NBSIR 73-126

Structural Tests of Mechanical

Connections For Concrete Panels

L. E. Cattaneo and F. Y. Yokel

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20410

November 1972

Final Report

Prepared for Office of Research and Technology

Department of Housing and Urban Development

Washington, D. C. 20410

NBSIR 73-126

STRUCTURAL TESTS OF MECHANICAL

CONNECTIONS FOR CONCRETE PANELS

L. E. Cattaneo and F. Y. Yokel

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

November 1972

Final Report

Prepared for Office of Research and Technology

Department of Housing and Urban Development

Washington, D. C. 20410

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts. Director

Table of Contents

Structural Tests of Mechanical Connections for Concrete Panels

Page

Abs tract

SI Conversion Units

1.0 Introduction and Objective 1

2.0 Description of Building System . . . 2

3.0 Scope 3

4 . 0 Speci mens 5

4.1 Connectors , 5

4.2 Fabrication of Specimens 6

5.0 Test Apparatus and Procedures ... 10

5.1 Bolt Tensioning 10

5.2 Specimen Loading 10

5.3 Displacement Measurements 11

5.4 Test Procedures 11

6.0 Discussion of Test Results 12

6.1 Type A Floor Connection Elements 12

6.2 Type B Floor Connection Elements 14

6.2.1 General Discussion 14

6.2.2 Tension 16

6.2.3 Vertical ( out- of - p 1 ane ) Shear 17

6.2.4 Horizontal (in-plane) Shear 18

6.3 Type E Wall Connection Elements 20

6.4 Type F Wall Connection Elements 22

6.5 Type D Wall Connection Elements 22

7 . 0 Summa ry . . .

• 24

References 27

Tables 28

Figures 34

Appendix - Test Results

structural Tests of Mechanical

f 0 r Concrete Panels

Connections

by

L. E. Cattaneo and F. Y. Yokel

Structures, Materials and Life Safety Division

Center for Building Technology

Institute for Applied Technology

ABSTRACT

Structural evaluation tests were performed on prototype

steel insert connectors proposed for joining floor and wall

panels of a precast concrete housing system included in Operation BREAKTHROUGH. Descriptions are given of 25 tests conducted

with 5 different types of connectors. Specimen connections

were 1 abora tory- tes ted under simulated design loading conditions to evaluate their load capacity and ductility.

Key words: Concrete panels; connections; ductility; floor

diaphragms; housing systems; insert connectors;

Operation BREAKTHROUGH; precast concrete.

i
SI CONVERSION UNITS

In view of present accepted practice in this country in

this technological area, common U.S. units of measurement have

been used throughout this paper. In recognition of the position

of the USA as a signatory to the General Conference on Weights

and Measures, which gave official status to the metric SI system of units in 1960, we assist readers interested in making

use of the coherent system of SI units, by giving conversion

factors applicable to U.S. units used in this report.

Length

1 i n = 0.0254* meter

1 ft = 0.3048* meter

Area

1 in^ = 6.4516* x 10"^ meter^

1 ft^ = 0.09290 meter^

Force

1 lb ( 1 bf ) = 4.448 newton

1 kip = 4448 newton

P res s u re , Stress

2

1 psi = 6895 newton/meter

Mass/Volume

1 Ib/ft^ (Ibm/ft^) = 16.02 kilogram/meter^

Temperature °C = 5/9 (Temperature °F - 32)

*Exactly

i i
structural Tests of Mechan ical Connections

for

Concrete Pane Is

by

L. E. Cattaneo and F Y. Yokel

1.0 Introduction and Ob j ect i ve

This report presents the results of tests performed to

assist in the structural evaluation of a housing system selected by the Department of Housing and Urban Development for the

Operation BREAKTHROUGH Program. The tests were conducted by

the Center for Building Technology of the National Bureau of

Standards as part of the technical support provided to DHUD.

The objective of the tests was to provide information

necessary for evaluating the load capacity and ductility of a pre-cast concrete system using large panels.

An innovative feature of this system is the use of bolted

steel connection elements of several standardized forms. The

joint between two or more panels uses a sufficient number of

connection elements to achieve the desired load capacity. Thus

a single connection element may be considered to play a role

similar to that of a single bolt in a bolted joint.

To insure adequate load capacity of the building structure

it was essential to have reliable information on the load capacity of the connection elements. Because of the critical
importance of this information and the complexity of the structural interaction, proof testing had to be used to verify the

calculated strength of the connections and to obtain information on the characteristics of their resistance function.

