chnical Committee 1 : smic Risk Maps

the deliberations of a group of professionals jointly

Safety Council and the National Bureau

odifying the Tentative Provisions for trial designs.

October 1980

NATIONAL. BL'HKAl or standards

10BRARY

NBSIR 80-2111-1

REVIEW AND REFINEMENT OF ATC 3-06 TENTATIVE SEISMIC PROVISIONS

MAY 1 8 1981

r\o-t o-cc . - /

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REPORT OF TECHNICAL COMMITTEE 1: SEISMIC RISK MAPS

S. T. Algermissen, Chairman, United States Geological Survey

Bruce R. Ellingwood, Secretary, National Bureau of Standards

Riley Chung, Assistant Secretary, National Bureau of Standards

William F. Marcuson, III, American Society of Civil Engineers

Howard A. Spellman, Association of Engineering Geologists

Jerry Harbour, Interagency Committee on Seismic Safety in Construction

Robert^ Englekirk, Structural Engineers Association of California

Neville C. Donovan, Applied Technology Council

William LeMessurier, Building Seismic Safety Council

Prepared for use by the:

BUILDING SEISMIC SAFETY COUNCIL

Sponsored by:

FEDERAL EMERGENCY MANAGEMENT AGENCY

Center for Building Technology

National Bureau of Standards

Washington, D.C. 20234

October 1980

U.S. DEPARTMENT OF COMMERCE, Phillip M. Klutznick, Secretary

Luther H. Hodges, Jr., Deputy Secretary

Jordan J. Baruch, Assistant Secretary for Productivity, Technology,

and Innovation

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
-

i
ABSTRACT

The TENTATIVE PROVISIONS FOR THE DEVELOPMENT OF SEISMIC REGULATIONS FOR

BUILDINGS were developed by the Applied Technology Council to present,

in one comprehensive document, current state-of-knowledge pertaining to

seismic engineering of buildings. The TENTATIVE PROVISIONS are in the

process of being assessed by the building community. This report is one

of a series of reports that documents the deliberations of a group of

professionals jointly selected by the Building Seismic Safety Council

and the National Bureau of Standards and charged with reviewing the

TENTATIVE PROVISIONS prior to the conduct of trial designs. The report

contains the recommendations and records of the committee charged with

review of the seismic risk maps. The committee made 4 recommendations

for revisions to the TENTATIVE PROVISIONS. These recommendations were

made to the parent group, the Joint Committee on Review and Refinement,

and their action on these recommendations is documented in a companion

report.

Keywords: Buildings; buildings (codes); buildings (design); earthquakes;

seismic risk maps; standards; structural engineering
-

•• • .

.. \

•' Is i . , f • r - ' ' '
TABLE OF CONTENTS

Page

1.0 Introduction 1

1.1 General 1 1.2 Committee Summary 1

2.0 Committee Actions 6

2.1 Recommendations for Change 6

2.2 Recommendations for Trial Design 7 2.3 Recommendations for Commentary 7 2.4 Other Recommendations... 7

3.0 Committee Records 8

3.1 Meeting Minutes 9

3.2 Committee 1 Roster 12

3.3 Selected Committee Correspondence 14

3.4 Comments by ATC Representative on Ballot Items 24

iv
.

-

> -

-

- * •

• '

...

' '

3 * * • •

-
1 .

0

INTRODUCTION

1.1 General

The Tentative Provisions for the Development of Seismic Regulations were developed by the Applied Technology Council in an effort that included

a wide range of experts in the actual drafting of the provisions. Two

external review drafts were circulated to a large portion of the interested

and informed community of eventual users. However, because the Tentative

Provisions were innovative, doubts about them existed. Consequently, an attempt was made to investigate these doubts and to improve the Tentative

Provisions where possible before an expensive assessment of the Tentative

Provisions was undertaken by conducting trial designs.

This review and refinement project was planned arid conducted by the National

Bureau of Standards with the advice arid approval of the Building Seismic

Safety Council, a private sector organization formed in 1979 for the

purpose of enhancing public safety by providing a national forum to foster

improved seismic safety provisions for use by the building community.

The assessment of the Tentative Provisions was performed using the committee

structure shown in figure 1. Nine Technical Committees were formed with

interests that collectively cover the Tentative Provisions . The Joint

Committee on Review and Refinement consists of all voting members of the

Technical Committees. The chairmen of the Technical Committees form a Coordinating Committee.

