, MATERIALS

.

301.300 All steel shall be ASTM A36 for locations where a specific

strength requirement is not stated in the Drawings.

Hie Contractor slmll identify all steel,

other than A.S.T.M. A36, which will be used in the

the work beginning at the mill and shall maintain identification

at all times thereafter including during fabrication. The method

used shall make both the grade and yield point of the steel

readiiy identifiable. Identification shall b.- maintained after

f jhr i < ;i t i< >n

.

302.200 The Contractor shall identify each member or assembly with a system

of marks. Each mark shall be clearly indicated in the shop drawings.

The system of identification marks for f»bricated structural steel

shall be a permanent system approved by

the Enuin't r. In .iddition, the Contractor* shall paint erection

302 IDENTIFICATION

NISTNCSTAR 1 1A, WTC Investigation 379
Appendix E

304 FABRICATION TOLERANCES

304.100 Fabrication tolerances shall conform to thf requirements of the

A1SC Specification and AWS D1.0, as supplemented by specific

requirements contained in the Drawings and Specifications. In no

case shall tolerances exceed those obtainable by the best modern

shop practice..

305 SPECIAL REQUIREMENTS

305.100 Cue edges of steel shall be free of burrs, overhangs, gross laminations, excessive slag inclusions and similar defects. Where necessary, cut edges shall be repaired by means

described in the Contractor's quality control and testing program. Where required to maintain weld quality, corners

of plates shall be eased and cut edges shall be ground. Work

of this nature shall be outlined in the Contractor's quality

control and testing program and shall be described in detail

in the Contractor's welding procedure specifications.

305.200 In certain locations in the Drawings, slotted or oversize

holes are specifically required. Where the Contractor elects

to use slotted or oversize holes not shown in the Drawings,

the use of slotted or oversize holes shall be subject to the Engineer's approval.

305.300 ^e Engineer will provide for the Detailer's use a table of correction factors which the Detailer will use to determine

the correct as-fabricated dimensions of columns. This correction

factor for column shortening under load is to be included in the dimensions shown on the Shop Drawings. A separate correction for temperature at time of fabrication is to be made by the Contractor

based on a standard temperature of 70 degrees Fahrenheit for steel

members

.

380 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

Page 4-01

CHAPTER FOUR

WELDING OF STRUCTURAL STEEL

401 GENERAL REQUIREMENTS

401.100 Welding of structural steel shall conform to the requirement

of the AISC Specification and AWS Dl.O, except where the AISC

Specification or AWS D1.0 is specifically modified or supplemented

by information included in the Drawings or Specifications.

402 QUALIFICATION AND CERTIFICATION OF WELDERS

402.100 Welders and welding operators shall have passed the applicable A

qualification tests prescribed in AWS Dl.O, Appendix D, Parts II

and III. AWS qualification tests shall be supervised and witnessed

by an agency approved by the Engineer. The approved agency shall

issue certified test reports which describe the tests performed

and indicate the results of the tests. Certification papers

issued by the approved agency shall clearly state the types of

work the welder or welding operator is qualified to perform.

Certification shall be achieved immediately preceding the date

the subject welder begins work under the Contract. AWS

qualification tests and certification shall be paid for by

The Authority and witnessed by the Engineer's Representative.

403 WELDING PROCEDURE SPECIFICATIONS AND JOINT QUALIFICATIONS

403.100 Joints conforming to the details specified in AWS Dl.O, Article^

209, 210, 211, 212, 213 and 214 and welded in accordance with the

NIST NCSTAR 1-1A. WTC Investigation 381
Appendix E

THE WORLD TRADE CENTER Pa g« *-03

405.200 Welding electrodes and flux for submerged arc velding shall

conform to Section 202, MATERIALS.

405.300 Gas snetal-arc welding materials, where approved for use in the

work, shall conform to Section 202, MATERIALS, and to the

requirements of the approved welding procedure specification.

382 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

WORLD TRADE CENTER

Page 1-13

105 INSPECTION, QUALITY CONTROL AND TESTS

105.100 Quality Control and Tests

105.101 The Contractor shall comply with the quality control and testing

program of Montague-Betts Company, Inc., dated June 9, 1967, as

such program is revised in the respects indicated in the letter

from Skilling-Helle-Christiansen-Robertson dated June 23, 1967,

to the extent necessary to obtain the approval of the Engineer.

The aforesaid program and letter are annexed hereto and form a

part hereof.

105.102 The Contractor shall continually review his quality control and

testing program against experience gained during the course of the

work. Where the Contractor desires revisions to his quality

control and testing program, he shall submit the proposed revisions

to the Engineer for approval. Hie Contractor shall not make

changes in the approved quality control and testing program without the Engineer's approval. The Contractor may, at his option,

perform quality control and testing in addition to that required

by the approved quality control and testing program.

105.103 The Contractor shall maintain complete records of all quality

control and testing performed by the Contractor. Records shall

be kept in report form, and shall include the results of all

visual control of the work, the results of all tests and

NISTNCSTAR 1-1 A, WTC Investigation 383
Appendix E

WOHLl TRADE CENTER < ogfc

part, to consist of surveillance and evaluation of the

Contractor's Quality control and testing program.

105.203 The Contractor shall furnish the Engineer free access to the

work. The Contractor shall cooperate vith the Engineer to

allow Inspection.

105.204 The Contractor shall furnish, free of charge, all electrical

power, turning or moving of members, hoisting, staging and

other facilities required for Inspection. The Authority

will provide testing machines, testing machine operators and

testing materials used for Inspection.

105.205 The Contractor shall notify the Engineer a minimum of six

(6) working days in advance of the beginning of work subject

to inspection. This requirement applies to each location

at which work is performed, and to each resumption of work

after any interruption or suspension of work. The

Contractor shall pay the actual cost of salaries and travel

expenses, in reasonable amounts, incurred because work is

not ready for Inspection at the time stated by the

Contractor.

105.206 The Contractor shall not in any manner construe Inspection

to relieve the Contractor of any of his responsibilities

under the Contract.

384 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

QUALITY CONTROL PROGRAM

THE WORLD TRADE CENTER CONTRACT WTC-226.00

FABRICATED STEEL ROLLED CORE COLUMNS, INTERIOR COLUMNS

LOUVER WALL STRUTS AND ROLLED BEAMS NORTH & SOUTH TOWERS

THE PORT OF NEW YORK AUTHORITY NEW YORK, NEW YORK

SUBMITTED BY MONTAGUE- BETTS COMPANY, INC. JUNE 9, 1967

NISTNCSTAR 1-1A, WTC Investigation 385
Appendix E

RECEIVING (under the direct supervision of Yard Foreman)

a. Materials will he checked as unloaded for conformance with mill order and

shipping papers.

b. Materials will be stacked on blocks off of the ground in predetermined storage

areas

.

c. Bay numbers will be recorded for future reference in locating materials as needed.

d. Remarking size, length and grade will be done as necessary.

e. Each piece or bundle will be marked with the letters PONYA.

f. Discrepancies in quantity, length or grade will be reported immediately for

replacement

.

PREPARATION (under the direct supervision of Yard Foreman)

a. Cutting to size will be by sawing, shearing or machine flame burning.

New pieces will be marked to maintain proper identity.

C. lumn ends will be milled as required and protected against normal weathering

with a mixture of one part white lead, one part linseed oil and two parts lard.

FABRICATION (under the direct supervision of Shop Foreman)

a. Layout and fitting will be performed by Fitters working with necessary Helper(s).

b. Detail parts will be tack welded for location.

c. Holes will be punched, drilled or subpunched and reamed.-

d. Copes, blocks, notches, etc., will be accomplished by hand burning and grinding

smooth

.

e. Overhangs, gross laminations, excessive slag inclusions and similar defects

will be corrected by grinding or Arcair gouging and built up as necessary with

weld metal.

f. Material will be cleaned of oil, grease, dirt and foreign matter only.

g. Pieces will be marked as shown on shop drawings using DuPont 065-3010 white

mecal primer on a background of Tnemec #99 red metal primer; marks will be

between 3" to A" high and background 4" larger than complete mark.

6-9-67

386 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 6

SKI LLI NG — HELLE - C H RISTIAN SEN - ROBERTSON

Consulting Structural and Civil Engineers • 230 Park Avenue, New York, N. Y. 10017 • Mu. 9-887^

John B. Skilling • Helge J. Helle • John. V. Christiansen • Leslie E. Robertson

Consultants June 23, 1967 Harold L.Worthington

}oseph F. fackmn

Mr. Lester S. Feld Port of New York Authority

World Trade Center Planning

111 Eighth Avenue

New York, New York 10011

Reference: The World Trade Center Contract WTC-226.00, Montague-Betts

Quality Control Program

Dear Lester:

We have reviewed the Quality Control Program submitted by Montague-Betts

and have the following comments:

1. Receiving

Material received should be checked against the certified mill

test reports for size, grade, heat number and color code. One copy of each certified mill test report should be submitted

to PNYA and to SHCR. Where applicable, mill test reports should

be marked to indicate non-conforming material and the disposition

of same. Where possible, off heat material should be described,

in writing, prior to receipt of certified mill reports.

2. Fabrication

Overhangs, gross laminations, excessive slag inclusions and similar defects should be defined and repair procedures for these defects should be outlined. The location and quality of all repairs should be reported.

3. Welding

Certification papers for each welder and welding machine operator

should be submitted to PNYA and to SHCR. These papers should include all positions and processes to which each welder will be assigned.

WAVNe A. MtW»

r. «. A . foster

FRANK HOELTldHD"' ROBERT C L.BVIKH

V. A. PRIIADIKT KENT ft. ROfllOl

CHAftlCB SANDUSKY WILLIAM O. «ABB

E . J. WttfTC, JR. LOBCMT8 L. WIOING IKATTLI B f V I C I I 1S40 WASHINGTON ft U I I. D I N G . SKAT TT. C. WASHINGTON SSIOT

NISTNCSTAR 1-1A, WTC Investigation 387
Appendix E

SKILLING - HELLE-CHRISTIANSEN - ROBERTSON

Welding procedure specifications must be prepared and qualification

tests performed by the fabricator, where applicable. One copy of each welding procedure specification and report of qualification

tests should be forwarded to PNYA and to SHCR for approval.

Preheat and interpass temperatures must conform to the welding

procedure specification where specific preheat and interpass

temperature requirements are included in the welding procedure

specification.

All welds should receive 100 percent visual inspection.

Non-destructive testing of welds has not been described, and may

be divided into three classes:

The quality control program should describe the amount of welding

to be tested, and the techniques to be used, such as dye penetrant,

magnetic particle or ultrasonic. All testing of welds should be

documented in inspection reports, one copy of each report to be forwarded to PNYA and to SHCR.

A. Inspection

The amount of periodic inspection of work in progress and the persons performing this inspection should be described.

The inspection of finished work should be documented in reports, with

one copy of each report to be submitted to PNYA and to SHCR.

Very truly yours,

SK1LLING-HELLE-CHRISTIANSEN-ROBERTSON

- 2

1. Fillet welds

2. Partial penetration welds

3. Full penetration welds

James White

JW:e

cc: Mr. H. Weinstein

Mr. W. Cosinuke

388 NIST NCSTAR 1-1A, WTC Investigation
Appendix F

Supporting Documents for Chapter 7

This appendix contains the supporting documents that are referenced in Chapter 7 of this report. All of

the documents contained in this report are reproduced with permission of The Port Authority of

New York and New Jersey. Table F—1 contains a summary of supporting documents and their location

within this appendix. The footnote numbers given in the table correspond to those in Chapter 7.

Table F-1. Supporting documents for Chapter 7. Footnote Number Document Title Page(s)

Section 7.1 - Overview

1 General instructions from Malcolm P. Levy of PONYA to prime contractors for WTC

contracts (WTCI-239-P)

390

Section 7.2 - Erection Marks and Marking System

General instructions on erection marks and marking system for structural steel from the

Port Authority to steel fabricators suppliers for WTC 1 and WTC 2 (WTCI-495-L)

395

Section 7.3 — Quality Control and Inspection Program

3 Memo dated July 26. 1968 from David L. Brown of PONYA to James White of SHCR

(WTCI-515-L)

400

NISTNCSTAR 1-1 A, WTC Investigation 389
Appendix F

THE PORT Of NEW YORK AUTHORITY

111 Eighth Avenve-« 15th Slrctt. New York. N.Y. 10011

World Trade Department

CuyF. Torioli, o»m«

tithird C Sullivan, Dincw. TTk Trxj< Center

Mllcclm P. levy, CW. fljnowit * Co"oTMo«M> DH-n.c« TrlrphoiK Cm U0-S2JJ

GENERAL INSTRUCTIONS TO CONTRACTOR FOR WORLD TRADE CENTER CONTRACTS

To Prime Contractors

The following information Is directed to your attention la order that you may

acquaint yourself with the procedure the Port Authority desires to follow upon

execution of the contract

.

After execution of the contract, you are requested to direct communications

as follows:

Sublect Matter Addressee Copies

All correspondence pertaining

to administration of contract other than that specifically

required below to be directed elsewhere. This includes

correspondence on contract

changes, natters pertaining

to field problems, including

changes Eteszaiag from field

conditions, job progress and schedule.

To: Mr. J. Eadler,

Assistant Vice-Free.,

Tisbman Realty &

Construction Co. , Inc. 11th Floor, 30 Church

Street, New York, K.Y. 10007

Submit original and one copy to Mr. Eadler

and two copies., to Mr. Honti

All correspondence pertaining

to administration of contract which involves additional

expenditures or credits,

requests for approval of subcontractors, and notification for off•Elte3 inspection

of materials and equipment, etc.

To: Mr. R.M. Monti,

Construction Manager, Room 1119, The Port

of New York Authority,

30 Church Street,

New York, N.Y. 10007

Submit original and two copies to Mr. Monti and one

copy to Mr. Endler.

390 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

Subject Hatter

'Ojop drawings and catalog cuts.

Approval of equipment and material including samples,

purchase orders, lists of materials and equipment pro- posed to be furnished under

the contract and proposals

for substitutions for specified material or equipment.

Insurance Hatters

A report of all accidents

arising in connection with

the work trust be Bade to the Port Authority.

Addressee

To: Mr. Marvin Airman,

Architectural Coor.,

Tishman Realty & Con- struction Co., Inc. 11th Floor, 30 Church Street, New York,

N.Y. 10007

To: Mr. Honti

To: Mr. Charles P. Levinson, Insurance

Manager, Room 1005 The Port of Hew York

Authority, 111 Eighth

Avenue, New York, N.Y. 10011

To: Mr. W.F. Gillespie,

Claims Attorney, Room

1163, The Port of New

York Authority, 111 Eighth Avenue, Mew

York, N.Y. 10011

Copies

.For information on number of copies of

shop drawings, size required, etc., see Contract Specification

clause entitled, "Working Drawings and Catalog

Cuts." Submit original

drawings to Mr. Altman,

one copy of each

transmittal letter to Mr. Monti, and one copy

to Mr. H.A. Tessler,

Manager, Project Planning. Room 300, The Port of Hew York Authority, ill Eighth Avenue, New York,

N.Y., 10011.

Direct original copy of all correspondence

to Mr. Monti, one copy

to Mr. Tessler, and one

copy to Mr. Endler. For further instructions on inspection of material

see clauses of specifications entitled "Inspections and Rejections"

and "Workmanship and Materials".

Direct original to Mr. Levinson, with

copies to Mr. Monti, and Mr. Endler.

Direct original to Mr. Gillespie with

copies to Mr. Monti

and Mr. Endler.

NISTNCSTAR 1-1A, WTC Investigation 391
Appendix F

THt PORT Of NiWYO« AUJHO*'TTT

-Please note the following requirements:

1. Under the clause of the contract entitled "Inspections and Rejections", you

are required .to. furnish lists of material and equipment furnished under the contract. Such lists of material and equipment to be installed under the contractor must bear the vendor's name, manufacturer's name, trade name, Btyle

designation, catalog number and any other information necessary to completely'

identify the item.

All lists of materials and equipment must be submitted within ninety days

from receipt of letter of acceptance of contract.

Requests for changes in materials and equipment from those specifically

mentioned in the contract specifications must be submitted within a minimum

of forty-five days of the approved date the contractor's schedule specifies

as the time for implementation for the particular item.

A. All. correspondence, shop drawings, purchase orders, samples, catalog cuts,

etc., must bear the Port Authority contract number and be referenced to specification section.

5. All correspondence must come to the Port Authority or Tishman Realty & Construction Co. Inc., through you as the prime contractor. Correspondence

submitted directly to the Port Authority or Tishman by subcontractors or

materialmen will be given no consideration.

£. Request for approval of material and equipment will cot be honored and no ins^ction made until the subcontractor placing orders for such material

or equipment has been approved.

7. Yeu are requested to prepare a list of the shop drawings, catalog cuts and

samples which will be submitted for approval as required by the specifications.

This list should be sent by you to Mr. Altman, with copies to Mr. Monti and

Mr. Tessler with dates indicating when you will submit the items for approval. The

dates' which you establish on this list should be those which you feel necessary

in order to meet the required completion date for all work under the contract.

It is requested that this list be submitted within forty-five days of receipt

of this letter.

Also a list of items which will be inspected at source will be developed

Jointly within ninety days of the date of this letter.

8. In order that work under the contract may proceed expeditiously, it is urgent that you submit the names of your subcontractors for approval without delay. Forms requesting approval of subcontractors must include the following information:

A. Name and address of subcontractor.

B. The amount of the subcontract, including the analysis of the subcontractor's bid on forms furnished by the Port Authority. Ho approval

of the subcontractor will be Issued without the analysis of subcontractor's bid.

392 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

TM£ PORT Of ~J W YORK AUIMOmlT

- 4

C . An accurate description of the vork- involved.

D. Three references on work of similar nature previously perforced

'by subcontractor.

Malcolm P. Levy, Chief

Planning & Construction Division

The Vorld Trade Center

NISTNCSTAR 1-1A, WTC Investigation 393
Appendix F

ttoveobe* 7* 196?

::r. iicrncn Wloscr*

Proler Structural Ctaok w.» *nc.

V'ovnoa Ulvu.

Uiin la land City, i!«v York 11106

Bat TUa World Trade Center • Contract WTC-2U.00 •

Sbop Drawing Procedure* and Marking Sygteu

Dear ttr* Wlntorii

Enclosed for your mfarofltloa And woo «ra letters and

procedures previously SfioC to oilier fabricator* on fcl>« HTC Tovare.

T.\oao proccwuroa wro £«velop«d Joist ly Kasteu 8ridga Retailers

sterling 1» April 1967.

Sincerely*

Looter S. Fold

Planning Enamour

Ebcleewres:

1. Srcctlon narits end aorklng eye tea for structural otoel

1q tho U7C Towers - Pfl£«8 1 • 10 Inclusive tinted 10/1/67

2. Letter of Juno lb, 1967 on Erector's Derrick Elviaieo

3. Crcwio£& S-VJt-lLOO and 8-iUWOOO «Uitcd 5/25/67

A. Indea to Harks Cyetoa • dated 10/15/6? (2 pa^ea)

cci i^oore. J. J^Olsr (TBCC), J. White. (BllCft) - w/eocl. tfl

bect Hoaere. 9. Brown, R. Co^de, M. Levy, R. Monti, H. Teaeler

394 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

ERECT10S MARXS AND MARKTNC

SYSTEM FOR STRUCTURAL STEEL Rev. 4/28/67 THE WORLD TRADE CENTER

NORTH AND SOUTH TOWERS

1. Each nark shall bo painted in accordance with the Specif lea cl oof Id tho same position on each piece. as the mark appear* on Che ereccico dravlng. All marke shall.be followed by tho. Erector's Derrick Dlvlalen, Sea Item 20 below.

2. • Exterior Wall Columns (Bolov the lac Story Splice)

Ceo Che column nuober shown on the dealgn drawing

• affixed with che column tier number. Examples:

(a) 301 < s5"sl> . indicates - Col. 301 from

Tier SS (El. 242) Co splica above Tier SI

(El. 294').

(t>) • 330

(SX* 1J

- Indicates . Col. 330 (On ceneerllce of Tower) from splice la Tier SI to splica

above first floor.

Tier curks ara in accordance with Archiceei designation wherein:

S - Service Level - El. 294' 51 - Sub-Level 1 - El. 284* 52 - Sub-Level 2 - El. 274'

53 - Sub-Level 3 - El. 264'

54 • Sub-Laval 4 - El. 253'

55 • Sub-Level 5 - El. 242'

3. Exterior Wall Columns - (Above 1*C Story Splice)

Use che column nuober shown on cho design drawing Suffixed with the column tier; Examples:

(a) 330 - Indicate* - Column 330 (on eoncorllna of Tower ) from che lec Story Splice co tho splice above the 4th floor -hat is from

El. 318' to EX. 363'.

(b) ; 030 - Indicates - Panel 330 (On ccntcrllno of Tower) from che 4th Story Splice (El. 363')

to the 9th Story Splice (El. 41B.96). Hote chls is • "Column Troe Panel" co bo fabricated by P.D.M.

Stool Co. and the panel mark used is the Diddle

column number of tha chree columns comprising cha column creo.

NISTNCSTAR 1-1A, WTC Investigation 395
Appendix F

(c) 200 1 *

V)

- Indicates- Panel 200 - A corner pAacl «t t?.£. Corner of Tower from the 16th Story Splieo to the 20th Story Splice. Thie is a corner

column spandrel panel to be fabricated by PC&T, end here Ogata the panel amber used 1* the middle

column number of the three columns comprising the column tree.

•»» Core Columns

Use tho column number shown on the design drawing auff1* vith the column tier number. Examples:

(S&-S2) S01 * - Indicates - Corner core colusa

S01 froat Tier S5 '(El. 242) up to the eplico above tier S2 (El. 274').

(S2>1) 60S - Indicate* - Core column 605 froa spiled in Tier S2 (El. 274') up to splice la - 1st story.

605 . — Indies toe -Core colusa 605 free

1st story splice to 3rd story splice.

5. Interior Columns (Below the 1st floor - El. 310')

Use tho column cumber shown on the design drawing suffixed vith the column tier number.

(a) 1200 <s5*s3>. indicates - Column 1200 froa

Tier SS (El. 242) up to splice in Tier S3 (El. 264)

.