2.0 Description of Building System

Figure 1.2.1 shows a simplified diagram of the structural

system. The wall and floor panels are assembled at the site

into structures which can range from 2-story townhouses to

high-rise apartment buildings. Typical wall panels are approximately 30 ft X 8 ft X 8 in and contain vertical reinforcing

bars (varying between Nos. 4 and 6)[1]-^ and welded wire fabric

(4 X 4 - W4 X W4)[2] in each face. The perimeters of the wall

panels contain pairs of bars (varying between Nos. 5 and 8)

and, in addition, the top and bottom edges contain No. 4 bar

stirrups. Typical floor slabs are approximately 22 ft x 10 ft

X 5 in and contain welded wire fabric (4 x 8 - W4 x W4 ) in the

top surface and 1/2-in diameter prestressing strands in the

bottom, spaced at about 6 in, on center, across the width.

Elevator cores, stairwells, etc., assembled on-site from precast elements complete the component mix required in a typical

building.

Joining of the structural panels is accomplished by means

of steel insert connectors cast into the edges of the panels.

IT

Numbers in brackets indicate references listed at the end of

this report.

2
High strength bolts and special washers complete the connections which are subsequently grouted. The locations of the

various types of connections are shown generally in figure

1.2.1; details of the various connection elements and supplementary hardware are given in figures 1.2.2 through 1.2.8.

Photographs of the 5 types of insert connectors (identified

in this report as A, B, D, E and F) submitted for test are

shown in figures 1.2.9 through 1.2.13. A close-up of a floorslab to floor-slab (Type B) connection is shown in figure

1.2.14. Figure 1.2.15 further illustrates (as it would appear

with concrete removed) the relationship of a Type ^ floor insert to Types E and F wall inserts at the connection of a floor

slab with exterior bearing wall panels. It should be noted

that, in order to implement design changes, some inserts were

modified between the time of receipt at the laboratory (photos

in figs. 1.2.11 through 1.2.13) and the time of testing (drawings in figs. 1.2.4 through 1.2.6). These modifications are

described in section 4.1 (Connectors).

3 . 0 Scope

This report documents tension tests and shear tests performed to determine the load capacity and ductility of 3 basic

connection designs which make use of the 5 types of insert

connectors.

3
The three connections (and respective inserts) are:

a. Floor-slab to bearing-wall to floor-slab.

(Inserts : A to D to A)

b. Floor-slab to floor-slab (unsupported edges).

(Inserts: B to B)

c. Junction of bea ri ng-wal 1 - top to wall-bottom, with

floor-slab to floor-slab.

(Inserts : E to F , A t o E t o A

A total of 25 tests were performed (see table 3.0) and

are presented in 7 groups which are listed below:

a. Tests 1, 2: In-plane tension on floor

' connection element (Type A) used over

bearing wal 1 s .

b. Tests 3, 4: In-plane tension on floor connection

element (Type B) used in unsupported

edges

c. Tests 5, 6: Out-of-plane shear of floor-slab to floorslab connection (Type B)

d. Tests 7-13: In-plane shear of floor-slab to floorslabconnection(TypeB)

e. Tests 14-16: In-plane tension on wall top connection

' element (Type E)

f. Tests 17-19: In-plane tension on wall bottom connection element (Type F)

g. Tests 20-25: Out-of-plane shear of bearing wall top

connectionelement(TypeD).

4
4.0 Speci mens

4.1 Connectors

Insert connectors and ancillary hardware used in the tests

were supplied by the housing system producer. Details of these

parts as used in test specimens which simulated wall and

floor panel connections are shown in figures 1.2.2 through

1.2.8. It should be noted that some of the inserts as tested

(shown in figs. 1.2.4 through 1.2.6) differ in some respects

from the corresponding photographs (1.2.11 through 1.2.13) of

the inserts as received. These modifications were made so that

the insert connectors would conform to the design changes in

effect at the time of testing. Those affected were:

a. Type D - Anchor bars were shortened from 24 in to

18 in . (fi gs . 1.2.4, 1.2.11).

b. Type E - Two end-pairs of anchor bars were removed and

base plate was shortened from 2 ft-3 in to

2 ft; remaining 6 anchor bars were shortened

from 2 ft-6 in to 2 ft; spacing of bars was

left at 6 in although new spacing is to be

8 in. (figs. 1 .2.5, 1 .2.12) .

c. Type F - Same as for Type D (above); (figs. 1.2.6,

1.2.13).

Furthermore, the Type A test inserts had been fabricated of

7/16-in thick rectangular tubing (instead of 1/2-in, as designed) because of unavailability of the 1/2-in material.

5
All base welds of shear studs and bar anchors were examined

visually for obvious defects that would interfere with their

intended function. One Type A insert was discarded as a result

of one bar anchor breaking off in handling during this inspection. Further examination of weld quality was conducted by

performing cold bend tests [3] on all base welds of 3 Type A

and 5 Type B insert connectors. These were chosen at random

as a sample of stud welds and bar welds from among the 82

various insert connectors received. Using this cold bend test

method, studs and bars on the samples were bent through an angle

of 30° by striking with a hand hammer and then back to the

original position in the same manner. Only one weld failure

occurred. One bar anchor (Type A insert) was broken off completely after several hammer blows. No other base weld which

was tested showed any apparent sign of failure.