Membership of each Technical Committee is made up of representatives of

organizations that have particular interest in the Tentative Provisions ; the participants are listed in the committee membership section of this

report. >

In addition to the voting members, each Technical Committee includes a non-voting member from each of the following organizations: The Applied

Technology Council (ATC), the Building Seismic Safety Council (BSSC)

and the National Bureau of Standards (NBS). The ATC representative served

as a technical resource to the committee since he was closely involved with

the development of the provisions of interest to the committee. The NBS

representative was the technical secretary throughout the effort. The

BSSC representative provided a link with the Building Seismic Safety

Council, which will be involved in trial designs and evaluations.

1.2 Committee Summary

Technical Committee No. 1 on Seismic Risk Maps had as its objective the

determination of whether the provisions in Section 1.4.1 of the ATC

Tentative Provisions , entitled Seismicity Index and Design Ground Motions,

are adequate for the trial designs and impact assessment that must be made

before they can be considered for regulatory documents.

Committee 1 held its first meeting on December 11, 1979, at the National

Bureau of Standards. Various issues raised in connection with Section 1.4.1

and its commentary were discussed at some length at this meeting and the

1
JOINT COMMITTEE ON

REVIEW AND REFINEMENT

COORDINATING

COMMITTEE

TECHNICAL COMMITTEES

Comitt ee 1: Seismic Risk Maps

Committee 2: Structural Design

Committee 3: Foundat ions

Committee 4: Concrete

Committee 5: Masonry

Committee 6: Steel

Committee 7: Wood

Committee 8: Architectural,

Mechanical, and Electrical

Committee 9: Regulatory Use

Figure 1: Committee Structure
minutes are included in Section 3.1 of this report. Following this meeting,

each committee member was invited to submit proposals for possible revisions

of the provisions that should be made before trial designs are conducted.

At least one committee member solicited comments from his professional

colleagues as well (see Section 3.3). These proposals for change, summarized

in Table 1, were circulated for information among the committee membership

by the Secretariat in January, 1980, and at the same time were sent to

the ATC representative for his response.

Because of the small number of proposed changes originating within Committee 1 and the fact that the substantive issues had already been discussed at the

December meeting, it was decided that a second committee meeting, originally

scheduled for February 21, 1980, need not be held. Accordingly, a ballot

was prepared and was distributed to the five voting members of the committee

on April 10, 1980. The responses of the ATC representative to the proposals

for change were received by the Secretariat about a week later and were also

distributed to the voting committee (see Section 3.4). The final outstanding

ballot was returned to the Secretariat June 4, 1980. The results of the

ballot are shown in Table 2. Those items that were affirmed by a majority

of voting members of Committee 1 are presented as recommendations to the

Joint Committee in Section 2 of this report.

3
TABLE 1: SUMMARY OF TECHNICAL COMMITTEE 1 BALLOT ITEMS

Proposed Changes to ATC 3-06: April 1, 1980 Ballot

Item

1 .

2 .

3.

4.

5.

6

.

7.

8 .

Proposed Change

Table 1-A: Change the Seismic Performance

Category for Seismic Hazard Exposure III

buildings located in areas with Seismicity

Index of 1 from A to B.

Table 1-B: Change Seismicity Index for Map

Area 5 from 4 to 3 .

Table 1-B: Change Seismicity Index for Map

Area 4 from 3 to 2 .

Table 1-B: Change Seismicity Index for Map

Area 3 from 2 to 1.

Table 1-B: Change Seismicity Index for Map

Area 2 from 2 to 1 .

Table 1-B: Change Seismicity Index for Map

Area 1 from 1 to 0.

The accelerations should be represented by a contour map (in percent gravity) rather than

by county boundaries.

Change Section 1.4.4 to read: "No new building

or existing building which is, because of change

in use, assigned to Category D shall be sited on an active fault."

Add the following definition:

An active fault is one on which there is evidence

of tectonic movement in the past 10,000 years,

i.e., Holocene displacement.

4
TABLE 2 - TECHNICAL COMMITTEE 1 BALLOT RESULTS

Ballot Issued: April 10, 1980

Due: May 1, 1980

Item 1 Short name Yes No Yes, with

Reservations

1 Table 1-A 2 3

2 Table 1-B (5) 2 3

3 Table 1-B (4) 2 3

4 Table 1-B (3) 2 3

5 Table 1-B (2) 3 2

6 Table 1-B (1) 3 2

7 Acceleration map 3 2

8 Sect. 1.4.4 2 2 1

Name:

Signature:

Date:

5
2.0 COMMITTEE ACTIONS

2.1 Recommendations for Change

Technical Committee 1 on Seismic Risk Maps recommends to the Joint Committee

four changes to Section 1.4 of the ATC Tentative Provisions . The first two

originated from within Committee 1.