(h)

(c)

6. louver Wall Struts

Use tho letter S followed by the column line number for

the exterior well column suffixed with the floor number. Example:

(a) S302 *7 "9* - Indicates - Strut on column lino 302 extending from the 7th floor to Che 9ch floor.

7. Vortical Bracing at Exterior Halls

Use the letters XE followed by numerals 1, 2, etc. Example:

(a) XB1 » Indicates - Exterior Well Brace 1

(b) XB2 - Indicates - Exterior Wall Brace 2

396 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

- 3

Pleaso note chat do tier aarks are used as a suffix here, harks shell appear oo elevations of election drawing*

only. - not in plana.

£. Vertical Bracing at Core Columns

Use che letters CB followed by nuoerals 1, 2, tec. Example:

(a) CB1 - .Indicates . Core Brace #1

0>) CB10 - Indicates • Core Srace DIQ

Please coto that no tier marks are used a* a suffix here. Marks shall appear on elevations or erection drawings

only.* not in plans.

9. Interior Pipe Posts, Hangers. Etc.

Use tho lecccr P followed by numeral 1, 2, 3 etc. and suffix with the rior stark. Exeaple;

(a) PI ^7 * B^ - Indicates - Poet ouaber 1 extending froa the 7ch floor to the 8th floor.

0>) PI *41~*2X . Indicates - Post number 1 extending froa the Alat to the 42nd floor.

10, Floor BeamsUse a njcorel euff ixed with the floor number. All beams within tho core shall he consistently marked all the way

up che tower. That is a beam fraising between cere coluami 501

and 502 alghc be narkod "1" on each floor of che tower, such

•st

<s) 1 ^ - iDdicatos - Beam 1 - At floor S3 (El. '264').

<b) 1 - Iodiccte» - Beam I - At floor 10

(c) 1 . Indicates - Beam 1 exactly

alike from 11 through 20 floors. This will aid

the erector to locaca a beam which may bo used on

floors 11 through 20 a c assumed location baewcen

columns 501 and 502. All beams outs id s tho core

which are of a ropocltious nocuro such as framing

at the 7 and 9, 41 and 43, 75 and 77 and 10B and

110 shall also be consistently narked In numerics.!

sequence.

NISTNCSTAR 1-1A, WTC Investigation 397
Appendix F

- k -

11. Horizontal Bracing at Exterior Hall - At Beam Framed Floors

All diagonals and tsruta within the 10' -3" panel area

adjacent to the extorter column reference lino shall bo prefixed

with the lotter 11 followed by • numeral and suffixed with the fleer designation. Example:

HI < 7> . Hi <9)

, RIO H10 {*.3} would ell

be horizontal braces lo Tower - > ©touring *t the 7, 9, 41 and

43rd floora.

12.- Prefabricated Floor Unite

All prefabricated panels shall be prefixed "T* followed by a numeral and suffixed with the floor designation. All panel*

to be numbered clockwise starting with "1" at the panel between

core columns SOI end 502. Example

:

(a> . Fl C10>

, F2 ( I0>, etc. • Indicate? floor unit at 10th floor.

(b) -Fl (15i

, F2 * 15)

, r ctc. - indicates floor aaie at 15th floor.

With regard to components comprising prefabricated unite,

the following ground ruice shall prevail:

A. All trusses, bridging, bracing and beams for prefabricated floor units supplied by laclcde

to the assembler (Koch) shall be narked ad agreed between the parties. Laclede shall furnish an assembly diogram to Koch showing components lo each "T" panel.

B. All steel deck and power/ telephone cells for

' prefabricated floor units supplied by Cranco

to the Assembler (Koch) shall bo markod as agreed between the parties. Grace o shall furnish an aaacmbly diagram to Koch showing components of deck and P/T cells in each "F" panel.

C. The assembler (Koch) shall furnish a combined assembly diagram showing all components comprising

each "F" panel.

13. Loose Deck and Loose Power/Tolcphono Cells for Beam-Framed Arena

and Core Areas

All loose deck shall bo prefixed SD followed. by a numeral

end floor designation such as:

SD1 {7)

, SD2 <7), etc.

Similarly ell power/ telephone calls) shall be prefixed PT

followed" by « numeral and floor designation such at:

FTl (9), PT2 C9\ ete.

398 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

- S -

14. Archer Bar* ond Anchor Platce (aeo drawing SAB-15S)

Use prefix VX ac exterior walls.

Use prefix VC at perimeter ot core.

Ixeaples: WX1, KX2, etc. • Indicate - Anchors ae exterior wall

•KCl, WC2, etc. - Indicate'. Anchor* AC core perlinocor.

Noco - No tier designations are roquiroil. All anchor* will

bo ah own and located on erection plant and field welding ekecchoa.

15. Shear Scuds

Prefix "R" - followed by 3 digit numeral indicating

diaaeter in eighth*, length in inches end eighth* such as:

R7A2 - Stud - 7/6" diamotor x AV'long,

shell he painted on all keg* or container*.

16. Papping UnltB

U»e Prefix "D"' -

Example: Dl, 22, 1)3, occ.

NOTE; No tlor designation* are required

16A. Krlllagea. Base Placet and Anchor Bolta

Uae the following prefix letters:

C - Assembled Grillages

BP - Loose Base Plate*

AB - Anchor Bolte

All the above prefix letters ere to be proceeded by the Tower letter thus:

A-Cl. A-G-2 , etc. (Tower A Grillages)

B-Cl, B-G2, etc. (Tower B Grillegea)

A-BP-1, A-BP-2, etc. (Tower A Baoe Plates)

B-AB-1, t-AB-2, etc. (Tower B Anchor Bolte)

NISTNCSTAR 1-1A, WTC Investigation 399
Appendix F

MEMORANDUM

to: James t/hite - Ski I Hng-Hel le-Chrisc iansen-Robertson

from: Oavld L. Brown

date: July 20. 1968

;uoJE;C T THE WORLD TRADE 'J ENTER - CONTRACT VJTC-2 30.00 - QUALITY CONTROL j. SAFETY

PROGRAM

RtF E RENCE

copy io- L,S- Feld (W/Att), R.M. Monti. F.H. tfemeke; A. Guttentng (TRCC)

Please review the attached Koch Quality

Control Program as soon as possible and let me

have your comments on same.

DLB/ DUD

ACt.

avid L. Broun Supervising Engineer

The World Trade Cencer

400 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

April 25. 1968

Outline of Items to hf Included in Qu.il Jty Cont rcl Prog

Erecting Corepnny

A. Survey Control

1. Methods ar.d Equipment

2. Qualification of survey personnel

3- Establ ishnenl of monuments and reference lines

B. Coiilrv/1 of Construction and Erection Loads

1. Loads on work, platforas and finished structure

a. Weight of equipment

b. Weight of stored materials

c. Posting of load limitations

d. Provision of planking where required

2. Cranes and derricks

a. Boon angle vs. weight of pick

3. Bracing and erection sequences

a. Column bracing in Plaza area

b. Bracing of core columns for tower cranes

(1) Sequence of jumping bracing

(2) Sequence rf jumping crane

(3) General erection sequences

C. Field Welding

1. Control of field veld details vs. Fy of material

.

2. Qual i f irat ion and certification of welders

3. Qualification and certification of welding procedure specifications

for joints not pre-qual i f i ed by AWS .

NISTNCSTAR 1-1A, WTC Investigation 401
Appendix F

4. Preparation of welding procedure sdocI f ir at lr>n<= f»»r v?-!d£ sr.d Jd:;t

designs designated pre-qunl I f led by AWS.

5. Control of preheat and InnerpnnB t eiuperai urcs

.

6. Control of welding electrolier., wsjidaCBfe fluxes, v;Cidi«7r s hi e Irl i ng

gflscs, and the like.

7. Stoiage of welding mater talc such as heating ovens for low hydrogen

elect rodes

.

D. Bolting of Structural Steel

1. Control of type of bolts and washers used

2. Installation methods and procedures for bolted connections

3. Quality control and assurance that high tensile bolts are properly

tightened.

6. Control of ASTM A307 bolts

5. Control cf set-up of bolted Joints

6. Cleaning of faying surfaces for bolted joints

E. Control of Stud Welding Operations

C. Erection procedures

1. Plumbing

2. Fit-up

3. Cuylng and bracing

It. Elimination of ~i~ftfr Z. ' Z'3

1

er from box columns and similar members.

Allowance for temperature chiingps and related movements and

deflections of structure.

402 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 7

-i - - - - — - ~ - - r

1. Klnne-cut t ing

2. Rfamir.g of holes

3. Drifting

I. Control of Erection Tolerances;

1. Refer to tolerance diagrums Included in the Specifications.

2. Surveying and other controls.

J. As-Built Drawings

1. Preparation of as-built drawings, procedures for.

2. Control and maintenance of as-built drawings and related procedures.

K. Safety Programs

1. Hoisting equipment

7. Guying materials.

3. Wind conditions

4 . Provisions for bad weather

Note: KK£ should relate their quality control program carefully to the

provisions and requirements oT the Specif icalions and Drawings.

Possibly in some areas of the KXE quality control program,

explanatory sketches should be prepared and included in. the document.

NISTNCSTAR 1-1A, WTC Investigation 403
Appendix F

This page intentionally left blank.

404 NISTNCSTAR 1-1A, WTC Investigation
Appendix G

Supporting Documents for Chapter 8

This appendix contains the supporting documents that are referenced in Chapter 8 of this report. All of

the documents contained in this appendix are reproduced with permission of The Port Authority of

New York and New Jersey. Table G-l contains a summary of supporting documents and their location

within this appendix. The footnote numbers given in the table correspond to those in Chapter 8.

Table G-1. Supporting documents for Chapter 8. Footnote Number Document Title Page(s)

Section 8.2 - Variances Relating to Fabrication/Erection Tolerances

1 Letter dated December 27, 1967 from Richard Chauner of SHCR to Robert Dempsey of

United States Testing Company (WTCI-499-L)

407

2 Letter dated December 22. 1967 from James White of SHCR to R. Monti of PONYA

(WTCI-499-L)

412

3 Letter dated June 20, 1969 from James White of SHCR to R. Bay from Laclede Steel Company (WTCI-506-L)

415

4 Letter dated November 1 7, 1969 from James McGuiness of SHCR to R. Monti of

PONYA (WTCI-506-L)

418

5 Letter dated October 16. 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

424

6 Letter dated October 20. 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

426

7 Letter dated June 16. 1969 from Malcolm Levy of PONYA to Carl Weber of Laclede

Steel Company (WTCI-506-L)

429

Section 8.3 — Variances Relating to Defective Components

8 Letter dated June 20. 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

434

9 Letter dated December 15,1 969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

437

10 Letter dated July 7, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

440

1 1 Letter dated July 3, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

442

12 Letter dated March 3 1

, 1 969 from James White of SHCR to R. Monti of PONYA

(WTCI-506-L)

445

13 Letter dated June 6, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-736-L)

449

14 Letter dated May 19, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-736-L)

458

15 Letter dated May 5, 1969 from R. Monti of PONYA to H. Fish of PDM (WTCI-735-L) 462

NISTNCSTAR 1-1A, WTC Investigation 405
Appendix G

Footnote Number Document Title Page(s)

16 Letter dated March 20, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-738-L)

463

17 Letter dated June 6, 1969 from James White of SHCR to R. Monti of PONYA

(WTC1-736-L)

464

18 Letter dated May 16, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-735-L)

469

19 Letter dated June 9, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-736-L)

474

20 Letter dated May 16, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-735-L)

477

21 Letter dated May 16, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-735-L)

478

22 Letter dated July 15, 1971 from James White of SHCR to R. Monti of PONYA

(WTCI-736-L)

481 !

23 Letter dated August 21, 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-740-L)

484

24 Letter dated October 7, 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-738-L)

485

25 Letter dated October IS. 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-739-L)

489

Section 8.4 - Variances Relating to Alternate Fabrication/Erection Procedures

26 Letter dated September 21, 1969 from R. Monti of PONYA to W. Gibson of Stanray

Pacific Corporation (WTCI-490-L)

491

27 Letter dated October 16, 1969 from R. Monti of PONYA to Robert Bay of Laclede

Steel Company (WTCI-506-L)

493

28 Letter dated December 15, 1967 from James White of SHCR to R. Monti of PONYA

(WTCI-748-L)

497

29 Letter dated May 26, 1969 from James White of SHCR to R. Monti of PONYA

(WTC1-756-L)

498

Section 8.5 - Variances Relating to Product Substitutions

30 Letter dated May 2, 1969 from James White of SHCR to R. Monti of PONYA

(WTCI-756-L)

500

31 Letter dated June 1 1, 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-739-L)

504

32 Letter dated December 18, 1967 from R. Monti of PONYA to H. Fish of PDM

(WTCI-745-L)

505

33 Letter dated December 18, 1967 from R. Monti of PONYA to H. Fish of PDM

(WTCI-745-L)

510

Section 8.6 - Variances Relating to Inspection Practice 34 Letter dated May 3, 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-742-L)

515

35 Letter dated April 18, 1968 from James White of SHCR to R. Monti of PONYA

(WTCI-483-L)

517

406 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

PROJECT MEMORANDUM

FROM: SXILLING-HELLS-CHR1STIANSEN-ROBERTSOK

J.S40 Washington Building

Seattle, Washington 98101

DATE: Dccerber 27, 1967

TO: United States Teet-ng Company

5521 Telegraph Road

Lob Angeles, California 90022

ATT'N: Robert Deapaey

SUBJECT ;The World Trace Center- New Yor's Contract V.'TC 217.00 Stanray Pacific Steel Inspection

RE: Transnltted to you on 12-21-67 *?s a ccoy of a telecrao from

Jao?es White, SHCS-^ew York concerning diner, el oral tolerances

en -."-c box eoluens. Included with this telegram v,as Stanray'

s

interoffice mcir.orar.duni showing th-Jr I rterpret v*i or.s of this

telerri>.3. The foli.ov.ing co.tr.ents are to be alied to these

e ketches

.

O This applies only to clip angles on the flange

and we'O plates.

(2) These miniirum ed?e distances apply only away free

the end of th £ coluir.n. Tolerances at the end shall

ba 1& Inchest 5/' 2 inch.

{^J A1 5 C »elu shall ue ifiCrstxesu Lj "vl'ie Kau d inrnslcn

.

In addition to the above, other iter.s were trar.s netted verbally.

1. The detail of welding certain clip ar.rles en\l for

;'lllet welds on thrse sides leaving the heel 0. the

•s.r.gie free for beac clearance. The .VKS Code re- quires a return of the fillet weld on this side.

This is not required... -

2. Variance of the er.d tolerance on colucr. 604-5 has

been.approved by the s ^oervl 3I ng engineer. This

perir.itts one flar.&e to be offset 3/l6 *.r.ch lr. place

of 1/S Inch as specified on Pare 5-04 of tie contract

cocunent.

NISTNCSTAR 1-1A, WTC Investigation 407
Appendix G

PROJECT MEMORANDUM Pe£e 2

FROM: SXILLING-HELLE-CHRISTIANSEN-ROBERTSON

1640 Washington Building

Seattle, Washington 98101

DATE: December 27, 1967

TO:

ATT 'Ki

SUBJECT:

RE:

J. All hold d i^eiisl or.a on the detail dravln-s shall te

£• l/lo Inch except aa ^rJilfled by the enclosed

telejrraa.

4, Slotted holes 8'iall not be hand flame cut.

5. The tolerance on the dimension "between flanfces

of t'ne colinin shall be plus 1/8 inch ar.d minus

1/k inch.

Very truly yours,

SKI LLI^S -H ELLE-CH*! ST TAX SEK-RC HERTS

SHCR-Ncw Yor'<c Jim Vhlte

408 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

k

W M*i«»(W toy «h* w, r. maaikau

CT\m*»«M o* t*% ***** TELEGRAM

TW Mm «v»t tt—» jiklulMi Jo—Mit nhrmni U lOCAlTWt .t pui «T »>;•. Tut*' sfftulet • tOCAl TlxI u tm^i W imam,

1'13?4 P£T DEC 20 6? U1C2

SS01S? L NADJ2 RX POB N£V YORK NY 20 14$P EST

J N-TAAKAN, STANRAY PACIFIC CORP.

11*^53 SOUTH ALAMEDA ST LOSA

THESE RULINGS APPLY TO BOX COLUMNS FABRICATED UNDER CONTRACT

VTC-2 17.00. ITEM ONE REFER TO DRAWING 6-ABl-iM 6-AB?-2. ANGLE

" IRON CLIPS THESE AND EQUIVALENT DETAILS MA 7 HAVE ELONGATED

HOLES. LONG 0IMEMSI0N PERPENDICULAR TO COL W.N FACE SHALL BE

BOLT DIAMETER PLUS l/U INCH, SHORT DIMENSION STANDARD 1/16

INCH OVERSIZE. THIS PROVIDES 1/8 INCH PLUS OR MINUS TOLERANCE

'FROM KEEP DIMENSION TOLERANCE FOR ROUND HOLES SHALL BE 1/16

INCH PLUS OR MINUS KEEP DIMENSION.* ITEM TWO NO WEB PLATE IN

COMPLETED MEMBERS SHALL MEASURE LESS THAN ONE INCH FROM FACE

OF.VEB TO INSIDE CORNER OF FLANGE PLATE. 'THIS ALLOWS WEB PLATE

TO RUN STRAIGHT END TO END OF COLUMN AND ACCOMMODATED MAXIMUM

.-..ALLOWED SWEEP OF 3/S INCH IN THE FLANGE PLATE. ITEM THREE FOR

TXil U I I.H BAHll WESTERN UNION

unmillrMinM A «W irf i-» V«> AY A*Vi r>lv>ul

KL-Nii>u Linn

IT —J

Tit um uc»t * i£- n U- •* docftru* 1 i'm r *au U LOCAL TIN* it polfti ci c« j A, Tko* «f rral»t U hOCM TIME it pcunr •( Jnut.itt L NAO92/2

COLUMNS FABRICATED ON OR BEFORE DECEMBER 16 1?67 WHEN INSPTECTED

AT -MILLED ENS5»-l/io InCH Gap AV ROOT OF "LONGITUDINAL FILLET

WELD' PLUS 1/52 INCH*F0R OUT OF SQUARE CUT WILL BE ALLOWED UHEN

MEASURED AT INSIDE PLATE. ANY GAP EXCEEDING THIS ALLOWANCE • SHALL RECEIVE AlSC MINIMUM FILLET WELOS BEGINNING ONE INCH

FROM THE MILLED COLUMN END AND PROVIDE FULL THROAT MINIMUM

OF NINE INCHES IN LENGTH

JAMES WHITE.

WTC-21?.00 6-AB1-41 6-AB7-2 1/4 l/)6l/&/? 16 '9*7 V?2

1.

NIST NCSTAR 1-1A, WTC Investigation 409
Appendix G

STANRAY PACIFIC CORPORATION

INTER- OFFICE [MEMORANDUM.

fromt .lot TVJ-K'*'^

Deui 1*2. • it - H 6*J

5wbj.cn U)0/U-D TTladS. Ce.«OTE>/£

IC&Xfi SH.A.LiC n>c cow PLtreD *oi 7 «,/j r^e Limit;* op

'

Of .<LoL is

Rouvorv Role

OR.

f)

"1

• a\ ^ ?r

410 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

STANRAY PACIFIC CORPORATION

INTER- OFFICE .MEMORANDUM

To,

frerru

D1J.T.

. ii K-H* \

Oot«i

4-

T7

h*. » D O \. C

Ttj-e. Gap /£<t mksle. or

: column shall ^07

U£L» Site. AT <^P 4MALU*P*£.

l>0 CAE. ACE1D ' ACCSftlX/JfirLY'

shall, be I£k\)0S.£D

C^AfiS AT THE fc'Qfr OF Coy.*.

S»U-ALL °-C ' M^X. Ai

If CAP IV MOltt TVAK) T«^£ LiMiT**

fur ^'ue>J<i flUCf ~ - '- £ Mf iaj •* i u & op C^tuwu tTAiVp^ a^YOAJO MILLS J) .

1 1

V

MA*

I/*'

Mt»x,

I 1/ «~

NISTNCSTAR 1-1A, WTC Investigation 411
Appendix G

SKI LLIN© - HELLE-C H RISTIAN SEN - ROBERTSON

ConiuItinsStmetunl andCm! Entfnesn • 230 Part Avenue, New York, N. Y. 10017 • Mu.9SS7H

John 5. SWfoif • Hcfe* /. Hfifo - JeJsn. V. Chriitisnwij • Utffr E. Rcbertfon December 22, 1S67 CewwJunu

- fe**A F, Jtdktaa Port of Hew York Authority

Office of che Construction

Manager - Room 1119

30 Church Street Hew York; Km York 10007

Attentions Mr. R. n. Monti, Construction Manager

Rtfereace: The World Trade Conter Contract WTC-215.00, Moohc

I'olerancen for Sox 3uai

CcaElement. Kudosed please find a copy of a letter roceivad by SHCR free Masher Stool

Ceepacy dated December 14, 1967 requesting approval of tolerances shown on

the 8-1/2" x U" sketch prepared by Mother and attached to their letter.

We approve the tolerances as shown on the Kosher sketch. ' All tolerance

.

figures ehova are 1/16 or 1/6 inch (sea sketch).

We approve a naxlaua twist in box coluans s» fabricated- of 1/A. inch whe r aessured at .one end is relationship to the other' endVary truly you**,

SK22AING-atU& • ^miSTlrUiSEN-SOBERTSON

JW:s

ce: Mr. U. C. Bradford, Mosher Mr. U Fold, PNYA Mr. R. Fonech, SIS Mr. J. Clulo,: SHCa-SE

Enclosure'

W.THI *o iii.ii

P. »• *• fft*T« ft rmjLM* i<ft<kT»itor* »o»»»» t. ktrilM

Xltkln. 0. «»»»»

«. 4, kmri. d».