(1) The design ground motions defined in terms of Effective Peak Acceleration or Effective Peak Velocity-Related Acceleration should be represented

by contour maps (in percent gravity) rather than by counties.

Reason : Contours permit a degree of judgment by the user without penalizing

the building industry in portions of the country where earthquake and fault

records are not as abundant as in the western states and where the zone boundaries are not well defined. The increase in accelerations between

zones is enough to penalize buildings in these border areas, some of which

are areas of heavy construction. Contour lines are easier to relocate as additional data become available. Seismic risk in large counties close

to zones of active faulting also could be treated more consistently.

Opposing points of view were that code administrators prefer a county-type

map, and the specification of zones avoids the need to extrapolate ground

acceleration at certain boundaries of the contiguous 48 states.

(2) Change Section 1.4.4 to read: "No new building or existing building

which is, because of change in use, assigned to Category D shall be sited

on an active fault." Add the following definition : "An active fault is one on which there is evidence of tectonic movement in the past 10,000

years, i.e., Holocene displacement."

Reason: Editorial improvement, includes definition of an active fault.

However, one affirmative vote was cast with the reservation that the definition does not cover fault strands, conjugate faults, or associated faults

for which no direct evidence of movement exists but which are so related

to an active fault that activity on one may be as likely as on the other.

In addition to these proposals, several proposals for changing the values

of Seismicity Index In Table 1-B of the ATC Tentative Provisions were sent

to Committee 1 for ballot as well as to other Committees. The reasons advanced for the proposed changes are described in detail in Section 3.3,

Correspondence. Briefly, it was felt that buildings located in map areas 1 and 2, and probably map area 3, would remain elastic under design ground

accelerations and thus additional requirements for detailing to insure

ductility over existing practice are not necessary. The view was also

expressed that in map areas 4 and 5, the sudden additional requirements

for detailing for ductility are not supported by adequate background studies.

The ballot of Committee 1 on the proposed changes to the seismicity index

classification resulted in the following proposed changes:

6
(3) In Table 1-B, change seismicity index for Map area 2 from 2 to I .

(4) In Table 1-B, change seismicity index for Map area 1 from 1 to 0 .

All other proposed changes to Table 1-B failed by a simple majority.

2.2 Recommendations for Trial Design

None

2.3 Recommendations for Commentary

None

2.4 Other Recommendations

None

7
3.0 Committee Records

This section contains records of Committee 1 activities that relate

to the review of Section 1.4.1 of the ATC Tentative Provisions . Section 3.1 contains committee meeting minutes; Section 3.2 lists

membership; Section 3.3 contains copies of selected committee

correspondence; Section 3.4 gives the ATC comments on the ballot

items listed in Table 1.

8
3.1 Ileeting Minutes

Minutes of First Meeting

Technical Committee 1 - Seismic Risk Maps

Review and Refinement of Tentative Seismic

Provisions (ATC-3-06)

at

National Bureau of Standards

December 11, 1979

The meeting was called to order at 12 noon by the NBS secretary of the

committee, Bruce Ellingwood. Those attending were:

Name

Jerry Harbour

Howard Spellman

William LeMessurier

William Marcuson

Neville Donovan

Robert Englekirk

S. T. Algermissen

Riley Chung

Bruce Ellingwood

Representative of

Interagency Committee on Seismic Safety in

Construction

Association of Engineering Geologists

Building Seismic Safety Council

American Society of Civil Engineers

Applied Technology Council

Structural Engineers Association of California

United States Geological Survey

National Bureau of Standards

National Bureau of Standards

As a first order of business Ted Algermissen was elected chairman of the

Technical Committee.

There was a period of discussion on whether Committee 1 should be represented

on Committee 2: Structural Design. Most of Committee 1 felt that because

of numerous problems in adapting ground motion information to structural

design, that Committee 1 should be represented as a voting member on Committee 2. It was pointed out that the map accelerations are related

to the control of force, deformation and damage. Therefore, Bob Englekirk

was elected to be the voting representative of Committee 1 on Committee 2.

9
The remainder of the meeting was spent discussing a number of points raised

by reviewers of earlier versions of ATC-3-06 . These points may be

summarized as follows:

1. Justification of level of probability of occurrence of ground motion.

2. The need for two maps and identification of parameters to be mapped.

3. The use of zones rather than contours and the selection of county lines

for zones boundaries.

4. The number of zones versus the number of seismicity indices.

5. Lower ground motion in high-risk areas than the original AlgermissenPerkins open file report map.

Each of these points was discussed in some detail by the committee. With

regard to levels of probability of exceeding the recommended ground motion,

it was pointed out that the question of what probability to select cannot

be answered outside the context of the problem. The 50-year time scale

was selected as one being of interest to building codes. The selection of

a ten percent exceedance probabil ity in this 50-year period was a consensus

of a number of experts and was consistant with values that were being

assumed or were being recommended in several independent studies. The

committee felt that the explanation given on page 302 of ATC-3-06 was a satisfactory explanation of the selection of a risk level.