412 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

mr

111! !lSill STE E L COM PANY

ENGINEERS- FABRICATORS - KRECTOR6

,,,, «,'•<> '•• !>'• HOUSTON. TEXAS 77001

Decesbcr l1*, 19^7

SkiUlng - Hello - Christians aa - Robert sea

230 Pari Avenue

Hew Yori, New Yorh 10017

Attention: h^r. Janes White

Befcreace: Sie World Irade Center Contract WTC - 215.00 MoBbor

S. 0. 31060 & 31061

Centlesea:

Fabricatica toleraccea on set forth. In Specifications 30^.100 and 305. 100

ara dear as far as "built-up columns are concerned, however they are not eleer as far as built-up hex "beans are concerned. We do oat feel that it . was ever intended for the "box be one, which are considerably lighter than

the hox colums, to he fabricated according to tolerances shown on sheet 3-0t which pertains to box coluane.

Oiercfore, wo ore submitting for approval our sketch which Indicates the

fabrication tolerances which we re cocaand in the fabrication of box beans.

We have already started burning the flange and web plates for the box beass

and would appreciate your giving this natter your earliest possible consideration.

Also, ve have not received as yet -written confirmation for a rfrfirrifln one must** Ef nn inih twist in tho iVari cation cx the box colunns.

Yours very truly,

KOSHER STEEL COMPANY

W. G. Bradford

Works Manager

cc: BZU

cc: Vox

ruu*n Mi imu omen MOVllOU • BA1LA1 • TTlU LUtkOCK WfvtTQH COIIMl tHUitt • Wt ANTONIO

tAIU O/nCil f NtW TOM - lOI ANUlU

NISTNCSTAR 1-1A, WTC Investigation 413
Appendix G

r

IT m -jy

.'^ 'ST ,3 I

DETAILING DIMENSIONS

-is

+ /6

c—

t/j' At f*£>£

So.

UJL

DfPm MOTH AND OUT-OF-SQUAQE

TOLERANCES

fBEAMS)

414 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKILLIN6, HELLE, CHRISTIANSEN. ROBERTSON

Cotaukiuz S/h,i.*..m? cnrfCnd p.nsiwcn 2-n fVrfc Awnuc, N«r York, N. Y 10027 • Mri. <)-$S7i

)oIm J). $ki!li»s '• Helgtj.lklk jclinV Chniliunscn • Lcs'ir E Robertson

Manage

Wavur A Divmr

Comulftfii'f June 20, 196V ,

. „ . T

Laclede Steel Company

Arcade Suilding

St. Louis, Missouri 63101

Attention: Mr. R. Bay

Reference: The Vovli Trade Center

Contract WTC-221.00, Laclede

Approval of C32T33, C32"i'34 and C32T35 trusses

CentlcEen

:

Jn corf inEatioa of our telephone conversation today, Mr. Jackson of PTL

has been instructed that he can waive the 4V' Hold Exact dimension on

8 - C32T33

8 - C32T34

A - C32T35

provided the dimension is Ln oo case less than A inches (Laclede Drawings

£T23J, 5T23A and ST/235). Mr. Jackson has alEo been requested to inform

the writer inaeJiately by telephone of any recurrence of the above problem

on new production of the three affected truss designations.

This approval is granted on the basis of SUCR review of clearances at truss seats and your uisc^ssicr. with KKE in vhich KK7. Ji^reed to accept

the subject twenty (20) trasses from Laclede for fabrication, provided

Laclede would rectify all difficulties, if any, experienced by KKE due

to Laclede's deviation from the approved "Hold Exact" dimension.

Very tr^ly yours,

SKILLIKG , HELLE, CHRISTIANSEN, ROBERTSON

*

r

•

L . S. Feld, PKYA * -o«t.. «««

R. Piasecki, KKE «>u'». a. LO O .OH

A. Cuttmtag, TRCC L«»Y»i»«'"»,7wis»»e .ic-*»t>i.»«»*.e»

NISTNCSTAR 1-1 A, WTC Investigation

415
Appendix G

# l/orm /Zus*r>r March 13, 1965

Mr. Wayne Brewer

Skil ling-He 1 le-Hri stiansen- Robertson

230 Park Avenue

New York, New York

Dear Wayne:

Request for Acceptance of

32" Trusses not Fabricated

According tc Approved Drawing

The purpose of this letter is to formally request approval

of the twenty (20) trusses listed below that were verbally

approved by Mr, Gene Chorny at our Madison Plant on March

11, 1*69.

4 - C32T35

8 - C32T34

8 - C32T33

These trusses were fabricated with the "hold cxect" dimension at the core end as being 4" instead of 4-1/2** as shown

on the approved drawings. t , Gene and 1 feel that this may cause a tight fit when the

panel is placed in the building but the panel is adjustable

enough to accntrmodate this variance.

Yours very truly,

LACLEDE STEEL COMPANY

Thomas M. Chura , P. E. Research Engineer

Construction Products

lp

416 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

NISTNCSTAR 1-1A, WTC Investigation

AM
Appendix G

SKILLING. HELLE, CHRISTIANSEN. ROBERTSON

Consulting Si'ucturcJ and Cm! Fngmi'crj • 2 ill Pari .\»vnu*. Sew Vori. N V J'X)/" • Mu '>-VS"4

Kovesibor 17. 1969

Pile WTC-J2iC-WTC-223C

< .in .tljiX,

fort of «tu Tort Autbcrlty

vHtico of cac KniimctioB Manager

30 Courci Street -lotb floor

fccw Tcri. Kev Tork ICQ?

fttrpctlcn: Mr. E. H. Hoot!

Bof ercacs

:

T3xs World Tre<ie Ccntct Contract tTC-221.00, Ucleoe

Coctrsct vTC-223.00, £XE (Ortemt)

Toicraocos st:>J Repair rrcc&Ooiea Lott«r of «o*<;«sb«r 7. 1563. £k£ to TSCC

•we fc-vo reriavtuj tr>o UUS letter or floveaiber 7. 1969, re?3rJiog :c ],r-cc«, «ad repair procures ca C32TC truaee.*. Our cccss&sta folic-*. attach a* <>.cs *b*. t M . i -isevisj tbc retired toleraccea ceriScre io <jueatiec. Wo - for the centre Id sueutiec. Wo approve of Tolerance Schedule 5 on KKE Dxr; . TW («t«b«J to OS . Jioveaba, 7. i965 l«tet) as tbo «Mi=ffl allovabl* tolcr*r,co 9 cd/ov o&J CP ^05.

Eepolx UC attd 15C ot> KXX DwC». TOD art T6C reo^extivoi v. «rc n Pn rovc<

88 aoterf (»« attaefcafiota). mi* repair uori t, to be ioQC at ^ coot t0 ?vfA );, cLi mscs yhj.ro the tcleranco* 6h<r^n or- SEC? aheet tu>, 1 are wooded.

SklU.I>:C. UELLe . CbHl STlANSLi P.r?ER7Sr?.

Ja=*s T . ."xCulnnesR

J7X;<Jf

R. Lay, Liclcaie

S. FLasccti. K!0: ;°*'V ', \\\\\ A. Cuttcatas. TTCC I**" T'lV"".

0.'

e * m - • t s /• »**om u so*

418 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

NIST NCSTAR 1-1A, WTC Investigation 419
Appendix G

-j CHI

fler/>j/z, P/zr; /5C~ usei? qj^ai vsfirtc/it—

' stazt weep.

/torfov cnotip

s& A-A

7<*C

420 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

r

L.

!>hu

II u

I Struct yjCtp

Pa

Sec T. C-C

Si~c7- & '-Ps

NISTNCSTAR 1-1A, WTC Investigation 421
Appendix G

Tislvran Itaalty and Construction Co., Inc.

30 Church Street

Mew York, lieu Yorh

Attcntion: Mr, Al Guttentas

Project Ilar.as^i" Ko; Letters from K, flasechi to A. Guttentas

dated April 11, 1969 end July C, 19C9

Dear Sirs:

As stated in the chovc refc-roricod letters the assembly of truss

Beat details 13C and 15C on ,r G" type panels is ctill unresolved

and a cause of irritation for all parties concemsd, L-aclede i3

continuing to fabricate C32TG trusses at tolerances that discallov

placenent of the above truss scats in a plxrvb position end accurate

location!. As a result rar.y "C" panels on floors 10 through 51,

Tower A, have shewed, canted and uIg located truss coats despite our efforts. These disurspaacies cause numerous field problems

as well as criticism frcn inspection pcrsorsisl.

Kindly relcr tu the enclosed sl'-etches ; drawing TGA chows the

tolerances we use in the placeraent of tmss; seats. Dravrin^ T62

shows throe tolerance schedules that ray be used in locating ver- tical struts on the C32T6 truss. Tolerance schedule A now used by

]-acledc obviously allows large deviations in the plurbness and

location of the two vertical struts. V.'e find that in rany cases

trvs;. seaLt* 1I>C cad I3C sir .ply cannot be placed at the proper

longitudinal spacing due to physical interference srith the struts.

Vherc they do not interfere,, the struts aTe usually out of plirab

necessitating extra weld and ratcrial to tnhe up the cap between

tii? truss scat awd the 5tr«t.

Tolerance schedule B is the required tolerance to set truss seats

exactly as shown on Laclede drawings CL-205 and CD209 without

incurring any c::tra uorh. In addition the truss scats sxnald

cutor.aticall;- be in their proper locations when fit up flush

against the vertical struts.

Tolei-ancc schedule C could be used by Laclede to insure that no

422 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

r^ffftfrrTTPn , r^ karl koch erecting co., inc.

? 'iJ^Z'-^OO HOOSCVEV.T AVC CARTtntT, N- J 07O0B • 201/ Be* 1700 - C.,^tu IERECTING

o» v o <a>9C CtkltM »"»OJtCT

- 2 -

strut Interferes with the placement of truss scats; However the

consistent use of n previously approved repair detail, referenced on the drawing, would bo necessary* Cf the three tolerance schedule!)

this seer'SVtost realistic for achieving accurate placement of truso

seats. Ve surest tint trusc.es be fabricated to these tolerances

and the approved repair detail be nsdc a scheduled detail, included

in shop drawings, whenever caps between the strut end the truss scat

exceed 3/16 inch. All extra costs cust be for the account of "othere 1 '

rruycutl> Uc have C4 = C32TG ' trusses in yard storage all of which

exceed tolerance schedule C. The asscrjbly of "G" panels has been

halted starting with the 52nd floor. Of the 66 trusses Laclede has

agreed that 20 tresses require rejrjjvsl of the vertical cCrut on the

exterior eclum end and 32 require rer-oval of the strut on the core end according to their o-.-ra. criteria. Vc arc therefore submitting,

for approval, repair dotail.s-15C and 13C on drawings TGC and 76D

for these cases. Laclede has agreed to pay for the repair or only

those trusses cccceedinj their c\m tolerances.

In crfcr to resume csserJbly of "G" panels va urge a clarification

of all tolerances end their consequences for 17TC 221. CO and 223.00 os well as an approval for the enclosed repair details.

cc: U. Monti, EOTYA L. Feld, KiYA

D, Ucptint», Laclede

J, iicGuinuess » SuCJl

end.

FJ>:h3

Yours truly,

rArx koch ejecting co IMC.

Richard Piasechd

Project Engineer

NISTNCSTAR 1-1A, WTC Investigation 423
Appendix G

SKlLLtNG, HELLE, CHRISTIANSEN, ROBERTSON

Consulting Stjvctuut' Jnrf Civil E«£iiiccis • 2>0 JVk Avenue, New York, N. V. J0027 • Mu. °~SS7-I

|t>hn C. Sfci'i/i'iJf • Jlffgc J. Mc/ic • Jo/in V, C/in'iliunjoi • Lcsfi> K. Robertson

Jlfiineftr VS'orp;* A BffWti'

October 16, 1569 F f^fac* Flic: WTC-221C

Port of New York Authority

Office of thi CcTisiructic-rt f!iria£ci 30 Church Street

New York, Kev York 10007

Attention: nr. K. «. fiemti

Reference: The World Trade Center Cootract WTC-221.00, Laclede

Fabrication Tolerance

Gentlemen:

Please refer to Laclede's letter to SRCR dated September 18, 1969. A xerox

copy of the Laclede letter is attached hereto for your convenience.

V'e spprovc s tsleroCicc for height above top chord of end stif fevers V3 and

V4 of 3n

(+ l^S" >-3/8").

Very truly yours,

SKXLLING, HELLE, CHRISTIANSEN, ROBERTSON

cc: Mr. L. Fcld, FNYA

nr. w. Borland. PNYA

Mr. R. Bay, Laclede

Mr. B. B. Jackson, PTL-St. Louis LER KAB JTH LCJ

e-.tacliment

* * * i a. * © o s • » *x»»Vt« »- liHDVtK* Will UM & . W* »fc

» C * T r L I D » / J C * , > * * > wAfHiMOTcH t |,f t 1 C 1 K tit' % ft t * T T fc. »• t * » I i« , h M D 'i » » I O I

424 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Mr. Wayne Brewer

Skilling-Helle-Christlsnaen-Robertson

230 Park Avenue

flew York, New York 1C017

Dear Mr. Brewer:

This letter is written to request a change in the tolerance for

Hhg b-sightb. above the top chord of the end stiffeners (V2 snd

V4) that *re fabricated in the ends of the trusses supplied to

» t. •» - * * ~~— _ > - fc — »

This dimension is not critical and our fabrication process

would be greatly augmented if it were changed from 3" +1/8"

to 3" +1/8" -3/8".

Yours very truly,

LACLEDE STEEL CO>f ANY

RobeVt D . Bey

Director of

Technical Services

Proiect Coordinator

IP

NISTNCSTAR 1-1A, WTC Investigation 425
Appendix G

SKI LL INS. HELLE. CHRISTIANS t'N, ROBERTSON

Conju/ijn^ Sfrocfi/rti/ and Chi! Engineers • 2*0 Paik Awttuc, New York, N. Y. 10017 • Mu. 9-SS7-J

}ohn S Skittmg ilclgc ]. HcUc • }ohn V. Chiktiamcr. Leilic E. Robertson

Wayne A. Dmm

lUidti I. Wtuthmiton October 20 Jowp* F. Jactson File: WIC-221.0O

Port of New York Authority

Office of the Construction Manager

30 Church Street New York, Ne« York

Attention: Mr. R. R, Monti

Reference: The World Trade Center Contract VTC-221.00, Laclede

Fabrication tolerances

Ceotleoen:

Please refer to the Laclede Steel Cospsny to SBCR dated October 6, 1969.

A copy of the subject letter is attached to this letter for your reference.

We approve the tolerance of i3/8" for the 2-7/8" cr 1-3/4" dissension at the top chord Intersection of the inclined strut (aark 2 in tbe shop drawings)

as requested in the Laclede letter. Please note that this tolerence applies

to inclined end struts on 24T crashes only. This relaxation of tolerance

csncct be allowed to extend to other cases. One example is the vertical strut ceober ST {ste=bers 2 and 5) for truss C32T6 on Laclede sheet number 5T206. it is essential that these sersbers be installed as accurately as possible in all cases.

Very truly youia,

SKILLING, HELLE, CHRISTIANSEN, ROBERTSON

Jaaes White

cc: Messrs. L. Feld , PNYA

W. Borland, PNYA

R. Bay, Laclede

B. Hckson, PTL @ St, Louis

.-.*.»»«»«< >«•«•»• -«•

426 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

$ J*»itj. //,±±rr.ti f,3/C/ October 6,

Mr. Wayne Brewer

Skilling-Kelle-Christiansen-Robertsor

230 Park Avenue

Vc.'k , Srrfc Turk iOCi 7

Dear Wayne

,

This letter Is v/ritten to reouest a tolerance of - 3/8" for the

eii menslon of 2-7 /A" or 1-3/a " r>"!2t locate- the upper end cf the

Inclined strut fMar-v- 5 1 i ~ h j c fabricated i r. cr.c cr bcth cr.de of the following 2b" trusses.

2UT9 2U Til

2itTllA

?4T10 24T113

2&T10A 2^T11C

2iiT103 24T12

c - 1 i jC

24T10D 2^ti3a

2UT13C

C-T13D

2«T10H BT216A

BT216B

3T?r?C

3ecaus2 of the larp? nunoer of these trusses that we plan to

fabricate In the very near future, a pr-vnpt reply "vould be rreatly

ap^rec i ated

.

Years very truly,

LACLEDE STEEL COMPANY

RtoSfert D- Bay

Director of Technical Service;

o~-n < t Cccr-i'^atcr

y-6o

NISTNCSTAR 1-1A, WTC Investigation 421
Appendix G

428 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

THE PORT OF NEW YORK AUTHOK1 TV

•Vurld Tfdjv Depjii mcni

Cu> f t»w/ni< D--f.i..(

R.irtj-ri (. s vlt.*j-» n .... . i * i »v i ' ..i* •

J-j=s it, 1965

Laclede Steel Coapany

Arcada Building

St. Leu 1 , Hissourt 63101

Attenciont Mr. A. Carl Veber

fte; Iba World Trade Center - Contract MIC- 221. 00 - Field Valded Connections fcr Bridging Trusses

and Bridging ingles »t Panel Joint*

Geotlescn:

A. After oa«tr»lnj actual oc-elte difficulties encountered

Lo Tcver "A" (dua to alaeiignaa-nt and accumulation of fabrication

tolerances) In field -reldlcg tbe referenced connection*, we directed

the Erector to procead follcve In order to expedite the work:

1. Use single butt plate, field voided option,

thaw co DrivingI 7C/1, 8C/1, 9C/1, IOC/1 and

11C/1 vole t occur a total of S6 tlaea on a typical

floor. Butt plat* thickness was determined by

KKJB frae- fiald mtis^zsstzzz si tszv&l gaps zz

the ends of bridging trusses in "•» erected"

position.

2. At connection 2C (which occur* I2C cImi on a typical floor) and coonactloa 19C (which occurs

4 tleci on » typical floor) all field velclcg

eta s eliminated by adding 4 eitrt #5 bare parallel

to eacb rov of bridging angles. Eatra eteal for

a typical quadrant la eboaro on Driving FT* 1 CSevlaed 6-9-69).

3. At connr-tiona 7C thru 11C two extra #3 bars ere added at all bridging truce panel jotDte to compensate (or horizontal veld acroea top of top

chord eaglets which vae elljnlnatid because of ttgbt

welding clearnocea.

illovtr:-; 101 for lsp i , ? .£ tor.t of a:r> reinforcing

is presently being addad for floors 10-20+ per floor.

NISTNCSTAR 1-1A, WTC Investigation 429
Appendix G

Laclede Steel Coapacy - 2 - Juno 16. 1969

5, Connection* 13C thru 17C restain *• origiaaily designed

with ao change la field welding detail* occurring • total of 20 tl»»» on • typical floor.

B. To oltlsiate co»r», Lacleda la dlr^scasd to proceed at follow* ©a all future dellverices

I . *t conn»cHP« It • deist* coautctloo plate, mark

P-l. *• shown on Laclede Drawing Ct-201.

2. At connect ion 7C - delate connection plates, mark

T-2 and ?-3, aod delate connection bar. caerk CB-l,

•11 shown on Laclede Drawing CP-201

.

3. At connection BC - delete tccjoectlcn plate, stark f-*, delete connection bare, nwrk CB-1, and

on Laclede Drawing CE-2J2.

it. At connection <K - da] eta connection plates, Mark

T~7 and l»-7, and delate connection bar, airk CD-I

,

all shown on Laclede Drawing CS-203.

5. At connection IPC - delete two connection bara, stark CJ1-2, abovn on Laclede Drawing CP- 202.

6. At connection 11C - delete connection plate, mark

t-2 aod delete connection bar, mark CB-1, all ehown on Laclede Erawing CD-JCX».

?„ At connection* }3C thru 17C • Ko change

B . At crnn^tton l^C - delete cotmection plate, mark

*-6, shown on Laclede Braving CI>-20*».

9. Hold clear dletance of 1" alalaw», froae center of

panel joint Co edge of web struts at both chorde

do aa to pertelt the ule of either f laid welded option

in itea A or field bolted option propoaed In itetB C below.

C. Laclede la to aubttlt separate unit pTtcc quotations on eacb ot tbe following bolted alternatea on a per floor baali:

1. Conntct^cn 2C - furnish, fabricate and ship 3/4"

thick pistes <?y»50) and »hl» stock (Fy-36) ebown

on Drawing 2-C/2 - revlaed 6-13-69. Note X - all

3/4" plataa to be shop welded to bridging anglaa by

Laclede. Thle connection occurs 120 timet per typical

floor.

430 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Laclede Steel Company - 3 - June 16, 1969

2. Cinorctjoo 7C - funlih, fabricate end *hlp 3/4"

thtck places <ry-SO) aod whim atock (fy»36) ahewo

on Drawing 7-C/J . ravie*d 6-13-69. gate T . mil

3/4" plate* to be shop welded to bridging true*

chord angle a by Laclede. Tbl* coonectioo occura

52 tiaaa per typical flcor.

3. Connection 8C - furalah, fabricate aod abip 3/4"

Chick piataa (Fy"50) and ahtc stock (?7~3t) shtrtm on Drawing 8-C/2 - revlaed 6-13-69. See Hot a ~Y above. Thli connect loo occur* 12 tlac-a per typical

flocT.

4. Connectlqn 9C - furolab, fabricaCc and ehip 3/41 thick pletee (fy»J0) and iMa atock (fy-36) abewa

on "rawing 9-C/2 - revlaed 6-13-69. tec Sote T above.

Thla connection occur* 8 tlsea par typical floor.

5. Connection IOC - furnish, fabricate aod ahlp S/v5 thick plate* (Fy-50) »nd ahlaa atock <ry-36) shown

oo Drawing 10-C/2 - Tevlaed 6-13-69. Sea Wot* Y

above. Tbt* connection occura 12 lUci per typical

floor,

6. Cccnwcticm DC - furniab, fabricate jod ahlp 3/4"

thick plate* (jy-50) arid ahlai atock (ry»36) ahoam

cu ©Tawing ll-C/2 - revlaed 6-13-<>9. See Note Y

above. Tfcla coar.octioD occura 12 tiara per typiceJ

floor.

7 . Corjectloria 13C thru 17C - Ho cnanae

8. Connection 19C - ruruUc, fabricate ead abip 3/4"

cblck plate* <Fy«30} moi abiis atock (PyTM36) ebown

03 Drawing 2-C/2 - revlaed 6-13-69. Sac Note I above. Tble ccnr.e-ccloc occur* 4 tiraea per typical

floor.