With regard to the specification of two maps, the committee was in

unanimous agreement that earthquake ground motion is much too complicated

a problem to be specified by simply one parameter. While ground acceleration may not always be the best parameter to map, there was a consensus that it

was the best parameter if one had to be selected. The committee recognized

that while A penalizes low period buildings in some instances, it was necessary for this parmeter to be included for longer period structures.

The maps were drawn on the basis of historical seismicity of the sites.

There was little data available on rate of occurrence at the time the

maps were put together. It was not considered practical to have additional

maps corresponding, for example, to different map parameters or to

different durations of shaking.

With regard to the selection of zones rather than contours and the selection

of county lines as the boundaries for the zones, it was pointed out that

code administrators favored this approach. Moreover, the specification

of zones avoids the need to extrapolate ground acceleration at certain

areas of the boundary of the contiguous 48 states. However, it was also pointed out that the county zoning system does violence to the

concept of ground motion and the contour lines are easier to relocate

as additional data become available. Moreover, the increase in accelerations

between zones 2 to 3 is enough to penalize buildings in these border

areas, a problem because the placement of zone boundaries are not well

defined. Some of these boundaries occur in areas of very heavy construction

in the United States. No general agreement was obtained on whether the

10
trial designs should be based on the zone or contour concept of seismic

risk mapping and this problem remains to be resolved in a later meeting.

The committee discussed the use of seven zones and four seismicity

indices and sees no problem with this particular differentiation in

ATC-3-06 .

With regard to the lower ground motion in certain high risk areas, it

was pointed out that the areas in which the effective peak acceleration

exceeds 0.4g are very small and that specification of higher accelerations

would require microzonation. The committee does recognize that this

clipping of peaks higher than 0.4g as well as the smoothing of contours

does alter the basic probability that the basic ground motion will be

exceeded.

It was decided that the next meeting of Technical Committee 1 would be

held Thursday, February 21, 1980, at the U.S. Geolglcal Survey in

Golden, Colorado. Each committee member is to review Section 1.4.1 and

the related commentary of ATC-3-06 and make proposals for any revisions

that should be made before trial designs and impact assessment is begun.

These proposed revisions should be submitted in writing with supporting

evidence and reasoning to the conmittee secretary and to the representative of ATC by January 11, 1980. The ATC representative will

review the proposed revisions and transmit them to the secretary by

Janaury 30, 1980. The secretary will then distribute all proposed

revisions and ATC responses to all members of Committee 1 prior to the

February 21 meeting at which time issues raised will be deliberated by

the committee members.

There being no other business, the committee meeting was adjourned at

4:00 p.m.

Respectfully submitted.

Bruce Ellingwood Secretary

Enclosure: Roster of Membership for Committee 1 including telephone numbers

11
3.2 Committee 1 Roster

COMMITTEE 1: Seismic Risk Maps

American Society of Civil Engineers

Mr. William F. Marcuson, III

Waterways Experiment Station

P.0. Box 631

Vicksburg, Mississippi 38180

Association of Engineering Geologists

Howard A. Spellman

Converse Ward David Dixon Association

126 W. Delmar Boulevard

Pasadena, CA 91105

Interagency Committee on Seismic Safety in Construction

Mr. Jerry Harbour

Chief, Site Safety Research Branch

U.S. Nuclear Regulatory Commission

Mail Station 113055

Washington, D.C. 20555

Structural Engineers Association of California

Dr. Robert Englekirk (representative to Committee 2 3242 West 8th Street Structural Design)

Los Angeles, CA 90005

United States Geological Survey

S. T. Algermis'sen (Chairman)

U.S. Geological Survey

Denver Federal Center

Box 25046 MS966

Denver, CO 80225

Applied Technology Council

Mr. Neville C. Donovan

Partner, Dames & Moore

500 Sansome Street

San Francisco, CA 94111

12
Committee 1 (continued)

Building Seismic Safety Council

Mr. William Le Messurier

Chairman, Sippican Consultants

International, Inc.

1033 Massachusetts Ave.

Cambridge, Massachusetts 02138

National Bureau of Standards

Dr. Bruce Ellingwood

Dr. Riley Chung

Secretariat

Committee 1, Seismic Risk Maps

National Bureau of Standards

Rm. B-168, Bldg. 226

Washington, D.C. 20234

13
3.3 Selected Committee Correspondence

This section contains a record of correspondence related to proposed changes

in Section 1.4.1 of the ATC Tentative Provisions . Other committee correspon'

dence has been retained by the Secretariat but is not included.