9. Tolerance* for quotations CI thru C6 and C8,c»ut to

out dlssoiioD over 3/4" butt platea { example:

19'-ll-3/4- for 20*-0" panel) la to be held to • tcl = rocci c£ I/O") or {- 1/4") lnclu«$i*so AST* A6

allowance for overrun on plate thlckne**. Vertically,

the tolerance on keep dtaeneloc oi i'-8-3/4" (connection

7C) cr l" fi-1/4" '(cooncc tlons 8C and 9C) la 1/16' .

10. All ehis atock to be *blpped In keg* by thickxe**,

Turulii. oi ill itu. s=t= c~ri:ttr- <?* ?-!/«" niar.ee. Fumiab regaining 1/3 of *blin *eta to con*l*C of ©dw-3/16"

plate.

NISTNCSTAR 1-1A, WTC Investigation 431
Appendix G

Laclede 8teel Zots$mny - * - j aDB \f>> 59^9

11, Bolt*, out* «nd <ra*bar» will be furul*hed by otbtf * , Laclede doc* not furol*). bolt lists.

12. ruml»b alternate qoote for 3/4" thick plata* In Py-36 In lieu of Fy-50 io Item* CI thru C6 aud C8. Tour cocneott 00 availability snd s f

f *e- 1 on delivery

date* for Fy-36 v*. Fy»5Q suterial are aoliclted,

13, In vlr» of the fabrication greater effort required

for thaao alnlntl velght butt plate* we fael tbe

fomui** In tbe Contract Booklet cn "Cxtra Hateriala'

are not equitable Tor thee* itee*. W* have therefore

requtested your asperate quotation* for tho*c ltaaa,

14. Should tbe Authority accept yo-jr quotation on itrai CI *nd C8 and^or Item* C2 thru C7 pl**»e advise ua

the lead tlae required free notification to convert

fabrication iiue £« these bolted alternate detail*.

5, With re*p<rct to deleted material ic Urn B, pl«a»e

advise o* a* to effective floor ouaber tor e*X*Siea» tonnage delated

end credit due to tbe Authority *» per Contract formula.

S- Ti**e 1* of the etieact and your prcopt reply 1* aoliclted

to stable u* to balance e*tr* reinforcing b»r co»t* eg»ic»t bolted *nd

usldtd cptloa*.

Sincerely

,

Malcolm P. Levy

Att»chiaer>ti A* per 7rsn*oltta> Ll»t

cci Me»*x*. S . Abrebaac* , IT. Brewer (8UC*). H. Ger*t»*n <T8£C), w/»tt

432 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Thm Vcrili Tt*dm C«ot«r

It rue tur«l Drrwicgt

Tr>c«»ltt*l U»t 335X Joot 16, 1969

Field Vtlda-d Optlorj »t f»oel JotT>t» >«». C»f

- floor* 10 - 20 + 6-?-£«?

• 2-C/l Connection 2C * 5-29-69

7-C/J Conn»cUon ?C 5-13-69

8-C/l Coan«ctlca 8C 5-U-69

9-C/l Cooatctlcn 9C 5-20-69

" 10-C/l Connection 10C 5-l*t9

U-C/i Coius«ction 11C 5-14-69

Fl«ld holler AlfnuO at fanal Jolotl

* 2-C/2 Ccanectlon 2C 6-13-69

7-C/2 Connect loo 7C 6-13-6*

8-C/2 Cocuwctioc « 6-13-69

9-C/2 CoM«ctl»o 9C 6-13-69

10-C/2 Connection IOC &-12-69

ll-C/2 Cooa-tctloo 11C 6-13-69

Hot* : * Ccoae-ction 19C «t»il«r Co Connection 2C

* At top chord only - bottoa chord ann" wth plate r«cuin

iwate aa haelc detail

NISTNCSTAR 1-1 A, WTC Investigation 433
Appendix G

Pert of 3ev Tork Authority

Offlco of tJis Construction ;una»er

20 Chturcti Scrowc

l!«w YoTt, ilav TCork 1000?

Attentiroi Hr. R. M. >tontl

f 9Tex.cc ; Th« World Trade Center

CootT.-ict WTC-221.00, LaeWio

riatc Trues Conaettor 13-C. i»el«de braulng

C«ntlc=^r\ >

Wc «ppT(Jvo the uso of J2 olitos PV1 a* fabricated J. S. AlbcrtCl Mid

describod In th« Ucl«d« lott&r d»ttd Jorv« 3, 1969 and »Wwn la tbe attached

Laded* sketch J3-13-91.

Viry tnalj youro,

STOLIKS, EIIL2, CEE1STIARSEU, ROiSlTSOS

JaDei Chlte

c-c uotora. L. S. Feld. PETA

3. Day, Lacbufo

A. Guttttatag, YP.CC B. D. JackBOQ, ?TX, St. Lot: 1b

434 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

de Steel Company Vne. No. zrs-/3-9t

Actual Lfhgtu vs. Speaneo Lf/igth of "Top

D/MEKSio/JS of Plate P9J of Co/m-zctor. /3- C

f e re-in- D

Plate P9i

SKUUNG - NEUE

OUUSTIANSEX - ROBEBTSON

Slru<lu/») & G»i! Enquirers

Amovu> *i notu)

A

* AcCoZ£ji,\'G TO LaCL££>*

£>W&. STJV.* PAT-SD

6-S3-68.

4 Acco!?£?/f/C. TO ACTU/.1

tf£AS'JZZ ?4E.\rr OF PCS

/// T.S. Albzs/ci's

f~/)BfZtCA-/,V& 5/-/CF

Dif'FflSlO/J

S PZClFlZD

A

8

r

0

E

F

13

'

c

"

i-r I/. " 2"

L ENG Tht +

12 W

2"

I "4

DeviAm on

0

0

NIST NCSTAR 1-1A, WTC Investigation 435
Appendix G

./t*/ti. fj.y/f/ June h , 196>-)

Hi . VJa.>iic Brewer

Skilling- He He -Christiansen -Robertson

230 Park Avenue

New York, New York 10017

Pear Mr. Brewer:

Re: World Trade Center

Contract WTC 221.00

Material Supplied J. S. Alberlcl Co.

Presently the J. S. Alberlcl Construction Company which fabricates

the truss connectors we supply for the World Trade Center has 22

oieces of our material wnich is 1/4" under the required width.

These pieces are 12-3/4" x .500" x 2'1-3A"; they should be 13

,! x .500" x 2'1-3/U". Alberlcl has already cut this material and

notched It as shown in the accompanying drawing { JS-13-91) . These

pieces which are to be used for truss connector mark 13-C have

dimensions which correspond to those shown on Laclede Drawing

ST-2"4 dated 6-13-68 with the exception of dimensions "a" and "F"

which are 1/4" shorter than the corresponding dimensions shc\m in

ST-274.

The only problem involved with using this short material would be

that the length of weld between truss connector 13-C and the horizontal bridging angle at their connection point (see attached SCHB

drawing 7-AB4-13) would be reduced by 1/4" top and bottom. As far

as fitting the truss connector there will oe no oroblem since all

critical dimensions have been held.

The writer requests your approval of Alberici using the above mentioned 22 pieces in trass connector 13-C. If you do not approve

of using these pieces we will have to supply new material to Alberici

which they will have to cut and notch. This will require a considerable amount of extra work on their part. \

CC: Mr. Lester Feld, Planning Engineer

The Port of New York Authority

111 Eighth Avenue

Hew York, New York 10011

Mir ti l (Int + onto (7 t>Ti> lert ET!*T i

r*?"?r Tishman Realty & Construction Co.,

Inc

.

30 Church Street - 11th Floor

New York, New York 10007

Yours very truly,

LACLEDE STEEL CO

David B. Neptun^

Product Development Engineer

Construction Products

436 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SHILLING, H ELL E, CHRISTIANSEN. ROBERTSON

CV«n»uft»iig Structural and 0»*/ S «jj»m'i-»« .'>" f*n»4 \vv>rur Vru Y«.»fc. V V W>i~ Mu

john 8 ^killing flrfijr J

I !<«fft |«f»«l \ VIwHwumU f r n'u- J !<••/«•<( s...i

Mu n..»-t

.

!-..,£•>> 1- I...*—,

Port of Sew York. Authority

Office of tie Construction K&nsgcx

30 Oaurch Street

Hew York, Kev York 1CO0?

Attention: Hr. K. a. Hontl

Reference: The Wovld Troxic Ceotox Contract KTC-221.00, Laclede. Out—of -Toleracco Fillers

Ceatleaan:

Attac^sd Co this letter please find s xerox copy of the Laclede letter to SI'.CR dated Decesber 8, 1969. We epprove cu a one time basis only the deviation*

in filler poaltloos deacribad b7 Leclede for 160-C32T11 crusacs. Hr. Bay

vaa tiviaed by i-be writer by telephone on Thursday afternoon, Dccaaber 11, 1969

of tbe above apprc-ral.

Very truly youra, sniiiKc, ariLs, Christiansen, robektsoh

Jcnea White

CC •' Kmbtb I Fold; PNTA

V. Borland, PNYA

E. Bay, Laclede

3. Jackaoo, PTL

LEB..UAB.

C ft 4 • • \ . « -

. O - * - » *

. O * * * ' - ••«

NISTNCSTAR 1-1A, WTC Investigation 437
Appendix G

December 3, 1969

Wayne Brever

Shilling- He lie -Christiansen-Robertson

230 Park Avenue

New York, New York 10017

Dear Wayne

,

l60-C3f?TI treses were fabricated this week as shown on the

attached print. Note that the three fillers on the core end were located approximately l" more to the center of the truss

than Is shown on cur drawings. Three trusses have the third

filler 2 more than shown on the drawing. All these trusses »ere inspected and accepted by PTL with the provision that we obtain approval from you for the location of the fillers.

We therefore, request that these trusses be accepted as fabricated. Please answer by letter or telephone by Tuesday,

December 9, - 9b~ 9 > so that we may continue with our present

production schedule.

Yours very truly,

LACLEDE GTEEL COMPANY

R<tt>£rt D. Bay f\

Director Technlcal^Services

Project Coordinator

kjj

438 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Es END (COLUMN)

El END icore)

60 T T C*«l CHORD 'MAIN WEB

TWO ANGLES • W- FiLLCR r_

. i iccl 1 sue j

1

. ;. TXPCSTCEt —-—

i

' NO; Of f. 3CC KOTC«» NO '

j pVA

:

;-7 1 A2 42 | 2 1 !^"x J2 5'lS3 | 3' A242 92 .1.2. L92 •

NISTNCSTAR 1-1A, WTC Investigation 439
Appendix G

SHILLING, HgLLE CHRISTIANSEN ROBERTSON

( r,.:., r; , t _ Sr,„ H.J, ..,./( ; J',,i \ .. v. \ i r ...;- \|,.

* i

ti ,. > f M

Port of Scv York Authority

30 Thurc*' Stre^i Sev Tori, "ov TorV 100O7

Atteatleo- ;ir. it. w-o»ci

Scf ercocc : TS« VorlxS Trade Center

Contract VTC*221 .00 , Laclcdo

Scpalr rrt>ce<I^T3 for Vertical Struts

Genr ] cbOc

Plf-ase refd to the Uicledc Utter to fKCT. dated .'on* ?, '."Jfel tr&nxni t r lev

tr"* L-»c mof oocw>»?t titica urpclr rrecesitire Jcr vertical Struts cs Z2~ TVuos^a" <5»t»d Jur.o 5, 1969. U* approve tho &bcr»-e repair procedure «nd

t*>o attached Iwoclcd* drawing V-7S-1 dated Jusc 2, 106?. We attach koreto mt *oroz c^tt cjtc 1

" of the Laclede procedure and 4ra«lci ot«=r«d * epprsyved

07 SHC* and Initialed by the writer.

/or- truly youra

,

SUI1.LXT*;. 'TTLU:, ntHlffTlATlRES , H03ETTS0K

J one* CMts

« cay , i-acled^

J«7t!

440 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Mr. James "..hi to SKiiIil:{J ""ncIxc,-

vJ jji.jLili«it'i5Ci. Hob CT t C< O V. 230 Park rtvenue New York, Nov: York 10017

Dear Mr. White:

Please find attached "Repair Procedure for Vertical Struts on 32" Trusses" and drawing W-VS-1 dated 3 June 1969. Uith the

subxissicn of this procedure, formal request is made for approval to repair as necessary the vertical struts on trusses

furnished under WTC-221.00.

If there are any questions, please contact me at once as we are anxious to obtain fortnal approval for this work.

Yours very truly,

LACLEDE STEEL COMPANYDirector of

Technical Services

CC: Mr. Lester Fold, POKY

A

Mr. R. M . Monti, PONYA

Hr . Al Guttcntag

NISTNCSTAR 1-1A, WTC Investigation 441
Appendix G

SHILLING. HELLE. C

( lilJ.I.' \fru. fJi',7 .fit./ ( J il.'" 1 -

July 3, J r»'•', rile : utc z::c

MRIRTIAN SfcN, ROOtRTSOM

/t>3f p't t J-'. 1m»|

Port of New York Aulhori.y

Office of th:> Construction tlanager

30 Church Street

New York, New York 1QO07

Attention: Mr. R. M. Monti

Reference: The World Trade Center

Contract 221.00, Laclede

Repair Procedure, Trvsa Bearing Ends

Ccntl cr.an

:

Please refer to the Laclede letter to SHCR doted June 3, 1969, transmit t inc. the L-aclede document titled "Repair Procedure, Tr-uss Bearing Ends" d.ited June 3, 1969. V.'e approve the above repair procedure and th*> srrsi-WJ Laclede dra-I'tt, w-Bt-1 dated Juic 2, 1969. We attach hereto one xerox copy each of the above

procedure aid drawing staoped "approved" by SHCR and Initialed by the writer.

This approval does not apply to double diagonals, which must be welded all

around as shown in the attached SHCR sketch dated July 2, 1969.

Very truly yours,

SKILL1NC, BELLE , CHRISTIANSEN, ROBERTSON

^James White

cc: Messrs. L. S. Fold, PNYA

R. Bay, Laclede

B. B. Jackson, PTL

JW/sl

442 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

June 3,

RD'AIR ) R,'CK!>URi:

tkuss j) i : i; 1

1

;<t km.-s

The fullowin"; pj-f'-edtirr is written ti» cover the repair of bp.it'ing

eno's on trustcs providfd for Lite World Trarfc Center Project under

Contract UTC-221 ,00, Such repairs tli.it r-my be necessary from time

t«> time will nc-jrually 1>l iiade ci the Madison Plant nf T.aelcde

Steel Ctu:t,>nny and > ny iuvoJve one- or oiirt nf the lettered veld? on drawing W-BK-1 dncd June 7, 1069 which is attached and o part of

this procedure. ;'rir.*arily the repair we 1 el's will be wade to .ndjiist

the bearing depth of the seats \*hich have a tolerance oF + l/S".

Under the supervision of the Certified Arc Welder Foreman, a (>rtif'cd Arc V;c5d r i:i ] ] perfon- the ncces5.",.»y repairs. The lettered

joint to be repaired will he burned snort with a torch. All i-.vld splatter ire . the previous rcc I f. r.nice veld v;i 1 1 be rci*K»v»rJ fnn the

serffceo to !«<- rr-.-.O «>od so ih.-it there is a elenn surface of h-t'.s

rrct"! 1

. (If lb'* 1 (• ir. already separated, burni-V. uuuli -. be

required but rei.^v.1 of the wcltl rplatccr i.oteiiol o-ust be n nO."ipl i r bed . ) With reference to the dr-.wing, W-DE-1 of the particular lettered

joint to be weldet!, the mr.v*>crs will be- accurately posi t ion^d end

the >••!•!<.': «^ "I lis:" jviii ..'1) \.c. ?** /•//*<vrd"in-- , e with the

existing pr»»« eOuf. s for a;\ uvlJIri" .."liich Jir.ve bce.i p

,- cv jov^cl y approved. The di: .tnf ious of the welds which arc full -length shall

be in Pccor«ln^cr i.'Ith the tobje on dravin ST290 Osicd Ft-brtMiy 2A,

12:1.

Toe repaired trjr r. r ciud v. 1 ]i' r, ] 3 be inspeftod .-u' tested folio.

the rr.sl iiy t. '- • i p. oc edn'-c: which arc Malcd in Section 1 O'j Quality Control r,:-C liv,c~t )> n, V'oi Ul Trade C<m<-r 72i.^';.

NISTNCSTAR 1-1A, WTC Investigation 443
Appendix G

a

sakyisiiuajfi

SECTION X-X

IERIAI "CO)

MOLE CCKTCR OIST. fH C.U)

TO BE NAiRTAlNEO AMD

MftO IN ACCORDANCE

WITM THE OR AWIRO .THAT ORLtES TO THE PARTICULAR

TRUSS RCPAialO.

H.C.D.

COSE END

NOTES:

1. ALL ARC WELDS TO •£ MADE WITH LOW HVOROOtN

- ROD *M THE I-?D SERIES OR EQUAL

.

2. ALL. ARC WELDS fULL LCWOTM EACH ilOC AS IHOWN.

S.ALL ARC WELD S'ZES TO 8C It* ACCORDANCE WITH NOTE I Or LACtCOt DRAWING ST 290, DATED rE» 2*.

SXUUKG-Haif

CM^rsTu^syi-^OBOiua^

SbtKiUrtl o <t*ji

Zi tfSUBMI! '

LACLEDE STEEL COMPANY CLASS; WOfi.0 TRADE CENTER

w£LO<NG PRorPQURF f OR RfPAlfl Or aCAWPSKS

»*».„

>>L».

444 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKiLLING, HELLE. CHRISTIANSEN. ROBERTSON

f.'nn.\(i/rui«; Strut twat iiml Cm/ Fn^jmvr* • !>•> J'j't Inimr. No. > . .it \ } )'»')" \/t. '* I

l'n/i(i H S'fcWifti! • IM^r f /!«•'/« /< ijn X ? >j/i«f«.ii««»i f I- »v»lx-fl»i«i

\< \ («•««»

i Kvnri March 31, 1969 J — />'•

'

?ort. o? Tor* AutLorlCy

Office of the Construction Hieeger

30 Cburch Street. Roor* 1030

Ncv YorV, Hev ^ork 1C007

Attention: iix. B.. M. Kootl

Refirence: The Vcrld Trade Center

Contract VTC-221.C0, Laclede

Rework of C32T1A Trusses

Gentlemen

«

Please refer to the Lcclede letter doted March 18, 1969, requesting

•pprovel for the repair of tve-jty-four C32T1A trustee. We approvo repair

of the subject trustee by dcufclt— strutting with or. additional 0,75" bar

aa 5ho>o In the Laclede repair dro^lnrj dated March 27, 1S69, a copy of

which woe attached to che Laclede letter. Otu> copy each of the Lcclede

letter ccd the attached oLetch are included vith thio letter for yocr

reedy reference.

Very truly your*,

SX7U.IKG, HELLS, CSKISTTASSIS, RCSSUSOS

Jane 8 V>"hite

JWrs Enclosure

cc: Mcosre- E- Bay, Lxciedo

L. Feld, TrTYA

L. Telcliaeter , ?TL

K tot*

NISTNCSTAR 1-1 A, WTC Investigation 445
Appendix G

THE PORT OF NEW YORK AUTHORITY

u.-' i iLaclede Steel Ci*:iiiaoy Arcade Butldinc

St. Louis, Kisoourl tojIOi

Attention: Mr. Robort D. Buy

KB: The world Trtfde Center

Loniruct HTC-221.:).' t-dtl-^c- Rework of C32TIA Trusce*

Cattlemen:

He approve the repair of tventy tour (2<») C 32 TIa Truo.ico by Ooubicscrutcins with on &jjcittoat>l C.75"C bar as fhov.i on youi- .-.ketch Ootod

M^rch 1?, 19^9 occ<rzpar»7-lnp. your rctjuent letter dettd M*rci. 1

"> , lQbO.

Very truly yoor9,

u , C. tor 1 oi.o tn- inccr of r^terlftlo The Wori<3 ?roic Crnt cf

DC: >le*sr»: ft„H„ Kontl

J. v ft- <s Ci)

446 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

r/

# S/c't'O. //<±}cr,u <>3tP/ March 18, 1969

Mr . Wayne Brewer

Skill ing-Helle-Chris tiansen-Robertson

230 Park Avenue

New York, New York 10011

Dear Wayne:

The 24 C32T1A Trusses have been fabricated at our Madison

Plant with rhe V3 and diagonal strut on the column end with

1.09" web stock instead of 1.14" as shown on the approved

drawing

.

We request that the trusses be approved after repairing them by

double strutting the diagonal strut with a .75 bar as shown on

the attached drawing.

Request for Approval of

Reworked C32T1A Trusses

Yours very truly,

Kabert D. Bay

Director of

Technical Service

NISTNCSTAR 1-1A, WTC Investigation 447
Appendix G

si

N

ft

SiH

"1 1

(fx

MAR 21 1939

SKIU-ING-HEL1.E CHRISTIANSEN - RCBER1 ^ON

LACLEDE STEEL COMPANY Cl-ASS:

W«ld Exf 11 for Repair of C32TLA , w with 1.Q9'

Dlagoml Strut.

Data March 17, 1969

448 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Juao 6, 19 6^

Tore of S*v 7orV Authority

Cffic* of tbo Construction Hanocar

30 Church Street

tfev York, liev York 1000 7

Attention: J!r. R. IS. Kratt

!ieforr.oco: The '«'orld Tradi> Center Contract UTC-213. 1 ''), I'D!! Po^ilr of v lr«to "d". "accl J JO 'J

Cc-atle=uin •

Plcoao refer tn cIk: \'V:'. letter to PW.\ darnd ::ay 23. 19ft!J. .'«'DT report -iKonte

3 cod 4 cotrplote our T'.-cordr, od tVic referenced ropnlr. '-'e, toernfore, approve.

I'odcI 23C'3 ac rcpnirad.

Vory truly yours.

SJ-.ILLItiC, liJ'JLLf . CTja:iTlA^3?j;, P.OBCKTSO.:

Jsaes vtiice

cc: Hcien. L. Teld. PKXA

>;. y id»i, run

Cnff^ry, .SIB-douoton

JW/lo

NIST NCSTAR 1-1A, WTC Investigation 449
Appendix G

SHILLING. MELLE. CHRISTIANSEN. ROBERTSON

Cw.AUnizSUxHlv'ei -JUi/ fcW i'<>£f ."•"fVt liiW, \Y>. Y-'l \ \ )<<•'!' Vtt •> SA~^

?«{,,, f? \kt(h»£ fM» I »«•"« M"» V ( fc" hl«u ( f K«.f..-»JM.„

u \ );,,•,..-<

-L.'!.<'!(.

Voy 196*

Por 1

: o/ l?ev Yoi-f Aur.'icrtty

Off Jcc of cf>p Con-inrucc ton Kiuvacnr 30 rhurcii Str^ot

N'cv York, fork

Artontton: Hr. a, si. ttontl

Scf**rcneei Tfcw Werl<l Cfint-sr Contract k,7C- 713.00, PlU; Scpnlr ot ?t/»tv"c ', P.-incl 220B

CVsTi f 1 rem

:

Pl*nf» rofirr to die PP" letter to r.W/» datecJ .*'ny I. 1969. «e approve the repitlra

<lt>scr i )i«ecl cootirirujjc upon rvcui^t fron vii'i of eorifimlni: 1 reports.

Vwt-» truly ymira

,

cc- »?r. L. ?elH, HIT*

Hr. «. Vtsh. KnH

"r. -. CcJzur-/, Sib (Hcn-iton)

450 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

iPDM

PITTSBURGH-DES MOINES STEEU COMPANY

I!ny 1 , I960

Tlio Port of New York nutnority

30 Church Street

Now York New York 1 0007

Attention: V.r . R K. ilonti

Tin-Tor ar^r* • r|i« 7cT ? d Tri^S Cc

Contract lfTC-213.0

PD:i Contract 1 707B

Gen 1 1 omon :

f.'c aifo Beiiolnj you for your rocord and approval one (1)

copy of our repair procedure ahoeto No 1 and 2 Dhowinn th© rc- patro of larainationa co found in Plate "d" Ponal 2303.

Thoe« repairs wero via do In accordance with the "Investigation

and RepaJ.i- of Lamination and Other Discontinuities'* dated liarch

19 iOPt*. They wore witnessed by your inspector Mr Dave Caffory

of Cwuthorn Inspection

Picose sond os a 'otter of approval for our rocord

Vflry truly youra

PITTSBURGH D2G L'OIIJSS STEED COSTPMJY

U. M Fioh

Project elona^or

ITdP:fcsh Eqc cc : Skll 1 lng-Hel le-Chr istianoon-no^ertaon Tlshean Realty and Conetr Co

230 Park Avonuo nth Floor 30 Church St.

Kov York. Sow York 10007 Hew York JJcw York 10007

~^„Attontion: [Jr. Jcs;e3 STiito Attention: Ur . W Guns tan

n

,—j P1 uc one copy

ANMIVE RSAKY

7

NISTNCSTAR 1-1 A, WTC Investigation 451
Appendix G

:PDM

ami in.. toot; con r, luuc' O"*, PITT5BURDH-DES CVJOIMES STEEL COMPANY

llay 33, 1069

The Port of Hou Xork Authority

30 Church Strcot

Ho-* York, Wow Yoiv 10007

At tout ion: Hr. M. ttontl

fteforonce : Tho World Trade Contor

PDH Contract 17078 & 1713B

Repair of Plato "d", Pauol-230B.

GfDtlor.en : Reference to 61ICS lcttor of itiy 16, 1969, to Hi". H.

M. Monti approving our repair procodure to plate "tf" Panel

2303 coatincent upon receipt of our NET reports.

?o arc enclosing for your records one (1) copy of ouv

i*ZD? reports Shoots No. 3 and tio . 4.

Unleso to henr froa you ue -will hsbueo that this subject

mat tor Is finalized.

Very truly yours,

PITTS2UEGH DEB KOIKES CVCIX COHPA37

U. H. Fist'. Project uan^-cer

Ekc . CC: Cltiilln—llclle-Cur 1st iancen-Bobertson Tishnan neolty Ih. Coustr.

230 Pork Avenue U*b Floor, 30 Chureh St.

Kep Ycr!;, lis o Yorlt 10007 KewYorii, t'oo Tork 1000

5>>Attcutiou : ar. Jarace '.Thlto Attn: !£r . [i. Oorfitcan

PIub one copy /ZJth

ANNIVERSARY

452 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

JXL3B_

Co/,. 2 30.Q

l/c/tc/ (uc/</ tv/Yf/

Ut fo Ojck OP 6<J/-. /vSS "' So Ct/yc */ /Gs./f. Co /'/-//*. to C /</ OStrrq -^O/t l/C^ • ? '/SO //a/ G6h

f ~— —

s~K—

8 Itkz.

]

1 VCf- in b //-a/ O to |j- *

/// G-'J" /e/*?//f ^4

//

1/' / c-f ) s&mt

p

3. /I

TTr a.

I

4"

\

'\ T.

leavvtio \f bo/i-JfiCif «^ <2^<a Crete Ct/ta'f'o/? o-< f£r. f

fPanuoj-! fO a /-/:? /S J /oj< J'o (JSC back On hat- . 'ro //// U o/'d. (^JS?

bclt-JCO.'-i 'f- B./:d couoi- bfafo c/

NISTNCSTAR 1-1A, WTC Investigation 453
Appendix G

/aw <„ e (d torn m fx°j* "<'j*->?z

L6o f 7SO f/vt <

. J7/38.

Co/, 227

B

serf* ^->Af

( a.)

> f x

, w-^ljW.llJI.

, =- >4 •

5 .>>

a * no

M£J.umJk s

hank up boi-s l y'3cfSQ</ f ' p/<r/$, }//>/'//C/r tttyfotfa/'io-Mfak

454 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

PDWl

PITTS3URC5H-DES MOINES STEEL COMPANY

l!ny 1, 196<>

.no Port if Now York Authority

* n n' ect

rork New York 10007

Attention: lir . R M . Idontl

Rofei oncer Tho florid Trad© Contor

Contract WTC-213.00

PDi! Conn-act 17078 £c 171 33

Gen tl orcen

:

V!o are sending you for your record end approval ono (1)

copy of our repair proccduro ahoote ?.'o . 1 and 2 Dhowin^ tho repairs of laTelnatlono os found in Plato "d" Pan^l 230D.

7hcB& repairs wero wide in accordance with tho "Invest tea t ion

and Repair of Tsarina t ion and Other Diacontinult lac" dr. ted liarch

10 1068. They were wituossod by your tnopoctor Mr. Dave Caffory

of Southern Inspection

piocso send us a lottor of approval for our record

Vory truly yours. , .. PITTSBURGH DUG tiOIHZS STEEL COEEPAMY

« u rush

cc : Skll i inp-Hol lo-Christ lcnoon-RobertGon Ttebman Roolty and CosDtrCo.

230 Pork Avomio M th Floor 30 Church St. How 7ork. Now YorS; 1 000 ' New York Row York i GCG7

">Attontton: Ur . Jcmec Vhite Attention: Mr. 11. C-ersrann

i p' ua one copy

A f\J N I V E RSAPY

7

NISTNCSTAR 1-1A, WTC Investigation 455
Piltisbui-tfii-Des Moines Steel Company

ULTiiASOHic kepout fohm

ULll CONTRACT 11 ) 3 ff NATEKJ AH _f y 5 [.it /)"UV.'..P.

THICKNESS ( -^/^

'

' 21

DRAV.'ING , V />

r?OQ !? EQUIPMENT U S K 5.K

SEARCH UNIT , SrRAlj^HT, V. /M»"t FREQUENCY - SUE P. g <m l it - tSE

SUR FACE FINISH 5mp XJl P1KCE llAHK "D ~

'

CAL1DKATION CLOCK c; piltoP /:) r :,: nZ

coupla;;t CJLhJi \ih ov:

BASIC SEiiSlTlYITY a, [?, ULTRASONIC PROCEDUR K USED fiM'M

IIETUOD USED "/f'f. T TECinilQUE USED \>^--'..Z i-r>. PERSONNEL QUALlT'I CATI OiYS

' WITNESSED DY ^ -(^ C^z^A^t-yf

OPERATOR C . \/ t

SKETCH

DATE

^- - C 9

T i OH

$2" -r- *- • — r " ; *

• -5

.

Visual IndiOITIoK s 3 >

..-1

f\ K t r\ Go^\ c t \) \L>\ c r. F. ]:> u )?

Couc-r-o To /

*'; /'r" i'VH

456

NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Acrn ~~c err Herr.t.? err.- /;P"rr//7 $ai>$//f$ A.'/D hizof,-/.-} -

/{•? V„,v y /%'}/,'</<? .r ;&"<=>'/>. (vtr/bs }

Ry.l/Ur/i T £.?/7 r'-- />/:•;: /)/.? our *>C*FG*IT'&? /}/rC/).

r , 3 '' \

22-5''-; i-.'rsch o,vC7 Pass opt'/ssSO, o:i/t>J>; £/-0c.r/ja;}^ vrz-^c

i'rTt >':> ; tJ<///'7 {TyyojS — ///. Cj ,'JACt'i V'j a/- i/S.X&tJ

S.'.C'.S ~° <ff2/.'/3 /}/JJ> /.<.'/'£//£"?.':'— C.n U. T. C t tfipi; 5'P'

NISTNCSTAR 1-1A, WTC Investigation 457
Appendix G

SKILLING. HELLE, CHRISTIANSEN, ROBERTSON

Consulting Sl'tn1ur>il ami Ciwl i-MsiifuV" - -

;,! (**'* \irm... N.'u- Vi-i.'. \ 'i (*W}~ • \J» 'iSS"4

/»/»» H Vtrf/inw • Ni'fs* / Mi'Mv /../itr \ ( /(H.Iwwm » I < vl«- I K-.K^.m

m „.„. » ni^i.,-1

(cMp^i ! fetkfttn Hay 19, 1969

Port of Nev York Authority

Office of Construction Manager

30 Church Street

New Tor'*, Ueu York.

At*.t>.tjci<m : Ur. U. ii. Monti

Heforrjucii : The World Trade Center

Contact UTC-213.00, PDH Repair of FJoce ' V* , Panel 30QB

Cent leaen '.

Plcoflc refer to the PDM letter dated tiny 8, 1969 troaeoitcin^ 3S * 11 sbeeto

1 through 8 inclusive describing repair procedures end including reports of noc-deot ructlve t«ot r<i«uits for repair uorlt Oo plntn "b" , Yanul 300?..

Tbe repair of pinto '*b" ts. approved &s tus the final repaired veld, pluf?

"au" to "h", tLfl documented fcf IJT test on Hoy b, I960.

Very truly yours.

SKILUIKC, liEULK , CHPJ STUHS2N , nf>B£RTS0U

'J. Cnffcry, SIS (iicunton)

458 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

PITTSBURGH-DES MOINES STEEL COMPANY

H»y 0, 1569

The Port of New York Authority

30 Oiurch Strcot

New York, New Yor't 10007

Attention: Mr. U. . M. .Monti

Reference: The World Trr^c*e Center

Contract WTC-213.O0

PDH Contract 17076 5 17130

Go nt lemen :

We arc sending you for your record and approval one (1)

copy of uhcet6 1 to 8 inclusive covering the repair procedure

for repairing a crack that developed in Plate "b" Par.el-3008.

This repair v/39 oadc in accordance with the Investigation

and Repair of Laainations <-\nd other Discontinuitieo datod on March 10, 1909. The rop-^ira vexg »*it no6Sod by your inspector

Kr . Dave Caffery,

Please eond us c letter of approval for our records.

Very truly yours,

PITTSCflVGH DES KOIKTES STEEL COMPANY

H- M. rish

Project Manager

HMT:koh

Enclosure

/ -^killing- He 1 le- Christianscn.floosrtson Tiahman Realty ond Constr. Co. J-^-fiAx^Mion: Mr. ^ncs White Attention: Mr. M. Gcrstoin

ANNIVERSARY Plus one (1) Copy

NISTNCSTAR 1-1A, WTC Investigation 459
Appendix G

I

^3) Mt To tf/*c Sur.< 2>€frrtr ;;S EW-ev/ED.

(0 Cweck'. Cor^ETirs I^slu UJjtw [j.T T»Jt/5 r<7/o*J (-Oftoewc-arTo 115/=

(<*) Fit^joVJeuS R M

Aijd To 3e7;i:-cv/»Cf/ri~»,

3

5ecT i ow A A

460 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

PITTSBURCH-DBS MOINHS STBCL COMPANY

ULTRASONIC' HE PORT PORM U-9

WORLD TRADE CENTER

Contract No. - C^rS- 17 1 30 Material f V '/ t - J" } Thicktiass i >j? Joint Design

c

-)

. So /^ Drawing

hp Si?

Equipment - USKSJ'

Trnnsducai: Arrgle CCP" - 70°

Praquoncy 2.25 HH2

Calibration Block Btioic + IIW Couplnnt: Ctfllulooc - ,er^£uSsv?>-

Da to

Pc. Mk

Tr onsducor

Anglo

Inspector - C.V.

WELD SKETCH

Wltnooocd By

Ah 4

CB Rating Length

7-t>

Angular

Die tonco

2.z

q'opth Remarks

<^/?/9<r/<r

TotAl Lek>gjy

Of. N EU-P

5 m* f c

NISTNCSTAR 1-1 A, WTC Investigation 461
Appendix G

-v f| THF PORT Of NtVVYORK AUTHORITY

V\«Hl|| I i.i.l. ! .I.lh 'HI

May 5, 1965

Pictsburgfi-Dcs Haines ^tccl Coopony

Kev i x 1 v i ? i «vJ Pittsburgh, Penn-.ylvoaio 1 5225

Attention: Nr. II. M. fish

Rot The Wo;'.<l Ti.-.'i'j f.f.-.ter - '.ottiact V^.X' - fii:

Cent i cacn

:

T"urthcr to your letter dated February ^, !>{/), the -ub-.-K. -csibiy tor Colurm i, Pcncl f; ccn.-p tnt; »: ci :abricnted r.a<j nay b«. incorporated iQto Pane! 200B.

Please note thol rtpprovnl I <» jlv«?n only (or this particu.nr

sub-uJ5C=bly. !u the event of <iny : id Icr tnitancc, approval vi 1 ! t>f gives, if vcrrifilco", on a unit by unit ba^ia, i! tci r,<!trzi 5 -loo o! ri-sr.pt etc

<5cto for nuc!i 1 1 v i<ju.-jl cos:;,.

Very truty youts,

Construr'. Iqtj Mauas<sr The Vorlil Tlnle Center

JS.t ( jjw

cc: W, BorJnnU. J. White (SliCM

462 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKILLIN6. HELLE, CHRISTIANS EN. ROBERTSON

OicMi/ii/ii- Si»i«i)(fi« iiut! tr/vil K»ijj«»«vr» f\i»t \>» iifn- NV« V>ul*. S V Mn)i~ • Stu.

/«/») H SbNiife: • IM&'f Ilrffr M'" x t •»«»«•» Irvfiif* Hofvrfiori

^ Jirn.ji,"^' W ...... \ MiriMi

March 20, 1909 ,. . . ,

.

fort of Kev York Autiicrlty

Office of the Construe tion Harvapcr 30 ci-.urch Strep;, r...oc 103r<

l«ev VorV. . Pew Yorli

Aticntior. < ?ir. B. M. >!onti

Hcforrncc: Tt-.o World Trorln Cvntvr

Gcntli-aoo:

Fl^o«<c refer to tiic TD" Loti:«r ictcil l!arch J ; , 1-J6S rr^uoctln!: i^provM of places "b" for pens! 33Vti. Ecsi'.d irpcn our to luv-nont* rcvii'j of thin cotter

uir.ii t . L. Col/jroccl cf PCM, uc uprrovc ti-.e subject platct* nr. repaired

CB3t!nrc3t tl»<on PIT' f urc ] i:u- P:<*Y/i cum f.l'CK vil-t r«.v::vJ co-lcr. '>;" "L" tfcit report/), r^f c if ic.-'.ii •/ {.Cr-tln? tt-.r tiiac, loculTM :t:ui -urr>r:*in of

Vrr? truly yrurn,

suiLLEic, hill::, ciiristiat.so;, RonEnxscu

(J . D.

:. Fcia, e;-irA H. Fieh,

NISTNCSTAR 1-1A, WTC Investigation 463
Appendix G

SKILLING. HELLE. CHRISTIANSEN. ROBERTSON

Juno 6, 1969

M.,i>i.itj>-i \> ... i. 1 )<.,-,..,

Port of Ucu Tork Authority

Office of the Construction Manager

30 Church Stroot Kew TorU, Kaw Tork

Attention: Mr. £. H. Monti

Pjjfcreeca: Tlio World Trade Center

Contract V'C-213.00, PDM Kopair o'. Misfits. Fon«lc 227t rjsd 230n

Centl*r»*nt

Plftaeo rofer to the PDM letter to TXfth detiid li&y 23, lOG? and attaching rerviued repair Bkatchcm. Ue appro-va repairs to Paoela 227B end 230C at ahovn in the

tVH sketches dated 4-11-69 and revised 4-16-69 to ohov complete repair <let«ile.

Very truly yours,

sr.iLLiHC. mxix, cimstiAJJsar, Robertson

James VThite

cc: «r. L. Tcld, ?trt\ Mr. II. J'Lcti, rc;i

tlr. n. Caffery, SIS HOUSTTHJ

JWjl

0 » » » P

464 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKILLING. HELL E . CHRISTIANSEN ROBERTSON

C!<>M«ta fJii:s StitH'tuul 'ttJ fiv« I IfiUhVj* - J»l> f'./'i \>nir«. \,l> Lit. \ ) J'kH" Mil 'I f

/o/)» J) StifiiUi: • I IM/« M^i V <<,,,.,..<«.., I oh.;.'}' K..K -f...»r

V(,( n..v.< « \ By..,;'

i ^ . •r'.f.t'v-i.

Hay 16, 1969

?ort cf Totk Authority

Office of the Cor?>truccioD Stanajt-r

' - "or., .:• . f^re

<«tt«:ntfor.: . y. ?. V.. Nor.tl

?i f orcr.co : The World Traiio Ont«tr

Contract v,TC-2l3.:'0. !*HM V.iyil- of •-•lsf/f*. Tm»:jo13 227» and 230B

C?Dtltr-cn

:

I'lcoce refer r_o t!xc rDti lt»tt«r to HITA dated April 15, J969, While w« are confident that tb>? repairs described }u th*1 tv> (?) .Tttneuerl IT)"" re:**Jr procedure

ar-.actu (out iiuJii^*) jf>"{ cr.o -Ttic 4-ll-«»9) am ccuplclcly ^at t Jf octory . -.v vU.1

ri-jciru «il&<tcu.. oi tr.t tctnil -»ald joints and all other port lacnt ^ita 'jrforf

>.-? too Lt«u< f o n. J- 1 approval of eta subject rcjmlrs.

• ury trviy /our*,

r. .'. Curtcrr. SlSOloaaton)

NISTNCSTAR 1-1A, WTC Investigation 465
Appendix G

' I > < * ."Vl O f > J

?, I Pittsburgh -Des Moines Steel Company

^ Mtvnii isuho <>'iiseu«c» h(kiisiiv.«ii <i;j! • a»c* codi *»*

April IS, 1DC9

ilr. ft. tt. Monti

Construction Manager

F.ooo - 1119

Too Port of New York Authority

20 Church Street

Hew York, Nov York 10007

Be: Toe World Trado Cortcr

Contract WTC-213.00

PDM Contract 17078 £t 17138

Gentleman:

to are sending you lor your rooord and approval one (1) copy

of our repair procoduro for wisfito on panols 2273 nnd 23053.

Cotli of those repairs roquirod fcbo addition of 2 r. l/'i bar

up bare and additional welding as explained in detail on the

attached sketches

.

Pleaeo favor us with your written approval of those repair

procedures

.

Very truly yours,

Prrrsiiuuu^i-Diis uqwls ssteix company

a. a. Fish

ProJ act Manager

Uijf':g.jh

j i ^ i~ ~— Pel 1 C—-Ci^T L- t r. - - -, r.O^*ss t.P-.:... Park AvCD'JO , iie-sr York, How YT?£fc 1C0C7

Attni ax. Jaasos Phi to

Ti&hnaa Boalty t* Coastr. Company

lltb Floor, 30 Church street

new font, uev iorfc i0oo7

Attn: Ur . U. Cei stioan

HAMMOND PRODUCTS

466 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

fx 5 *

Approval fc eie ved frotrt Tftr. M ft* h J/:'°.'< <t j. ,/<». irtakt

Up..xit ffe.tr *nee trt u>id+h of pi*t*s *Lr.f AnsS**.f

l>t*ek -Oft b*rXt itxtkeJ ~fb f- pl*t<* \jrlffaH Gppt-oVSf to -fo//ctO,

NISTNCSTAR 1-1A, WTC Investigation 467
Appendix G

I N

/

P.

L

in fs)r/jr<9 »V 1 7" zjf crsfigt ^

hvHc-^i 3 -• s/<s ft*/*/ j/ost**

/<fot>/*f ? hett-J***-' i

1*/* 6jf esq Chafe Qm</ fh>/? of /Zt f . fPe^utsi pahfHt j 3*om* /~o use hack op h«th~ , t> ft//Mot </, $£L*r

468 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

S KILLING. HELLE, CHRISTIANSEN. ROBERTSON

VI „>.,, \ M»nn

H-ay 16, 1969

Pore of New York Authority

Of F 1 co of the Ccnr.tTwzzieo ftannser W C!.urc)-. Sl.i-ti.2t

•.<.v Yore, Tor*

Atter-.tior.j l-:r. 5., t'ont;

"ifcrcacc: The VoiH 7i-«i2c C.*nE«r Coacract W7C-2.13.CW, P7W

?jep/ilr to Pint* 'V '*, P.ttjoI 22An

C<mtiC3C\3 :

rtfor to ti-.o^ TDI* lettor to PSTA d*ti»d April 30, 1069. We orprovc c,| e repair of pl.tta "v ", Tonel ns d<».*or'l1>«'! rmij ^oorteTitcc'. In i1>«-i»ti» 1 rltroupj)

j i i.cl u_»iv<i ati-ociiud co t_Uu PlA'i letter.

'•'cry truly your a.

cc : Hi. L. wkW*. FIm"'-.