Exhibit A) Letter from Marcuson soliciting comments on the Seismic Risk

Maps from the ASCE Committee on Soil Dynamics.

Exhibit B) Letter from Spellman on contours vs. county barriers in risk

mapping.

Exhibit C) Letter from Spellman suggesting a revision to site limitation

provision 1.4.4.

Exhibit D) A suggestion from Mark Fintel for revising Table 1-B.

Exhibit E) A suggestion routed through Committee 5 on Masonry for

revising Table 1-B; however, it should be noted that their

suggestion to revise seismic performance categories falls

outside the purview of Committee 1 and, in addition, contains

an unintentional error (see not on exhibit E).

Exhibit F) A suggestion routed through Committee 4 on Concrete for

revising Table 1-B.

14
Exhibit A

AMERICAN SOCIETY OF CIVIL ENGINEERS

GEOTECHNICAL ENGINEERING DIVISION

12 December 1979

To: Committee on Soil Dynamics

SEE DISTRIBUTION

Subject: Review of Applied Technology Counsel's (ATC) "Tentative Provisions

for the Development of Seismic Regulations for Buildings"

Gentlemen

:

I have been asked to represent the American Society of Civil Engineers (ASCE)

and serve on a committee to review and refine the subject seismic provisions.

Specifically, I serve on a subcommittee charged with review of the seismic risk

maps. The question that we are addressing is: "Are the seismic risk maps acceptable?"

The purpose of this letter is to bring your attention to the fact that this

review is going on. Now is your time to criticize the subject tentative seismic

provisions. If you do not have a copy of this document, one can be obtained from

the National Science Foundation by ordering their publication #78-8 , or from the

National Bureau of Standards by ordering their Special Publication #5-10.

The specific area that our subcommittee is investigating can be found on pages 28

and 29 in section l.Ll and on pages 296 to 333 of the commentary. If you find

anything unacceptable, please make specific recommended changes, for example: on page 28, the second paragraph of section 1.4l, the fourth line down, the word

"potential" should be deleted.

Please send your proposed changes to:

Mr. Bruce Ellingwood

Technical Committee on Seismic Risk Maps

Tentative Seismic Provision Project

Bl68, Building 226

National Bureau of Standards

Washington, D.C. 2023^

by January 11, 1980. If this deadline is unacceptable, proposed changes will be

accepted on up into February.

15
To: Committee on Soil Dynamics 12 December 1979

Subject: Review of Applied Technology Counsel's (ATC) "Tentative Provisions

for the Development of Seismic Regulations for Buildings"

Please send copies of your proposed changes to:

Mr. Neville Donovan

Dames & Moore

500 Sansome Street

San Francisco, CA 94111

Mr. S. T. Algermissen

U. S. Geological Survey

Box 25046, MS 966

Denver Federal Center

Denver, Colorado 80225

Mr. T. Leslie Youd

U. S. Geological Survey

345 Middlefield Road, MS 98

Menlo Park, CA 94025

and me.

Your review and critique of the subject document is not limited to the seismic

risk map portion. You are welcome to comment and make specific recommended

changes on any portion of the document; however, I have been specifically charged

with review of the seismic risk maps

.

Now is the time to speak out if you have any "heartburn" whatsoever. As the

saying goes, "Speak now, or forever hold your peace." Your efforts in this regard

are very much appreciated.

Please pass this information on to any friends, colleagues or associates who you

believe should be aware of this current review.

Let me take this opportunity to wish each of you a Very Joyous Holiday Season

and a Healthy, Happy, Prosperous New Year.

Sincerely,

'gut

. W. F. MARCUSON, III

Research Civil Engineer

Earthquake Engineering and

Geophysical Division

Geotechnical Laboratory

16
To: Committee on Soil Itynamics 12 December 1979

Subject: Review of Applied Technology Counsel's (ATC) -'Tentative Provisions

for the Development of Seismic Regulations for Buildings"

DISTRIBUTION

D. G. Anderson

Ralph Brown

V. P. Drnevich

Maurice Power

John Lysmer

Jim Bell

Yung Chae * . Marshall L. Silver

Kenneth H. Stokoe, II

John T. Christian

T. L. Youd

Ted Vincent

Lyman Heller

Harch Singh

Bob Pyke

CF

Neville Donovan

Ted Algermissen

Bruce Ellingwood v

17
Exhibit B

January 8, 1980

Howard A. Spellman, Past President

c/o Converse Ward Davis Dixon, Inc

P.O. Box 2268D, Pasadena, CA 91105

(213) 795-0461

Dr. Bruce Ellingwood, Secretariat

Committee 1, Seismic Risk Maps

National Bureau of Standards

Room B168, Building 226

Washington, D.C. 20234

Subject: Contours vs. County Boundaries

Dear Dr. Ell ingwood:

The subject map is the very foundation for design ground motion for the "Tentative Provisions for the Development of Seismic Regulations for Buildings" (ATC-3-06).