NIST NCSTAR 1-1 A, WTC Investigation 469
Appendix G

{PDM

PITTSBURGH-DES MOINES STEEL COMPANY

April JO, 10G0

Tl)o Port of K«w York Authority

GO Church Rtreot

Uev York, Now York 10007

Attention: Kr. R. B. Uouti

Subject: Tho Sfcrld Trsdo Ccntor

Contract VTC-313.00

PCK Contract 17072 & 17150

rtopaira to pinto V* Pnnol 224B

Gentlcaon

:

Vto aro eondinc you for your record and approval one

(1) copy oheotf? 1 to r. inclusive covoring the repair

proceduro for repairing a crack that developed In Pinto

VH Panel 224B.

This repair was nado In accordanco with tho "Invoratlrjatton and Repair of Laminations and Other Discontinuities"

da tod :*arch 19, 10G5. They vore ?,itftC3r.!cd by your Inspector

ttr. Davo Co f for 7.

r-len*jo nond uo a letter of approval for our records.

Very truly youra,

PITTSBURGH Dv-t> BstiifSiS $TZ£L C«i?ilFTjH. H. Pish

Frojc-ei cTanscer

?IM?:Iosh Skillins-Hello-Chr iotiBneen-P.cbortnoa Tisiuccn Realty & Cocctr. Co.

230 rork Avenuo 13 th Plocr, 30 Church St.

How York, i'tcv York 10007 IJow York, How York 10007

--^/-^^•Attcntlon

:

a. M N I V E R S A R V

llr. Janes Vhltn

Plua one copy of

pvocodure

.Attn: Er, !i. Geratcan

470 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

NISTNCSTAR 1-1A, WTC Investigate 471
Appendix G

472 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Contract 1713S Col. 224B £ ,VR- 4-25-G9

Procedure to Repair Crack on P^ . VR -FY 50 Cor ten B }IT f?74D047

(1) Remove Pl by"(either by burning or arc air gouge) grind any

remaining weld from this area.

(2) Preheat area at least 6" on either side of crack to 200°F.

Check with tempil stick.

(3) Gouge Area "A" to 1 1/4" depth, MT sides to make certain

that there are no defects.

<-j) Weld approx. 1" of area "A" using E8016-C1 (G7-49) or Arcos

72 (67-43)

(5) Turn section over and gouge area "B" , MT to make certain no defects are present.

(6) Complete welding in area "B".

(7) Turn section &nd complete Area "A".

(8) Cover with asbestos and let slow cool

(9) Check completed weld with ultrasonic inspection.

(10) Fit new £ replacement for "by"

(11) Reweld £, by as previously welded except as shown on Section B.B.

IMPORTANT

(1) Maintain preheat and mterpass.

(2) m. T. every 1/4" layer of wfelo in areas "A" and "B".

(3) All operations to be witnessed by Southern Inspector Agency

Inspector and to be documented.

NISTNCSTAR 1-1A, WTC Investigation 473
Appendix G

Juno 9, 1969

Port of New York Authority

OffJca of tho Construction Manager

30 Church Street Nev York, Nev Tort 10007

Attention: Mr. H. M. Monti

Reference: The Vorld Trade Center

Contract 'JTC-213.O0, POM

Repair of Plates c£, Panfll 130B; V

L Panel 139B

C-entlcwen:

P1c*bo reffT to the POM letter to PNYA dated May 23, 1969. The UT reports

attached to the PPM letter are sufficient to aJlov us to approve „he referenced

rcpsiro.

Very truly youre. SWIXINC, tlELLE, CHRISTIANSEN , 60DSRTSON

Ja^o «*hics

cc: Mesaro. L. ?nld. PNYA

U. Pleh. PDM

474 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

PITTSGURGH-DES MOINES STEEL COMPANY

The Port of Nop York Authority

30 Cliurcb Street

Hew Yorfc, Ifo^v Tort 10007

Attention : Br, P. . 11. Konti

Reference.I The 5orld Trndn

GoatlGDoa

:

2ofercncc to SIICR letter of Kay 16, 1009 to_2Ir . 5. Zi. Llonti approving per repair proc<?'Juro to plates , Panol

130D ana Plato V Panel - 139B contigent upon receipt of our JET roporto.

TTo are encloelac for your rocord one (1) copy of our HUT reports Ghseto l?cs. T~l and T-2.

Unlocu wo hear from you we tfill aasuiia that VUIej nul;~

Jcct uatter io ?inollzod.

Hty 23, lSo"-

Contract FTC-2 13. CO

PDM Contract 17078 & 17133

Repair of Plato IX Pscol - 1303

Repair cf Plato V L Panel - 1333

Very truly yours,

H. li. Ff-.eb Project flanaijer

ICI7tk3b

Sac.

cc ;> JuT. Janes V/ulte/plua one (1) copy

lir. a. Gorstnr.n

ANMIVERSAHY

NISTNCSTAR 1-1A, WTC Investigation 475
Appendix G

CONTRACT _ MATERIAL r TJUCKKESjf

DHAWiKG

Piusbur5*h-Des Moines Steel Company

ULTRASCXXC REPORT FORM

UI.lt

_ / '//. & . /^>0 & EQUIPMENT u ^KsTr/-/

& 7/6-

SURFACE FINISH ^

PIECE b'ARK Ut. ULTRASONIC PROCEDURE USED /!-tt>-, t a ij> METHOD USED Qru -T^oT

TECHNIQUE USED u t r-

,

PERSONNEL QUAL1E1 CAT I ONS ,7 2£Jj2

SEARCH UNIT

FREQUENCY - SIZE 2 CALIBRATION BLOCK _jry_,

C0UP1.AKT

BASIC SEN'S IT I V I TV ^.(T <a^-/-~ Wjv£>

WITNESSED BY ,<? <?/7/:~ J? <z > OPERATOR ^£j5. frf^y 77*

DATE V- 7- / ~7

SKETCH

fb Carets w/?i Too

SIDE \/i<>*J

KM ,0 /* //... -/

cf<£> /Jrr c'/T; ^ c/--'^r: r^:

476 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKILLING, HELLE, CHRISTIANSEN. R( BERTSON

CUmxulltn^StttictV'tii and ('iVif J- »s:r»uv»« J'jit V»* hja\ \y« Yt-iifc; \ \ M«>J" • \Ju \S~-J

foJtii H SfaHinjj iMa / llW/«- \ ( firiv/wii.,-., j

, ( K..l, if»,.„

t - HU.,'U<tft

I I.,- J.I 1 \\ ,t,fJ„.,W,o.| M^r 10, 1969

Port of Yor^ '.nfsority

Office of the Construction Manager

30 Oiurch Street New York, New York

Attention: Mr. 5. M. "ont

1

Reference: The '-'orld Trade Center Contract VTC-213. i'U. VUA

ic-poic of Plate "af ", Panel 412B

Cent Ur..«f.

T. Ue ayvrov* tbo repair of r>).-ite uf ' no ducvtttt-r-^'nt *>•* rht> PDM procedure thcor doted 3- 28-69 and it test report cLatec 'J-2V-69 , both attached to cliu 1 OF lotttr

to T>:.TA dat^d "*nrcti 31. 1969. Voile no UT report Is furnished to docuaeat thi

CTT check sectioned in the PD* repair procedure, no-ac la required for Laataations not cr.ccedtoc \h inchea In depth, per the PTW approved procedure "Investisations

and impair of Laainatioos orvd other Iilecooticultlec" dited (larch 19, 1969.

Very truly yours.

rLr • 3. fLsh, fUM

ifr. D. Caffery, SIC (Houston)

JV:lc

NISTNCSTAR 1-1A, WTC Investigation 477
Appendix G

SKILLING. HELLE. CHRISTIAN S EN. ROBERTSON

CutisuttiUa Stim fi,/W ,in,l('i\ii Vn^irnvn 2~tt J'.i.i \(i-m« . \,\r V. ii. \ ^ |i«U' \J„ 'J S\-

W ... •,. \ n>im i-i

' -ttUlClrlt*

)<.»•. J..' I }l ,..(i,j„ t.,-<in

»--—.-#•* ' 1 Key 16, 196D

Port of tf«s» YorK A»ittority

Office til L..* Coc« t rsct ioo Mjna<jor 30 Chores Street

'.lev Tor'*., ?;cv tark

AttCOtLon: ?'r, Tt. fS. Voatt

ileforencc: Tk« iJoriJ Trade Onior

Contract ..1C-213.O0,

Placicft rei'^r to tucr ^t*' l«tt«r to rW'A dated April ?1. TJir Ti:'r> uT nvp-ort revised I-Vj—G? repori_lny rewult* of UT t*"ts on r-pnirn to )>lnte V, I'*nol "»3V3, to mif i icltTit to ollou us to approve the repairs te tit* cuMece plAto.

v»»ry truly /ours,

SKILLDi'.. . ilKU-t, OlSISTlANStH, SnfiKkTSOf,'

Janao White

cc< ^r > f«l«i» Mr. ii. Fish, rm

Mr. :•. OiJrory, SlsCQoustoo)

JUtlC

478 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

/ y

P1TT5EUBGH-DE5 MOINES STEEL COMPANY

April 21, 1969

The Port of New York Authority

30 Church Street

New York, New York 10007

Attention: Mr. R. M. MOnti

The '^'orld Trade Center

Contract WTC-213.00

PDM Contract 17073 £. 17138

Repair of Plate "b" Panel-3398

Gent leme n

:

In coojpliance with your reque-Jt, in your letter of

March 20, 1969, that we submit revised copies of NOT re- ports we axe sending you for your record and approval

one (1) copy of Sketch-SK-4 Sheet 5 revised March 19, 1969.

The purpose of this report was to show that are.-xs in

question were satisfactorily C.T. inspected after repairs

were Bade and witnessed by your inspector Dave Caffery

Please advise us by letter of your approval.

Very truly yours)

PITTSBURGH DES .MOINES STEEL COMPANY

H. M. Fish

~Si-J fxy,fir~*di S/lb/b't Project Manager

i /

• HMF:ksh

Skillir.g-Helle-Cnristiansen-Robertson Tishman Realty s, Constr. Co. 230 Park Avenue 11th Floor, 30 Church ST.

New York, New York 1O0O7 New York, Ne-.v York 10007

Attn: .Mr. Janes White Attn: Mr. M. Qersttnnn.

NISTNCSTAR 1-1A. WTC Investigation 479
Appendix G

jc-iu^piafg"l\-Ded Koines Steel Company

ULTRASONIC REPORT FORM

ULR

CONTRACT 17)36 339B EQUIPMENT I'SICS-M

»! AT ETil A L . KY 43 THICKNESS 3" DRAWING

SEARCH UNIT Compression

SURFACE FINISH , s^poth

PIECE ilARK n P\,-\%c. - 3393

ULTRASONIC PROCEDURE USED . ASTM 435

METHOD USED Contort

TECHNIQUE USED ^alr.e Hc hc

FREQUENCY - SIZE V? ?. .f

> . - \ " Qj,'r., CALIBRATION BLOCK , 1W . COUPLAKT Wlwloif

BASIC 5ENSIT1 VI TV 11,-vc-k «of. WW

WITNESSED BY ^ P. C.-xf^./y

PERSONNEL QUALIFICATIONS SNT level 2 OPERATOR R. S. C

DATE 3- ^ - r->9 Revised Report: 3- 19-<j0 C. Vignc

SKETCH

b' Platos N.~S. 4 I*. S, U.T. Inspected as noted on sketch SK-4 shown below.

-M6""inc5ications seen 'on".-. the macr.ine at above? nro-cdurc icvol.

.Or X-t r'A JKtp. /i?M5 SHc^tJ Be^ot-J

I p.

Hr. ,-/©« 6/'/jS'M

480 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SK i LI INS, HELLE, CHRISTIANS EN, ROBERTSON

Corwuttuig Structural and Civil Engineers • 230 Park Avenue, NW York, N. Y. 10017 • Mo. 9-SS74

/oiin 8 SfcSliwg • Httgc I Hclic • John V. Christ-anscn Leslie E. Roberiion

July 15, 1971 ,„ File: UTC-230C UVn-JLlW,,

J^Ilf"»213C Cenntiar.lt jOC Harold L. Worihingicn

Joseph F. Joclion

Port cf New York Authority

Office of the Construction Manager

30 Church Street Kcw York, New York 10007

Attentions Mr. R. M. Monti, Construction Manager

Reference: The World Trade Center

Contract OTC-250.00, KKE

Contract V.TC-213.00, PEW

Repair of Column j27B

Reference No. 1, SHCR Drawing 2AB2-15, Detail 26 Reference No. 2, FDM Shop Drawings MP610, MP611

Gentlemen:

Please refer to Sl-lCR's May 21 and July 15, 1971 letters to PNYA transmitting

repair procedure information for Column 327B. UT evaluation of the repair

work required in the SHCR document "Repair Procedure, Column 327B, Elev.

372' -6"(*)'* is reported in G5K UT report sheets 1 through 6 of 6 dated 7/6/71.

G6H report is enclosed with this letter. G$H sheets 1 and 2 show that the 6'(+) length of repair veld between plates "a" and "c" is acceptable. Sheets

3 ar.d 4 show the extent of a crack which could not be completely removed at Elevation 372'*6"(±) during the repair to the edge of plate "d" and the fractured partial penetration weld. Sheets 5 and 6 shew the extent {1>j inches

long; 2 to 2k inches deep) cf a defect found in the horizontal repair weld

to plate "d" at Elevation 37S'-6'*(±).

Subsequent tc the above uT testing, the south 2/3 width of the CP weld between

plates "d" and "b" (EZ to F2) was repaired as follows:

1. Provide preheat temperature cf 2uD-250°F by use of radiant heaters

at Tepair line.

2. Arcair gouge defective metal within central 1/3 width cf column. (Discussion with workmen revealed that surface to one inch deep was sound,

that one inch deep to backup bar was extremely porous with cracks running

from defective weld metal into the base metal vertically for various short

lengths)

.

* o • i A T *. HVItt, B. J. WM/TA, I « . * CCMAMD W. CNAyMCR L C ( N T ( L.. WtOtHO *AVt p. * . rDiri, a. J. A •* « • m I A c r>Ak< HoriuiHO" villa * t« i«

* a N t « •» ». t I v »• »- »»t»»B»*T

,I«T a.. *««a* hick, 1 1 • . tttao {..ill A. kANDUVKV «»«SLO O "Oil

WILL, AM O. WAAO IOVaAO WOb'CCPK

• SATVLI O I

NISTNCSTAR 1-1A, WTC Investigation 481
Appendix G

SKILLIN 6, H£LL£, CHRISTIANSEN. ROBERTSON

Port of New York Authority

Attn: Mr. R. M. Monti - 2 - July 15, 1971

• 3. Allow column to cool at end of work day using asbestos blanket capping

for slow cool

.

4. Elevate temperature at begianing of work day.

5. Perform central 1/3 column width repair veld using E7D18 electrodes.

6. Slow cool column at end of work day.

7. Upon completion of work at central 1/3 width, repeat repair sequence

of steps 1 through 6 above for south 1/3 length.

8. Upon completion of repair of entire 23 inches of defective weld, Elevation 372'-6"(i), UT entire width of plate "b" and "d" in repair area.

It should be noted that the repair excavation was of the order of two (2) inches

wide at the root, extending above the shop backup bar and roughly 1/2 inch maxi- mum into the 1-3/4 inch diaphragm plate CP veld. The workmen reported miniswra

fusion to the backup b3r, very spongy weld metal, and numerous cracks in the

base metal running vertical in the plate (normal to the axis of the horizontal CP weld). The shop weld was made in accord with PDM procedure 67-48, a xerox copy of which is attached to this letter.

Also attached to this letter, please find the G5H UT report (one sheet) dated

7/15/71. This report shows that the defect reported at Elevation 378 , -6"(i)

in the GfiH 7/6/71 report (Repair 1 in the 7/15/71 report) has been removed and

the repair weld is UT acceptable. The 7/15/71 G&H report also shows that the repair to the defective shop weld at Elevation 372'-6"(±) is acceptable as welded.

Very truly yours,

SKILLING, HELLE, CHRISTIANSEN, ROBERTSON

James White

cc: Messrs. M. P. Levy, PNYA

L. S. Feld, PNYA Attachment #1 GSH UT report dated 7/6/71, pages 1-6

Attachment #2 PCM Weld Procedure 67-48 dated April 6, 1968

Attachment #3 G$H UT report dated 7/15/71

EJW/is

LER

482 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

NISTNCSTAR 1-1 A, WTC Investigation

483
Appendix G

S KILLING - HELLE - C HRI STI AN S UN - ROBERTSON

CpmuUiitsStiuclutcl tint Civil' Engineers « 2 >0 Pj / ,A «"•»«*. >Vr(»' ' YorJt, N.. V. (00.1? • Mir. 9-:SS7-l

/o/i ii /). SkilUnu • Itcl^c I MW/c • /r>/m \' CJimiumoi • Leslie E Rtthfrlsim

ComuJtu'tll

for; of YorV Authority

Of'Jcr of fhfl Cnnr.tnirrlfin Vnmppr

:.ci: lor*. York 10007

Ln«*itinted ;vl.it';? "A" Srawln;; NJ'IOo

"nut 1 C.-'On :

Pl^.ifif refer to r'fi iT)'-* Jcttcr tfntrri Joito 11, 19<>3 r*'f o;-r I-v. to lft«st «i »c0 plarcc "4' f>Hov-m on nl*or> 'Jrrtvtnr, ':P'06. The rrpMr proro^tirr1 st'-tcd I r. the nr. t.icb^rnr. to the lotrcr nixl ntiovn in H.o l'Titi iV.oirJi J;.tc,( .l.iinii 10. 1'J/V!! in spurm-M . Thj>so lonlnfit loiiu •-crc il 1 r)fi>vi>r>'-! r.(\^r rhc ;vI.-jt<-» j'-rr- V(»li'n.l intfi n cc::.p 1 nt rt column p-Tni] Tnn'.i' ] v .

Very truly yonrti.

SKILLJrft. MTLLr, CIllJE.STT^riST."1 .', i»(Hl KRT«50?-

'.c::o rs . L . r . cia - I'M'

A

'Jr,h - Ki'l w a * mi * p I - r.*

. p * ' o » * r » rmiti hcuti

OSIMT C w * p pj i * a s » r • N| «'f » . • O C I »

484 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

October 7, 1968

Poit of Nev York Authority

Office of the Construction Manager

30 Church Straec - JUxjm 1119

!Jaw Tor*. New York 1O007

Attention Hr, s, H, h'onr:i

Reference: The World Trade Center

contract wrc-213.00, Pit t»bu.r?.U-D«9 Moln»9

Repair of Hloto for Panel 209A Geotleaem

Pleaae refer to the PDH letter dated September 30, 1968, referring to veld repair procedure) for plate V** for ponol 209A. Wo Imve reviewed this

procedure by telephone with Hr, H. H. Fish of PtJM. end opprovo Che PDM

repair procedure.

Very truly youre

,

SKILUN'C. GTLLE, CHRISTIANSEN, ROBERTSON

Jaaee White

JM:o

cc: Uesere. L. S. Peld, PNYA

H. M. Pieh, PDM

NISTNCSTAR 1-1A, WTC Investigation 485
Appendix G

Ets*i»XEf»a I rABWlCATOSS (CONBIKUCTOXiS

PITTSBURGH - DES MOINES STEEL. COMPANY

Skilling-Hella-Chri8ti«nean-Roberto on 230 Park Avenue

Hew York, Hev Tork 1000?

Attentlom Kr. Jaaee White

Refe-renees Th« Korld ?r=is C=tsr

Dear Hr. Vhite:

Enclosed ie one (1) copy of the Weld Procedure that was inadvertently not sent to ycu.

Pleaee notcfy ds by letter of your approval of this

repair procedure.

October h, 1966

Contract VTC-P13-00

P3DM Contract 17078 St 17138

Very truly ycum

,

PITTSBURG H-rES MOLHES STEEL OGKPAKT

H. K. Fioh

Project Manager

Enclosure

ANNIVERSARY

486 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

0C9/

/ZP7X~~, £s7J.?^S lo&C

Cot. ~Rc?A A ° 7' te*<°-i*

- .t ^

oy&c /e?*m

7i{S£> gsr&V:. V'.-' 7

7>'r

flews r'lATer h/A$> gu^c^ ov uy/?o*/c i/Att? y? . _

jBo/ZNfo:,') .c^/? ..>//)$ .P.&.&.&I.e.e.b , a<vz> t</<5~£ BAC^.oa/. "7.o. /yiAlA/„

Plat*?-, a&oi/s c g t>u#&. fiatc? \y/t s r/s&A/ Y/?/iy&.z>„

NISTNCSTAR 1-1A, WTC Investigation 487
Appendix G—/

PITTSBURGH-DIES MOIIMCS STEEL COMPANY

September 30, 19ui3

Mir. R. M. Moot i. Construction Manager

aOcs 1119

The Port of New Yotk authority

30 Church Street

Hevt V'orK; f.'ew York ICO'"'?

Contract KTC-2i-'-.00

PfSM Contract I ,', IVIjxJ

Gcrit It'Ciy i! :

vc arc t ubnii I t iny i or opprov.il two (~) cop i as of o^r ./clo prccti-'urc fur rcpoli iaij plate V on panel 20>A which w**s Lrtt.Uvrr tani iy cut y irtencs ^iiort.

This panel it detailed cn at ^ ftiii^.s :-'iF6-t2 Jnd iSP64.'i.

P3ci>s<7 hive the cnoinc«i rwiefy us by letter ci hio approval of thin repair procedure.

Very truly your 3 ,

PirrSbURGH-Ds.a .'-JOI^o STC£L COMPANY

Proiect h-if»,.iijcr

HMFrksh

enclosure

c 1 ^^KLllir.9-l!^llc-G-triEtianson-.Rob<;rvson

TtEhrnct-n Realty and Construction Catnpany

A f\J M I V E R S A R Y

488 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

S KILLING, HELLE. CHRISTIANSEN, ROBERTSON

Cvfisuttins Structural a,ul Ciiil fvN-ttirrn 2%C IV/t ,\w««r. fv'ev Vnrfc. N. V. f«OJ; - ,\tu «WKN

t<**B.m,nK • IMF t mitc him V Chn«im U*t Rojwriw..

W jiiif \ Mi<-<.ri

CoMtt/ftttltl October lb, l«6& iu^L v 0,ii„„ {iw

/osrp)i F fe<-*>f>n

Tort cf ;:«w York Authority

Office of tha Construction Kon«j.or

JU :m 1119, 30 CIjutco Street He/ York, 8C«v tor'f. 10007

Attcntlcct "rir. X. Ksati

toicrcrco: 7L« Vcrld Tridc Cs^Cir Contrast UTC-213, i'itcabuCHir-^i- t*~l=*= StitC? Cotwr«t>v

VKjldlnp. of torc.er r«n«ti» 1C5». W>A

C'iCtlcaBS l

C« have reviewsd tin l'fl« let tor dated October 13, 29(£ J to vbich Is attached

oc outlln* of repairs PDM propose* tc r«rforo. aoc 3t*tic£ the Actual veld

netel plxcei in cotrior paaele 100A, 200A, 30CA end 40OA fcr Tover "A". Th&se ere evtliaed in four (e) tt.ro* p«£c letter*, oaa for each conwr panel.

The letters are dated Octcbor 10, 1960, ei£Bod by Xr. C'e letter, PLM CMof of Quollty Control, arxi *r* addresacd to Mr. Fieh, TtVH Project Kanager. Butt vcldH in eighteen ecparate location* require repair, etc! «r-oout to a totel

lco* th of u=ld slightly la exceoe of 22 feet.

Also actocted to tlx* PX5< letter lis a PDH procedural dravio* ohwics, -etop by

atop, all <iotalle of tbo required repair vork.

5'J.CZ epprenrce in entirety the projveoed nctfcedc and specific location* of -— -

;

: - _.- i= !*Ta' ?<5Tt*r.

Very truly ^curo.

SXILLHiC, llCiE, DlEISTTAl.'SEN, E.O0EOTSOM

Jcc^ca irhitc

ce: Lkjsare. M. P. V*vy, P2ITA

«, C. UorLend. PJJYA

- « *» Y ft «««» J O • r K

!'.. H. ?tjjb, VZ>» r«*iilt IfNCUfK Holton & Caff rev, SIS t>. >»» .,«..,» ». •»»«*« i • a a ~»«-i«.o>o« «uiLD>«a. ».«*1rrt*, , * «

NISTNCSTAR 1-1A, WTC Investigation 489
Appendix G

PITTS8UF1GH-DES MOINES STEEL COJVJPASN3V

KfVd iif » » « ' tint** « f NNO", w**tst * *»«-<if*#-r. «•*«,*> ^» IVK*H

Octcbor IS, 1968

The port of New Xcrk Authority

30 Church St root Hew ?orkf Now *ork 2000?

Attention j «r« &, H. Moati

P.cfcron;;^ j Xba World Traos Center

Ccntrart Vrc-213.CQ

PUi Coalreet 17075 it 17136

We crc sending you for approval two (2) copieo of certified

Veld report pert sifting to Parole 100A, 200A, 20QA and L00A» All

of these panels *ith the sxteptioa or J0©A hac ocas of the velda

made usln- the vrcng electrode which will rcquiro rcpairi«£»

We have reviewed these sheets with Jr. Jaaee' White in our

office October lit, 1J/60 ana have noted on the left hand side cf

the 3heete the repair action v. J lie h will t« required.

He arc also Including two (2) reproducible copiee of Pa^o 1 ohcuinc the weld procedure for repairing tboae paacle.

Plcaae advise uj by letter of your acceptance of thie repair

procedure

»

Very truly yours,

PXFTiSiiteiia-iteS h'OIW.S STEEL C&FAHZ

JU fu yiah

Project Kena^er

KKfjtoh

Enclosure —

»

) j r«^» SK111S ng»Helle~Chriotiaacea»ltobert-eon Tichman Hoalty & Constr. Co.

1 / r«—' « _.j30 P^rk Avcxao Uth Floor, 30 Church street

* nev Jfork, h'ew lor* 10007 Hew YorJs, 2*ow lor* 100O7 iiMIVERSAHY

Attention* nr. Jeiieo White Attention Vx* Oersiaan

plus con copy of weld report end Pace 1

490 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

8p5j§|Ss THE PORT OF Ni YORK AUTHORITY

ITl E^iSt Avcnue-«>5»h Street, iscw ¥«>!, N.V. 10011

M^Jt „: Levy, r>*«-i. P«»f>«i«fr Con»:»«*tM-fl D.»<>^>«

^ M .v. Coi in. *uius" Trf«plMiK"aia

World Trade Department

Guy f. "lOlZOli, DirrCTOr RiChud C Sullivan, D.<n:iot. Ihc ivoild In*- O nicr A. - ... :i

September 21, 1067

Saanray rociiic Corporation

11323 souta Alexia Street

laa Armies, California UOD02

itttatica: He. *• £. Cthaoa

lis: Ei£ tlOSU) Tti/Jir CZKTai - Contract ~?C-217.00 - Incpectioa Slsquirasaats for Steal in Scotland

Ccatieuco:

Rcfcrenco Is cuidc to your lottcr to Mr. CP. Zavy,

dated Scpcccdjar 5, i?57 reenrdiu^ subject etoal requirements.

Your statceaasfc that Stauroy die not and will not

accept as a oonoral rule length auitipies otacr tb*a ordered' t appaar; to ba a laattcr bct>coa ye-u and your stcoi supplier.

Super ictcaJentc, I--;., in tiair ir.spcc.tica v-ill, oC coursa, advise

of any varictinas, not only £roa your crJcvs, but froa tha

r^uircd ciiecii'icctiona. I believe the aaxlsaa auribcr of shop aplicoo,

that is, at every fioor threa (2) feet aboro floor lino, is covered'

by Clause J'o. 3C3.200 of tha space. Yiur previous request to splica

every cic-tcoa (10) fiat '.as approved contingect on your oubesiaslon o£ details oa handling -.aid interference wich connection detail aaterial.

Yeor letter states on ci^e ccrulitions, that blo-outa exceeding

1/6" la depth, •b.irc asterisued cn your purchase orders, '-."ill ba repaired

voi^lzi". and grinding ond that ca all other plate blo-outo exceeding

1/A'' in depth, will bo repaired by valding and grinding. Please bo

advised as follows:

1. I fcsvo no dafinico Icr.o./lrdje of your purpose or ground

rules used in caccblisain^ these ajtcrioUcd ituna in

ye-ur purchase ordern.

2. Clause Ko. 2C3.201 of opec requites all bio.-cuts osccodir.3 l/S to bo repaired by -sldins and grinding.

3. 'fhiizccgra, it appears that you ara increasing Cl»e ello.ablo talerenei required by the specif icatioaj,

which X canr.ct permit without farther detailed

explanation iron you.

NIST NCSTAR 1-1 A, WTC Investigation 491
Appendix G

2-

Pcndir^ ra=ci'it of further inforaaCion froa you," Csrcp Juporiatcndc-.-.ts, Inc., will continue to be covcmod by

^rcsaac contract syacif i;atior.j.

ii--ciroly 4

S. 21. Monti

Construction Manager

Iho ..orlu" T;-a«2o Center

cc: Sicasra. J, Ecdlor (race), L\ Cosia-^o, J. i-hltc X5I2CS)

-..-/art. vr/att.

492 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Oetobor 16. 1969

Arc ade &ulldio3

St. Louia, Missouri 63101

Attention: Mr. Robert D. Boy

Rei Tbe World Trade Center - Contract

WTC-221.00 » Lacledo Autooatlc

C02 Heidln^

Caotlonoct

Plceae refer to tho Laclede lector tt> SHCE, doted icpicaber 6, l*oj, and toe SBCR latter CO POJfiA, dated October t>

,

1969, on which you wore copied.

your roquost co use tho Hobart autocade C02 welding

cqulpxsct eod voiding procedure submitted in your latter or Bspteabar 8, 1969, is granted provided that production veldlnj on

Contract lvrc-221.00 performed by use of tils equipaeot meets tbe requirements of the coatract documents oou there vlli be do additional cost to tbe Authority.

If at arty time welding perfornc-d by thie equiptnont should

fail to satisfy tho contract requircEtanta , thla permission nill be

withdrawn and cha cost of ooy ropolr vorU. will bo to Lacledo'e account.

Very truly youro.

a. M. riootl Construction Manager

JlX:rzifl The World Trode Center

Copy to: Kossrs. U.C. Borland „> . J. White (SECR)

M ' ACC -

NISTNCSTAR 1-1A, WTC Investigation 493
Appendix G

SHILLING. HELLE, CHRISTIANSEN, ROBERTSON

ComuHihlj Structural end Civ8 Zttgmcvn • 2~>Q Park A\tiivc. No* YTMk, Is? V 100!? • Mu. *?-6S7-J

john B Skilling • th-Igc J. I Idle • fchn V. Chnstitmsen • Lfsfie £. Robertson

Woi no A Btr»xi

Cciiruffuufi

Poxt of New York Authority

Office of CoE8tructlc»,i r-an.iger

)0 Church Street

Nev York, Nev York

Art-ifSies: Hr. *- B. Monti

Reference: The World T/Tade Center

Contract WTC-221-DO, Laclede

Autocratic 002 welding

Gentlemen:

October 6, 1969

File: W7C-221C

Please refer to the Laclede letter to SHCR dated September 8, 1969. We reccr-ttsrui ?H>a approve the use of this automatic equipment. While the teata

w«re not standard AWS tests, and tne tee; »ssrplcs vsre run at Troy. Ohio by

Pobart Bros, instead of by Laclede, the teat values clearly exceed 2/3 of

the ttlnioun specified tensile strength of the baae octal for longitudinal

shear and 7/8 of the niniaua specified tensile strength of the baae »etal

fcr transverse sheer.

On Friday, September 26, 1969, Laclede was in the process of performing

test runs and final adjusttnsn-; to the equipment. Upo= completion of tria.1 operations by Laclede, SUCK and PT1. will maintain coc'.ioual day to day sur- veillance of the quality of productlcn welda perforoid by uae of the Bobart

eutoiaatlc C02 welding equipoent.

Very truly yours,

James White

JW :ans tc Mr. L. S. Feld

R. Bay, Laclede

r«m » . igti{>

VifAH« .of^'f «|Nf • • D O t * • a tvt • . * s fflip

* 4 .rill j%

4. OB«**t» i v*io*<«a

.if .».£ r.iiiMi, (ftltl'ii 1.1 »

IC.#»9I UriM

* t *v * * . c o *• * » c « • * • c »,»».*i»ic>©»* * v * *. o » * ^ »«*>ti» nr'' a » »• i « t • .h » o , o ,

494 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

C'f //<isrw» ty/c/ September 8,'.1969

Mr. Jaraes White

Ski 11 ing-llc 1 lc-Chr ist ianscu-RohpTtc^.;.

250 rarh Avenue

New York, Hew York. 10017

D=~r Mr. While

:

Approval^ - Automatic Arc Waidjnfi

In accordance with Paragraph AO5.3O0, World Trade Center Contract

WTC ^1.00, formal request is herewith made for the use of CG7

Automatic Gas Metal Uirc Feed - Arc Welding Equipment for use in

making continuous 3/16 inch and larger fillet welds on chord plates.

The chord plates arc on the bottom, chord of trusses and on the cop

and bottom chords of bridging trusses required for the project.

The equipment uses Hobcrt i?RC-750, 750 a^p Constant Voltage. 100

Per Cent Duty Cycle Power Source v/ith Hoba; c £A0-23 Automatic

Panels having a VJire Feed Motor, Head and £jf?225 Guns. Hcbart

2CMS-9A Electronic Seam Trackers will be used and Hobart 0377450

Nczzels

.

Attached herewith is Welding Procedure numbered C-4713-A prepared

by the Hobart Brothers Company and dated 8/26/69 pertaining to the

equipment. Also attached are proof tests on samples of the Laclede

arterial which was sent to Hobart and welded with the eqa ipaent at

Troy, Ohio. The material was returned to Laclede Steel Company

and tests were made at the St. Louis Testing Laboratory, St. Louis,

Missouri. The test samples are available for inspection at the

St. Lvwls Office, ^ersorr.el which will use this equipment have

already been certified for Automatic Gas Metal, Wire Feed - Arc

Welding.

Since the new equipment is to be installed this next week, we respectfully request an early approval so that ve msy proceed

1

-

NISTNCSTAR 1-1A, WTC Investigation 495
Skilling-llelle-Chriotiansen-JlobertEOQ Page- 2

with the plan to utilize this new equipment to reduce the large

backlog of arc welding which is now at our shop. If there are

any questions, please contact the writer.

Yours v,ry truly,

lacle:*. steel company

\obert *>. Bay (j

Director of

Technical Services

Project Coordinator

CC: Mr. Wayne C. Brewer, SHCR

*r. Le3ter Feld, PONYA

Mr. Al Gutteotag,_Ti$hman

NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

5KILLIN6 - HELLE - CHRISTIANSEN - ROBERTSON

CoujaffMtjj Sfiurturo/ tfnil C:\iJ Kngj'ntv/s • 250 i'.ni Avenue, jYcv Vi»ifc. N V IWH~ • ,\f« OSS'

4

Jc/<--t J). Skitiing ' llcl^e I llclic • Jc'/jm V Cht&tkm*cn • I «•»/» K, Hobrr<.«>n

December 15, 1967 t: »'f*u.

Port of l*cw York Authority

Office of t!-c Construction

Maosger - P.ooci 1119

30 Church Street

Kcw York, New York 1C007

Attention: Mr. R. K. .Monti, Construction Manager

Reference: The votlc Trade Centor Contract WTC-21A.0C, Pacific Car C Foundry

Diapbraga Plates, u e lde C5 and ('7

Cent leoer i

Pacific Car i Foundry luis requested, and ShCR lias apprcvec, the elimination

of the cllppec: corucre cn stlffener platco oo cho-n in Sections b-b and

d-d. Sheet W-AS2-32, drawing Coon. C, and oquivuleni conditions. PC? intends

to install Checc platec in the "iadcer" aaeaobly prior to assembly vlth the "bed sheet." Where weld 05 ie interrupted by a stiffener plote, It shall

be thoroughly fused into Loth 6ides of the subject atiffcaer place. Should

veld 07 be interrupted by a Gtlffcocr plate, the stme requirement eppiicn.

Where the Drivings show a 3/6 inch fillet vcl<1 between the stiffener plate

and spandrel plate t4, this weld 0I13II be 7 inchea long 09 shown in the

Drev^ings. Where a full penetration weld ia required in the Cravings ,• or where PC? electa co coc 3 fulJ penetration veld, the place shall be beveled

and the weld Bholi extend full leogth along the spandrel between the two tl

r>J.«r-r

All tho above changes chall be clearly illustrated io the ohop drawings.

Since the ebeve procedures have been approved at PCF'g request, it is understood that the cdoptioc of theee procedures will not result in edditlor.al coot to PIIYA

.

Very truly yours,

SK.:LLIHC-lti:Ll.fc:-C!)RlSTLAjNSKN'-H£H'.L"KTSQN

Jones V.1iltc ««<« . .»»-»•

JV : S t \i cc: nr. L. Tela. PUYA

Mr. R. Syaos, PC? »>«m><

Mr. A. Tarkohirc. S!1C?.-SZ ^7'*/.'.*'"

NISTNCSTAR 1-1A, WTC Investigation 497
Appendix G

e l u t . CHRISTIANSEN. ROBERTSON

^t$lMk..,\wm,v. Nrv W.K V. jijfjjr .\f»,.<m-*

|(,/m V Chmtni!>.\i.n

May 26, 1969

\\ am \ Hirx,,;

Port of Jtew Tork. Axuhority

Of flea of tbe Construct Joa Hanagcr

30 Church Street

.Hew Tcrk* Uesr Tork

Attonttoa: Hr. R. H. Vonti

KefortuCR: Th« World Trade Cooter

Contract lflrC-214.00. PCF

Kcteri«.l Substitution* - Baara Scjt Anglca

C<ratlre<rai

Please rrfor to PCF letter <i;ted May 19, 1969. »c approve tha mm of

0*6X1 inci> en#Xe« in licru «f 15X6X7/8 inch angles for been ocat ty?*-0 7A40 through 7494. PCP cruet verify tluit no additional hole length rill tx re<;uirc<J, or provide re-s-lned bolt licto if nccoaoory , at zso coat to P5TA.

Very truly yxjora,

Jases W»it«

cc: Kr. I,. Fold, PKYA

Hx. 2. Ey^ca, PCP

bees Mr, A. Da rkobiT(i-8!iCK—SEATTLE

JW:1

' * * t m

498 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

^aclfic Car and Foundry Company

O iOUT" HUDSON > SEATTLE WASnlNOTON 0613J-RO

May 19, 1969 D-666 PCF f?S-14

Skilling Helle Chrisciansen Robertson

Consulting Structural and Civil Engineere230 Park Avenue

Neiw York, New York 1001?

Attention: Mr. Jomes White

Reference: World Trade Center Contract WTC 214.00

PCF Project D-666

Subject: Material Substitutions

Gentlemen:

On beam seat types 7440 through 7494, the 8" x 6" x 7/8" angles

specified on design cravings are not iaaediately available. We

are therefore, using 8" x 6" x 1" angles for these beam scat

types oc tier 40-43 A. and S, 43-50 A, 74-77 A and B, and 77-80 A. No other dimensions or engineering details are being changed.

Ilcccic give us y-.'iir ppfTOV- ' t>i rMs substitution.

RCS : ca

cc: R. Monti (POtfYA) M. Cersttnan (TRCC)

A. Barkfihire (SHCR)

J. Davis (PCF)

Yours ve

R. C.-SiWes

Projecn Man

uly,

NISTNCSTAR 1-1 A, WTC Investigation

499
Appendix G

SKlLLtN G , HE LIE, CHRISTIANSEN, ROBERTSON

CoiiKultin" Structwtif «md Civil KMi-mccr* • ?;*» Park Avemn\ bleu* Yvtk. «V V J()0J" \Jw. *>J»5H

{aim ft.Sisittittg rMsrj llrfi*- V CkuMiiHH I ,.* K. Jlo/uvixm

Hay 2„ iSd9 f,j(,f>), I j,-ri.io>i

fort of Hcv Ycrfc Authority

Office of chti Ccn« traction tU>.onct-t 20 Church Street

New Yorlc, l«*cv York

Attention: Mr. P.. M. Ilonti

Eefercnee: Tl-.« V-"crld Trade Center

'

Contract W1C-214.GO, 1>CP iljituri^l DuJiaiitutioa

Cent le=cn;

Plaxeo refer to TCF letter #P-1U2 Jctod April 4, 1965 ctt«chta£ cbecto i and

2 of 2 tillec '\Lntoriol Subotitutiooa".

All mutorial oubstttationa sbovn oa the tvo (2) o'ueett prepared by PCF arc

approved by SliCP..

Very truly y&ure,

SKILL1HC, liTULt, UiKIill/^;^;;, ;-^.£7:T'.- »«

Jft=ea White

cc: Kr. L. Feld,

;ir. E. Syaen, PC?

JVtlc

bec: Mr, A. Berkshire

»0»t »l t ||y,|<

"•"I » • rc<»*

"Otiii VH&ri t«nif 1 ' t. . W © t I I « * - f » H>*OkO 0 •Ctl

»;c-*«o r tot

500 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

stf^ucTuRAL aieti. division

Pacific Car and Foundry Company

J -.-..!. -«:«.-,:.u.' OC SOUTH HUOSON St ATTL f, WASHIN6TON 98134-RO 2-74^0 April 4, 1969 P-666 PCF 0P-2O2

The Port of Xew Ycrk Authority

111 Eighth Avenue - Rood 300 New fork. New York 10011

Attention! Mr. R. M. Monti

Reference: World Trade Center

Contract UTC 21'< f>0 PCP Project D-6

Subject: Material SubacJ

Ceotleaen:

We have eo fcr received ov irrlvcd at

the point in fabrication w § 1 to suit

the catorlala on hand.

IM placing the original 01 U I ^fc , wc had to cake allowances for cuttii \.^^ c obviously

attempted to hold these a cctlon of material uaeue that we u , e yield and

thickness aod lnsufflcicn ;ltutc materials hovlng yield and/or jn drawings,

we will be able to uoc tr and controL

problems which could be < 11 « e holding

oe cloee ae poosible to <

The 9ti«lc1;<s<2 iict shews a co make. Most of these changes ar Revision 1> approved by Messrs. Skilllng He-lie Chriatxanbuu - >er 25, 1968. Since eLl substitutions slightly increase either the thickness or the physical

properties specified on design drawings, wc do not anticipate any problem and are proceeding immediately on this basis. The only exceptions ere mechanical

floor unit Oil, which we downgraded 5 k.s.i. The ctill to»c report for this cmtcrt*l, heat 0L6799 (copy attached) gives physical properties above design requirements.

If you have any cocoents, please adviee us as soon as possible.

Venire very truly,

fUCSyoes, Project Manager

RCS:c»

Attachments

cc:^J. tfhitc (5HCR)

M. Ceratcan <TRCC)

NISTNCSTAR 1-1A, WTC Investigation 501
Appendix G

PACIFIC CAR AND FOUXDRY COMPANY Attachment to letter FCF 2P-202 Sheet 1 oi 2 MATERIAL SUBSTITUTIONS

Prod. Unit No. Eng. Fooel He. Material Location Material Specified or. Design Drawings

1156 A 457-53-30 FL 2 Col 1 and 2 FY ICC x 1 /4" FY

1157 A 206-52-49 PL 2 Col 1, 2 end 3 fy 100 x 1/4" FY

1172 A 212-56-53 PL 2 Col 1 FY 100 x 1/4" FY

1225 A 333-54-51 PL 1 Col 3 FY 55 x. 1 5/8" FY

1437 2 357-13-10 FL 1 Col 1 FY 55 x

•> 1/8" FY

144 6 B 303-13-10 PL 1 Col 3 FY 55 x 2 1/8" FY

1471 B 157-16-13 PL 1 Col 1 FY 50 x 2 1/16" FY

1472 B 103-16-13 PL 1 Coi 3 FY 50 x 2 1/16" FY

1515 B 239-13-10 PL 1 Col 1 end 2 FY 50 x 1 15/16" FY

1539 S 1.27-17-14 PL 1 Col 1 FY 5D x 2 11/16" n

109-14-11 PI* Col FY 4 5 x 2 i/B" FY

1611 E 316-17-1"!. PI- Col 1 FY 45 x 2 U/16" FY

1611 S 13B-17-14 PL 1 Col 1 FY 45 x 2 11/16" FY'

1617 3 321-13-10 PL i Col 2 »

j

Z 7/-Y*

161? £ 321-13-10 PL 1 Col • i FY 42 x 2 7/8" FY

1625 B 409-11-9 PL 1 Col 3 FY 65 x l" 7/16 x 24*1 n

Fi

92 A 100-50-52 Pi 1 Col 2 FY lOOx i/e" r

S3 ,\ 300-5B-6C PL ] Col 60 h 13/16" F"

502 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Material Substitutions

Attachncnt to PCt" letter 0P-2O2

Sheet 2 of 2

Prod. Unit No. Eng. Panel No. Material Location Material Specified on Uoslpa Drawings

lech .