As such, it is the opinion of the Association of Engineering Geologists (AEG) that

representation of Effective Peak Acceleration (Aa), as modified from USGS (Open-File

Report 76-416 by Algermissen and Perkins (1976), is more practical if expressed by

contours (in percent gravity), than the proposed county boundaries. Principal rea- son(s) follow.

Countours (as in Fig. Cl-3, Page 316) permit a degree of judgment by the user without penalizing the building industry in portions of the country.

Exarnpl

e

, one of many;

- the heavy construction areas in the eastern states (Pennsylvania, Virginia,

New Jersey, New York; the New England states, etc.) where earthquake and

fault records are not as abundant as in the western states.

Conversely, western states would have the flexibility to reduce or exceed

0.40g by documenting local microzonation.

- assigning a higher seismic risk to a zone of major active faults along the

western boundary of Nevada; i.e., 0.30g to 0.40g rather than the 0.15g to

0.20g presently prescribed and lowering the seismic risk in central Nevada

(Ryall and Van Wormer, 1979).

AEG is understood to believe county boundaries are preferred by code administrators, but we also believe county boundaries could be a disservice to the building

industry and the design engineer.

Sincerely yours.

Map for Coefficient Aa" Figure 1-1

Exarnpl

e

:

Committee Member

HAS: hi

c

cc: N. C. Donovan

J. B. Ivey

18
Exhibit C

Howard A. Spellman, Past President

c/o Converse Ward Davis Dixon, Inc. P.O. Box 2266D, Pasadena, CA 91105

(213) 795-0461

January 9, 1980

Mr. Ted Algermissen, Chairman

Committee 1, Seismic Risk Maps

U.S. Geological Survey

Denver Federal Center

Box 25046 MS 966

Subject: Revision of Section 1.4.4 and Definition of

Active Fault

Dear Ted:

As promised December 11, 1979 at our Washington, D.C. meeting, The

Association of Engineering Geologists suggests the following revision of Section 1.4.4 and a definition of active fault that could

be applied nationwide. Considering the 28 definitions of " Active

Fault" in the Corps of Engineers Miscellaneous Paper S-77-8

(Slemmons, 1977) there is no definition that will appeal to all

entities. However, the following should stir up some beneficial

discussion

1.4.4 ‘ SITE LIMITATION FOR SEISMIC DESIGN PERFORMANCE

CATEGORY D

No new building or existing building which is, because

of change in use, assigned to Category D shall be sited

where-there is the potential for an aetive fault to

eause rupture of the ground surface at the building on

an active fualt.

Am looking forward to our February 21, 1980 meeting in Golden, Colorado.

Best regards,

Definition:

An active fault is one on which there is evidence of

tectonic movement in the past 10,000 years ie, Holocene

displacement

Howard A. Spellman, Jr

Member Committee 1

HAS/hg XC: Dr. Bruce Ellingwood,

Secretariat

Mr. John B. Ivey,

19
Exhibit D

Submitted by

Portland Cement Association

Mark Fintel

January 1980

TABLE 1-8 - Page 35

REVISE THE "SEISMICITY INDEX" COLUMN OF TABLE 1-B TO READ AS SHOWN BELOW:

TABLE 1-B

Coefficients A

fl and A

y

and Seismicity Index

Coeff. A Map Area Coeff. A„ Seismicity

Figure l a Number Fiqure 2 Index

0.40 7 0.40 4

0.30 6 0.30 4

0.20 5 0.20 t 3

0.15 4 0.15 J 2

0.10 3 0.10 2 1

0.05 2 0.05 l 1 0.05 1 0.05 1

REASON: The seismicity indices were Introduces as a device to relate the

seven map areas (acceleration intensities) with the various levels of

detailing requirements, as classified in the four seismic performance

categories (A, B, C, and D). The indices and the performance categories

have been apparently arbitrarily interrelated with the seismic hazard

exposure groups (Table 1-A).

While there is little question about detailing requirements for the

highest seismicity (4), and for the lowest seismicity (1), detailing

requirements for seismicity index levels of 2 and 3 remain a gray area

without adequate background information.