98

116

120

121

11

21

A 300-50-52

B 200-18-16

B 100-23-211

3 100-21-19

A 406-43-AO

A 248-43-40

PL 1 Col 2

PL 1 Col 1

PL 1 Col 1

PL 1 Col 1

PL 2 Col 2

PL 1 Col 1

FY 60 x 1 1/8"

FY 65 x 2 1/16"

FY 60 x 1 5/S" n to x i n/16"

FY 80 16 3/8 x 3/8'

FY 65 x 1 5/16"

NISTNCSTAR 1-1A, WTC Investigation 503
Appendix G

SKI LLING-HELLE-CHRISTIANSEN - ROBERTSON

Coustdlin&Sliucturd QttdCtiU Engmccts • 230 Park Ave imc, New York, N. V. 10037 \ Kiu,9SS?4

/o/w D. Stilling Hclee f.lkUe John. \'; G?iftifni!>scn

June 11, 1968

Cottfudoitfi

Port of New York Authority

Office of the Construction Manager

30 Chuich Street Room 1119 New York, New York 100C7

Att: Mr. R. M. Monti

Reference: The 5>'crlc Trade Center

Contract WTC-213.C0, Pittsburgh-Dcs Moines

Paneis 154k, li/tt, Klflte T07

Gentlemen:

Mr. FiBh of PDM has contacted SHCR by telephone May 28, 1968 rcqucetin;

permission to use Plates TD7 or 3/4 inch thickness in lieu e£ 5/8 .ind 1/2 incli plates, presently shovn in the DrawingG. This request is ap- proved by SKCR. Plates TD7 occur at the top of 6pandrels at refercne

level D (7th Floor level).

v»rv truly yours,

^SKILLIKC B ELLE , /CHRISTIANSEN, ROBERTSON

James White

cc. Lester Teld :-' PNYA

H. M. Fish - PDM . William Thoma6 - PTL

W««Kt A. •«IVrC(|, \r. » , a . room . fK*MK 'ncci.ti»iior» KOMUl r. LIVIIK

f

lltKT * .. » 6 CC* • . CHA1LIC I*HSH1>

*ai.i*« c. v»a»r •

' 1 7 v y h i t c V > * "

LONtNTO L. w.otNO '.

* i a r t b r o'r r i c i

504 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

\VoiicI i».nii' Department '

I*

.'."• = Cur f. "oooii, oirtnr> ,r; *. (

R M. Monti. (/^u» Ji,-.j,.r T»

i

t r>N>»r O'Jl 0*'rf si iKr C!««-ix!.<<" ».r.*»j»f »Cl>ui(t<H. *«« Yak.SY. RUTS'

Plttsburgh-Des Moines Steel Company

Neville Island

Pittsburgh, Pennsylvania 15225

Attention: fir. H.M. Fish

Subject: The World Trade Center - Contract W7C 213.00 - Approval if Tulcknces Substitutions on ,L:- I Plates

Cent lexer

:

My letter of September 29, 1967 granted approval to increase thi thickness of certain E- 1 placco In accordance with the PittehurghDee Moines sketch No, QT-1 subject to the clarification of several

iteas. Your disposition of tbecc [tens ae outlined In the Pittsburgh-OCR KolncE letter of October 17 , 1907 has beer, reviewed

and fcund to be s a

t

tt f ac tcry

,

This will confirm that this change is approved subject to the

ur.dcrstairilr.g that there will be no additional cost to the Authority frctn Fi tteburgh-De« Hcinee and that the Authority will not backcharge Pitts burgh-Des Holnen for the additional design costs Incurred in reviewing this request.

December 18, 1967

Very truly yours,

n.ri. ponci

Construction Manager

The World Trade Center

CCt J. En41er (TFCC) , L. Robertson . (SCKR) , fi. Vernier

NIST NCSTAR 1-1A, WTC Investigation

505
Appendix G

TMt PORT OF NEW YORK AUTHORITY

11 I tifchl* Am •-><,<• .» IJih "Snrrl. S't* Yoik, NY. 1TOU

Guy f lor/oii. o .ri<ci .Hi?

VL«_s

Octx-bcr 26, 19i?

5 !t 1 1 1 ln<j -tip 1 1 o -Cht i e t J *n ut n-?j3bo r t »c a 210 far* Aveouo

iiev York., £cv Vork 10017

S-;btl«D»Di Mil DIM Lottcc o£ fc/W/37. EUCCt l«cmr «Ut»<i 9/i5/67, C. M- rtontl'e letter si*t«4 om/67

Att^.chad 1b ao October 17. 15o7 ie:;*r frc= th» f«&ri*» tneer In vliicb h« eerjca&t* t>a th« coc-Jitiooa tot cj?to\»l of

•ubetituttcn of rijtoriole cccicl cc<J la ey letter cmd Ccptcibor

29, 1967, Kindly cevlov tfcooo ccs»onc« o_-.d tivleo tta un<ior#i&a*4 ao to wttat Intorz^fltictj or ccticn 1* dov required froa tha fabri- c-tor In order ttst fi&ci epproval coq bo fliv^a to tM* rcqua«t

for eubatitutlca. Alio, civics cj to tUa ti-'j3 csd cCu-J of desl&a

for tUl« ckaa^o.

Very truly youri.

Cocatructloa !'^M;«r

Tlio V'ocld. Ttada C*Ot«r

SSC-.-2, »=dl*r (TSAC), r«l<5, ?e»»ier

506 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

ZL-3 Pittsburg*h -Des Moines Steel Company

f'dbrictitnry Kt'VILlt IV<1[: • riTTSDUPCM, PCNH1HV1.NI1 13JJJ ASIA COO« «(! PMO«[ 311 • 3 OOO

Con.-'ln.itlon October 17, 1967

Mr, R. M. Monti

Construction Manager

Rood 1119

The .Port of New York Authority

30 Church Street

New York, New York 10007

He : The World Trade Center

Contract WTC-213.0O

PDM Contract 17076 4 1713B

Gent lenon :

We wish to thank you for reviewing our letter of August 30, 1907 and granting us pcrciission to increase the thickness of plates El as outlined on attached sheet, No. QT-1, for

eleven specified columns. We understand that this permission

is contingent upon our compliance with certain provisions as outlined in your letter of September 29, 1967, and submit the

f ol Ic-'ing comments:

1. Material Specifications:

Proposed plates El will have the sane thickness

and yield strength as the adjacent plates F-l, now called for, and therefore will comply with the fiace material

specifications now included in section 203 of the specification.

2. Welding Procedure:

Wolds for proposed plates El will be made under

the sane conditions as welds now called for on plates

F-l and welding procedures with provision for preheat and

interpass temperatures will be submitted for both El and

F-l plates at an early date.

NISTNCSTAR 1-1A, WTC Investigation 507
Pittsburgh 'Des Moines Steel Company

Mr. R. M. Monti

PDM Contract l?OV a t> 17130 October 17, 2 967

We recognizo th.it this proposed change in El plates for

cloven colwnns is a t our request and no additional cost to the

Authority will bo nade by Pittsburgh-Des htoincs Steel Gorapany

for this change, Wc Also recognize that this proposed change

in plfttcs El will require redesign work by Ski 11 i ng-He 1 i e- Chr is t ianscn- l!obcr t son structural engineers and revision of

tfesigi. drawings effected by the change. If thero will be jcharato us or appreciable delays due to this redesign work, we irequrtst that wo be advised prior to final approval of this change.

Very trul y yours,

PITTSBURGH-DCS MOINES STCCL COMPANY

H. M., Fish, Project Manager

Lnc 1 osure

cc : Mr. H. A. Tessler

Manager, Project Planning

The ?ort of N.Y. Authority

Room 300

til Eighth Avenue

New York, »\'ew York 10011

w/onc copy of QT-1

t-tr. J. Endler, Asst. V.P. Tishman Realty i. Construction Co. 11th Floor, 30 Church Street

New York, New York 10007

w/one copy of QT-1

NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

i^lTTSBURGH-DES MOINES "STEEL L>u.

cont. no.) ,'7ijg sodJECT y/o^LJD /<:/££ G£riT£%' page no. Q MADE BY

^

DATE g-3o-<?7 CHECKED DY ~ DATn

WEt-DJNG DY ' DATE

Po. M <^~' 'T^SiCr'/" h/T£ 'Z/Z.oo

//V TA/£ fOC^GVS/S/ty cA

Py £ r~Y ~t

•

SO c A '. £5 4i

Co 3U 4'4 »

<— <s 3*2

SO 0 &> 4c<?e $5 •/2 ... . 33s . Co 3

3S 4L'

* ^or~ i P/ A^'as^s. -245/3 1 Y/et-O -r///c/zjv£5&

.

l£.SC ToTAt. ZTPSPS/TP t^AaJ' y/G/.-L;

'

Zf= TP<£ <£Ta/^ G. cAaj^/oT . SG.

,A}4i£aS\&&a &y A^A,<e^MA

NISTNCSTAR 1-1A, WTC Investigation 509
Appendix G

THE PORT Or NEW YORK AUTHORITY .il

.

i

World Tro cic Department

M.lkolm P, LC\Y. Chlrl. Pl>«fi*|> k rnn.ln.rliOT, D..„i 0 o

•occ=bcr IS, 19C7

PittEburgh-Dee Koines Steel Company

Neville. Island

Pittsburgh, Pennsylvania 15225

Attention: Mr, U.M. Fieh

Subject: The World Trade Center - Contract 213.00 • Approval of

lAiVcTib ASTn-A*'** I- Kod i £ ied

Cent lemon

:

Your November 2U, 1967 letter which transmitted a Lukxne Steel

Company letter dated November 20th with accompanying Lukcns

cpeci f ication for A,STM-AM1-Mcdif ied Steel revised r.'ovccibcr 16,

1967, haa been reviewed and approval of thiB cteel it hereby

granted provided it does not result in additional costo to the

Authority.

R.K. Honti

Cooetruction Manager

The World Trade Center

CC: Huaurs. L. Robertson (SHCR), W.R. Prcaalcr (PTL) - with attach,

510 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

Hvti o»e?5<

fun jilfufiftts |

MEA'llVt 14UHD

t>»0*l J3I-5O00

November 1967

Mr. R. H. Nbnti

Construction .Sarsagcr

Rco = 1119

The Port of New York Authority

30 Church Street

New York, New York 1Q007

Gcntleaen :

As requested in your 1 tttcr of October 27, 1967 v/c are enclosing one (1) copy of Lukens Steel Cccnpany ' s specif ication

icr ASTis- A-". 41- Kcc if i s.: 0

.

With the receipt of this specification we trust you will

give us final approval for the thirty-six C2 plates requested

in cur letter of August 31, 1967. If possible v;e will appreciate a phone call so wC can rclca.ee Liikens Steel Cerpar.y and

your forc-.ai letter tc follow.

The v.'orlo Trade Center

Contract WTC-213.00

PCX Contract 1707S h 17138

Very ;truly yours ,

ii. M- Fish, Project Onager

cc : Mr , H. A. Tec

Mr. Al Guttentag

HAMMOND. PRODUCTS

NISTNCSTAR 1-1A, WTC Investigation 511
Appendix G

fHE PORT C r (NEW YORK AUTHORITY

\V -V' ||< ; >Ki A.fniN- . Wwl *<•« Veil. NX I Cs.iatrwct ion Hana^at't Officu

30 Ch-.«rcn Str.ee - R*Oq VllV Wo.1,1 Tr.,di- Dc,...Mmo.., Hav Vorlt, .Sew York 1000? C,„ f i,„.-oh !>...«..

« M|...<i, (

tlMHff ^..H.v-.n I' i\. ->..:...« .

j

v /,>

October 27. 196?

Pt ttsburgh-Ecrs Hoi nee St*el C-J. Nrvl lie Tslantl Pittsburg, ^conf y IvcuU* 1 522 i

Actentiofti Mr. H. ri. i'lth

};« : The k'Oi'icS Tr4vJ<» Ontct - Cuntract WTC-213.00 -

Cent Learn

;

npyta-ml tot . <te use of t lie LuLi'iu Gt.<rvl Cw-.i«n;'s c pec i f ic s t Ion

! >: A^Al-oO steel voa jjtanied to ajr Icttci October S3ch, subject te

cpuf'.'rt-jivcc vtcit six l-.c-.CB. ? lease *>c advltcd .hat Item tt't. 5 • Table II - TeuBll* Hcqulrcicn; i jt <\£TM A'Vil -'jo t;Ueli be vlelecej iruS ;tnl,i'!iJ a*

table ii - teksi ij. p.E QUrnr-Hans

Place viity

Up to IV Inclusive Over I \" to 3" max.

Tensile strength, oln, ks I Ji Ylei<5 outJit, ciS-is , (is I <->0 Eion.vJi tan In 0", nin, ?>er c *-'" E lon£«i ton in 2". wttt, 9cr cgm

73

53

(b) fi»t'ec £j paragraph 5{tJ)

Tbir- c!;0u>;e lb a result of dlicc Oitcui-s loss fcot.'Cen ttic> Aiunc : I ty ' n CunauUant, 1 1 1 1 ng -He 1 1 o -Chr U 1 1 on oen -Robot t eon . am) the Uukene Stvcl C^. Kindly obtain froa Che I.ukeoa Steel Coapflr.y. o » pec ll icoi lor. loi tills RJtetlol

vhlch Incorporates oil oT .'to Mod I £ I cat I one fla-5 foruorU I', to the ur,(iensi£,neU tor the ?unc»e ol' couf t roans '.hrtc noJlflcoi lotta.

Stnceroiy,

E. fi. M~cti

Cor.ctr-_-ct i.-. KSSJS£?»

Ti e i.'acl«5 T»aJv Gcitfr

Con-/ to; Ke6er»;. J. R. Endler (TKCC)

512 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKI L LING - H E I L E - C H R I S i I AN S EN - ROBERTSON

< ShulIli Jim>d Cml l.n-inccn 2*0 Vuik Avenue, .Ww York. jY l\ .10)17 • .Y|u.

jrh:, (! SttM/ijj, • jMjjr j

|(Ji.'i. V Dunlumn, • l.ctfr'r K Kcfcvf>,,>,

Ciuio;( tj:-l1

I I ,-../<< I WV,;>iiTiCfn.| October 17 , 1*567 J«i!rr* > v/jr*"*"

Vor: of Kz-j York Authority

Office of tho Construction Knaaftcr 30 Church Street

\ic\i Vort, 1'cv VorV.

Attcriticr:: Hr. ft. f'or.ti

f ftrcrico : The 'r-'orld Tr/rdc Center

Crntroc •--C-213.00. T>C;i 't:r.l r^ntr f-.iUct i tut i 5r.n CAPT?) t.'.f.X Hod.)

Ocm 1 k— :

ru.-.Ec rcicr to our lector of "etcber II. J?C7, cirteursntnj? the above

cn;>tler:c?t! subject. It«s 3, Table II, shovn on fnp.e 2 of our lector clisll hi Mpleccd with the follc-ln-

:

S. TcbJc li - 'tensile KCTUirrzjcnt r of ASTl A4£l-C-£: naoll bo

TA MLr II - ti . s:-i l:: nrrui;o~<r:,i:

Up lo m" Inclusive Over IV to 2"

Vcr.iilc cCTPrif.th, rslr, It' 75 75

'field point, Din. Ucl 00 55 Ulceration In B", z.ir. , per ccr.r 18(a)

*.*lCr«-.«ct 1 kJU III 7 . Clill, pvl LCIli 4.H

!U> -''-Or co porr.sr.nnl'i S(rt)

'SOflt c

NISTNCSTAR 1-1 A, WTC Investigation 513
Appendix G

S KILLING - HELLE - CHRISTIANSEN - ROBERTSON

This revision 1c m cccorJ?ncc vlth f irol d:tu received fron LuVcrsn Steel

Cccivany r»y telephone cr, Monday, October 16, 1067.

PL1 !! c^o-.il'J fisV. Lu'Kcnn Co furnish c final copy of LuV.cnn' nptclfic.TCion of

Liiiu rjiLcriai con r irrsinf. the iiau iri chls icccor nruv our letter of October II, 1067.

J'.rjr.ti OcteVsr 17, 1907

sr. I ll i: : c • ILL e- c: t. i si Ltt a - p.n.ir tit s ok

!. . Tel-.;, "HYA

I!. ?icli.

R.E

514 NISTNCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKiLLING - HELLE-CHRISTIANSEN - ROBERTSON

Consutcing S('uciuToi and Civil Engineers • 2S0'Path A\*r.ue, New York, N. V. 10017 • Ma. WS"'/

/oAn D. Shilling • Hdfitf /. Hditf • /c/m. V. Cfcwiidnsrn • L«li* E. Roocrfjcu

May j, 1958

HeroidL Wetthtngton

hi*?* F. U-~': >

Port of New York Authority

Office of the Construction

Manager - Room 1119

30 Church Street New York, New York 10007

Attention: Mr. R. M. Honti

Refereace: The World Trsdc Center Contract WTC-213.00, Pittsburgh-Des Koines

Radiographic T Tispection

Cent leaen

:

Mr. Fish of PDM has asked permission to revise the radiographic Inspection

provisicas presencly included in che PDM quality control prcgrao as they

relate to the f ull-penetraticn butt weld joining spandrel plate D4 (shewn ca the shop drawings as plate "c") and plate E3 (shown or. the shop drawings as plate "k") . SHCR has reviewed thie request, and suggest that the following prcgraa be followed.

1. The first 16 column trees in Tower A shall have one' radiograph

taken at each end of the 6vibject full-penetration veld.

2. Should no defective weld be found, one radiograph at one end cf the subject weld will be required for each remaining column tree.

3. For each defective length of weld found, one additional colviua tree shall be subjected to one radiograph at each end of the subject weld.

r. 1 . A. rOITII

ovrar r. »vrt»

y. *, r m - .SIK1

K(ltT *, 9 <S 0 I » o wikLim fc . m k* c r. ^ . wMirr. j".

• U I L C I C T D - I III

NISTNCSTAR 1-1A, WTC Investigation 515
Appendix G

SKILLIN6 - HELLE-CH RISTIANSEN - ROBERTSON

4>. Where a radiograph shovs a length of defective weld, the adjacent

length of weld (approximately 16") shall be radiographed. If no additional defects arc indicated, the subject weld will require

no additional length to be radiographed,

5. All defects found by radiography shall be repaired and shall be

subjected to re-inspection by radiography.

This program will concentrate radiographic testing performed by PDM on

the ends of the full-penetration weld along Reference Line No. 2 (approximately SB-3/t" long), thereby concentrating on the cost critical lengths

of the subject weld. The additional benefit of the above program is that

the amount of radiography reqired for a giveo panel is greatly reduced in

comparison to the 100 percent retirement stated in the PDM quality control

program. The overall percentage of weld inspected in the program outlined

above is comparable to that originally required in the PCK quality control

program. Ho suggest that 16 radiographic tests be allocated by ?DK to random assignment by the PH. Inspector at locations selected by Che PTL inspector after the start of fabrication of column-tree panels for Tower B.

In order to eiake absolutely sure that there is no confusion ia identifying

the weld referred to in this letter, the weld under discuesioo ia the fullpenctratior. weld shown in detail 19, sheet 2-AB2-11, Drawing Book 2.

Very truly yours,

SKILLIUC, E£LLE , CHRISTIANSEN , ROBERTSON

FtfYA 2 Hay 3, 1968

JVfjtB

cc: Mr. L. S. Feld, PNYA

Mr. H. M. Fish, PDM

516 NIST NCSTAR 1-1A, WTC Investigation
Supporting Documents for Chapter 8

SKILLINS-HELLE-CHRISTIANSEN - ROBE RTS O N

Consulting Structurcl and Ci\il Engineers • 210 Park Avenue, New Yvtk, N. V. JOCiT • Mb, *ta$?>J

Jo/m fl. Stilling liclge ] . Hcllc • fohn.V. Chrktumctt • I-«ifiV £. /lobrrf.voii April 18. 1968 Cnvultch

L Wnrl/unctrtil

loicph F. /jrtn«;i Port of Kew Tork Authority

Office of the Coos true r.ltm Manager - Roots 1119 30 Ciinrch Street Hew York, New York 10007

Attention: Kr. R.M. Monti, Construction Manager

Reference: 3H» S'tld Trade Center

Contract \rrr. '17.00. °t~r~~

Magnetic particle testing

Geatleaea:

We bavo rcviovad tlv. Staaray lottcr dated March 26, 1963, recuestlns

peralsslcn to inspect a olr.imrs of tea percent of the linear footage

of velds oa dm flange of one ooreber out of each two fabricated neuters

at such tioos that the rejection rote of v©ldn allows the ttlnlcua inspection rite, Wc approve this change to the Stanray Pacific

quality control proprom.

Very truly youre, billing, HFiir., a:xisrL\hSr_N, rceertsox

JXJ:kc

cc: Ht. Lbbcct Fcjc, r\N"!A Kr. P-obcrt Morris. STAJ1RS.Y

bcc:Mr. Richard Chaune-r, SHCR, SE. 1

• - * / C » - r * MOIVU

»o«i*i C- bC * "I *

v. *, rn i» * s * •

* IINT . »eCTM

(to* Nil* »*..*>. • * <MiUi,iA« a. w » •> c

I . J. XMITI • *

NISTNCSTAR 1-1A, WTC Investigation 517
Appendix G

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518 NIST NCSTAR 1-1A, WTC Investigation