20
It is not acceptable to require arbitrarily the same level of ductility

detailing for acceleration levels of .40 (map area 7) as for acceleration

level 0.15 (map area 4).

Buildings located in the map areas 1 and 2, subjected to acceleration

levels of 0.05, will undoubtedly always remain in the elastic range,

requiring no additional ductility details. The acceleration level of 0.10

(map area 3) will, in all probability, create an elastic response in

buildings designed in conformity with modern reinforced concrete and steel

codes.

Regarding the acceleration levels of 0.15 and 0.20, (map areas 4 and 5),

the major question is which structural members will be yielding and how much

ductility will be required in them. It should also be considered that

current codes (i.e., ACI 318) basically result in ductile members, as provisions over the last 20 years have been devised to eliminate brittleness. To

suddenly require additional detailing (also adding 30% of forces in perpendicular direction) in cities like New York and Chicago, based largely on

judgment, not necessarily supported by adequate background studies, seems

questionable. Seismic code writers bear the responsibility to substantiate

the need for any restrictive changes made to codes which have been developed

in a consensus process over the last several decades. It is not for

Industries to prove that such changes are unnecessary and will increase the

cost of buildings without adding to their safety. Added ductility requirements should be Imposed only if seismicity vs ductility correlation studies

for map areas with acceleration levels of 0.10, 0.85 and 0.20 indicate

levels of ductility demands requiring such detailing.

21
Exhibit E

Proposed change : table 1-B

COEFFICIENTS A and A and SEISMICITY INDEX

a v

Coefficient A

Figure 1 a

Map Area

Number

Coefficient A

Figure 2 a Seismicity

Index

0.40

0.30

0.20

0.15

0.10

0.05

0.00

7

6

5

4

3

2

1

0.40

0.30

0.20

0.15

0.10

0.05

0.00

4

4

3

2

1

10

The ATC says in their commentary that they assigned the

arbitrary peak acceleration of 0.05 g to map area 1.

The actual seismicity of map area 1 is actually zero. In addition, the peak acceleration of map area 2 is

actually 0.00 to 0.05 as maximum.

It is the intention that any reasonably designed and built

structure will survive a peak acceleration of 0.05 intact

and all materials remain within the elastic range. Therefore, the Coefficients of Map Area 1 is recfiuced to 0.00

and the Seismicity Index for that area is reduced to 0.

The other Seismicity Indices are adjusted accordingly.

Proposed change : TABLE 1-A

SEISMIC PERFORMANCE CATEGORY

Seismicity

Index

4

3

2

1

Seismic Hazard Exposure Group

III II I

D C C

C B

Suggested change B Error _ should©&

from A to B was ^ have been B A

voted down by

Committee 2.

The reasoning for these proposed changes is as follows:

.1 It is felt that Seismic Hazard Exposure Group III

Buildings should be investigated and analyzed, even

for Seismicity Index 1.

.2 It is also felt that based on performance history,

S.U.E.G. I Buildings in S.I. 2 need not be required

to be reinforced masonry.

22
Exhibit F

C

JOif *•

r*. rr—

r

CONCRETE REINFORCING STEEL INSTITUTE

fw <u V' I4«C BAV SHORE HIGHWAY SUITE IN' bUR; INGA'.U CA S4>»iC> THEPhON; 415 6WI4C' 7

H c> WANNING K«#yior.o' C.iiiftor CRSl Westc' n Region

January 31,1980

Members of Techncial Committee 4

Concrete

Review of ATC 3-06

Victor Bertero

Edward Cohen

Mark Fintel

Neil Hawkins

Eugene Holland

Gentlemen:

The following proposed revisions to ATC 3-06 are submitted for

your consideration. These are written in code language, with

appropriate reasons for each per instructions by the Committee

Chairman.

James Lefter L ro Richard Marshall sr James Prendergast %

David Sheppard

Table 1-B Seismicity Index

Revise the "Seismicity Index" of table 1-B to read as follows:

Map Area Seismicity

Number Index

7

6

5

4

3

2

1

4

4

4 3

3 2

2

7 1

1

Reason: The seismicity index relates to various levels of detailing requirements through the seismic performance category. Under

ATC 3-06, in some areas such as Phoenix, AZ ., detailing requirements

would be increased to the same level as that for say San Francisco.

This obviously should not be required. It is therefore recommended

to maintain current levels of detailing that have been determined

by the local engineering profession.

23
3.4 Comments by ATC Representative on Ballot Items

April 9, 1980

Bruce Ellingwood

Secretary Committee 1 National Bureau of Standards

Washington, D.C. 20234

Responses to Comments on ATC-3 Seismic Criteria

These responses are each keyed to the written comments as they are made:

1) Letter to Ellingwood from Spellman dated 1-8-80. This letter recommends

contours instead of county boundaries on the seismic map. With the

exception of the western states county boundaries do not present a hardship. The use of contours presents some difficulties in interpretation

in coastal areas as presently drawn. Interpolation would require either

closure or extensive continuation of contours. Recognition of the problems of large counties with varying seismicity was specifically allowed

for in the ATC-3 guidelines with the alternate interpretation for section

1.4.1 on page 29. County boundaries also recognize human nature for what

it is. Pressure may be brought to bear to reduce criteria (e.g. other

comments on the provisions) but little will be brought to raise them. I feel sure that if ATC-3 were adopted eastern San Bernadino County, for

example, would quickly adapt to the real seismic hazard by invoking the

alternate 1.4.1.

Additional data will ultimately result in map changes but these must be

represented by considering the potential activity and the associated

risk rates. Maximum events are only a small part of the total input for

the maps.

2) Letter to Algernissen from Spellman dated 1-9-80. I am opposed to this

change. Fault activity using such a definition as that recommended makes

no distinction between a fault which may move 20 feet in an event and one which may move a fraction of an inch. Controversial and insufficient

definitions should not be part of a code- type document.

24
*\ National Bureau of Standards

April 10, 1980

Page two

3) Portland Cement Association - Mark Fintel - January 1980. The PCA

comments suggest that because the indices and the performance categories

have been "arbitrarily interrelated" they can also be arbitrarily reduced.

Codes developed by "consensus" are usually codes developed during quies- cence and are unlikely to sufficiently represent rare hazards. The

seismicity index numbers are to a large measure the province of Committee

2 but I do not see justification for their reduction.

4) Comments from committee on masonry - undated. These comments appear

to be particularly abrasive. In addition they are incorrect. The seismicity of map area 1 ranges between an EPA at zero to 0.04. Admittedly

large areas of some states have very low values. It was the ATC-3 viewpoint that any well designed structure can resist a lateral force based

on the ATC-3 criteria with an Aa value of 0.05 without penalty. The

masonry committee comments agree with this statement and want the re- quirements removed! The EPA value for map area is 0.05 or greater. As

with item 3 the modifications to Table 1-A are the province of Committee

2 .

5) Comments by Technical Committee 4 - dated January 31, 1980. My interpretation of the map places Phoenix in Maricopa County on Map Area

Number 4 on Figure 2 or Seismicity Index 3. This requires the detailing

for category C buildings. Detailing may well increase design costs while

improving performance. It would appear that fee negotiation is more

necessary than a reduction of criteria.

These comments represent my personal views but these have been considerably

tempered by the years of active involvement in the development of and the

innumerable compromises that had to be made before the ATC-3 guidelines

were released.

Sincerely

Neville C. Donovan

NCD:mb

cc: R.L. Sharpe

S.T. Algermissen

25
NBS-114A (rev. 2-hc) U.S. DEPT. OF COMM. 1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

SHEET (See instructions) NBSIR 80-2111vl October 1980

4. TITLE AND SUBTITLE

REVIEW AND REFINEMENT OF ATC 3-06 TENTATIVE SEISMIC PROVISION!

Report of Technical Committee 1: Seismic Risk Maps

5. AUTHOR(S)

Bruce R. Ellingwood

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions) 7. Contract/Grant No. NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234 Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, ZIP)

Federal Emergency Management Agency

Washington, D.C. 20472

10. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

b i bliography or literature survey, mention it here) The TENTATIVE PROVISIONS FOR THE DEVELOPMENT OF SEISMIC REGULATIONS FOR BUILDINGS

were developed by the Applied Technology Council to present, in one comprehensive

document, current state-of-knowledge pertaining to seismic engineering of buildings.

The TENTATIVE PROVISIONS are in the process of being assessed by the building com- munity. This report is one of a series of reports that documents the deliberations

of a group of professionals jointly selected by the Building Seismic Safety Council

and the National Bureau of Standards and charged with reviewing the TENTATIVE

PROVISIONS prior to the conduct of trial designs. The report contains the recom- mendations and records of the committee charged with review of the seismic risk maps,

'"he committee made 4 recommendations for revisions to the TENTATIVE PROVISIONS.

These recommendations were made to the parent group, the Joint Committee on Review

and Refinement, and their action on these recommendations is documented in a companion report.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Buildings; buildings (codes); buildings (design);

standards; structural engineering

13. availability

earthquake; seismic risk maps;

14. NO. OF

PRINTED PAGES

I y | Uni imited For Official Distribution. Do Not Release to NTIS

”j Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

28

15. Price

[jf] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

USCOMM-DC S043-P80