4.2 Fabrication of Specimens

Specimens of floor slabs and wall panels were fabricated

in the testing laboratory in accordance with plans and specifications provided by, or modified in consultation with, the housin

system producer. All floor and wall panel specimens were cast

in a horizontal plane. Drawings, giving a general description

of the specimen dimensions with size and location of reinforcement, are shown in figures 2.2,1 through 2.2.6. Figures 2.2.1

through 2.2.3 describe the specimens which were fabricated

according to the original design; and figures 2.2.4 through

2.2.6, show specimens using the modified design. Specimens of
the design shown in figures 2.2.4 and 2.2.5 used a modified

reinforcing detail to better simulate the restraint of prestressing. Specimens of the design snown in figure 2.2.6 were

added to the test series to simulate a special condition requiring test evaluation; in these the insert (Type B) is situated close to a corner of a floor slab, 8 in from the side of

a utility cut-out (see insert in figure 1.2.1 connected to

labeled example of a typical Type B). The reinforcement in the

specimens shown in figures 2.2.4 through 2.2.5 was considered

reasonably representative of prototype construction.

Main reinforcement used in the panel specimens consisted

of No. 3, No. 4 and No. 5 bars of ASTM A-515-70 Grade 50 [1]

deformed steel bars. Welded steel wire fabric specified for

concrete reinforcement was of two sizes: 4 x 4-W4 x W4 and

4 x 8-W4 x W4 (ASTM A- 1 85- 70 ) [2 ] . Covers for protecting insert tube cavities and other blockouts during casting (for later access to connecting nuts and

bolts) were formed of plywood (fig. 2.2.7).

Concrete for the specimens was mixed at the laboratory in

an 8-cu yd commercial transit mixer in 2- or 3-cu yd batcnes,

and consolidated in forms and molds with internal vibration.

All batches were made with type I cement and normal weight sand

and gravel; the maximum aggregate size was 3/4 in and the air

content which was specified to be 3 percent, or less, did not

exceed 3.7 percent. The properties of the concrete batches at

the time of casting are given in table 4.2. The concrete batch

7
number is also used as the last digit of the specimen identification number (Table 3.0). The concrete mixes were proportioned as recommended by the supplier to achieve the desired

strengths and the specified slump of 2 in + 1 in. Concrete

for specimens representing floor slabs was specified to have

a compressive strength of 5000 psi at 28 days and contained

6 bags of cement, 1200 lb of sand and 1900 lb of gravel per

cu yd (with allowance for moisture in the aggregate); wall

panel specimens were specified to have a 28-day compressive

strength of 4000 psi and were made of a mix containing 5 bags

of cement, 1280 lb of sand and 1900 lb of gravel per cu yd.

Control cylinders (6 in x 12 in) for compression testing according to ASTM Method C-39-71 [4] were cast for all batches. All

cylinder test specimens were consolidated in their molds by

internal vibration. After removal from forms and molds all

specimens were moist-cured at 73° F, 95% R.H. until they reached

the desired strength as indicated by cylinder tests. Specimens

were then stored in the laboratory at 73° F, 50% R.H. until

tested. Concrete strength at the time of panel tests was

determined by cylinder tests (table 3.0).

Where connections were made in order to perform tests on assemblages of bol t- connected specimens (or to simulate such

connections by attachment of loading equipment), bolts were

tensioned to the specified load value with a calibrated torque

wrench (fig. 2.2.8). Type B floor-slab to floor-slab connections which used 3/4-in x 3 1/2-in ASTM A-325[5] bolts were

8
tightened to a bolt tension of 100 percent of proof load

(28,400 lb). Floor-slab to wall-panel to floor-slab connections (Type A to D to A) which used 3/4-in x 5-in A-325 bolts

were tightened to a bolt tension of 5 percent of proof load

(1420 lb). Bearing wall top and bearing wall bottom connections

(Types E and F) which used 5/8-in A-325 stud bolts (or equivalent bolts for testing Type F) were tightened to a bolt tension

of 5 percent of proof load (960 lb). Joint spaces of 1/4 in

were achieved using steel shims (figs. 1.2.7, 1.2.8, 1.2.14).

In the actual system these spaces are used to compensate for

tolerances in typical connections.

Grouting of joints and block-outs (and insert tube

cavities in some test specimens) was done with a proprietary

product. It is described by the manufacturer to be a factorymixed, non - s h ri n k i n g , non-corrosive grouting material which

contains Type III portland cement, sand and additional proprietary aggregate. The grout was mixed in accordance with

the manufacturer's directions to attain compressive strength

in excess of that of the specimen concrete. It was placed by

hand. At the time of testing the connection element, checks

were made on the grout compressive strength using 2-in cubes

stored in the laboratory alongside the grouted test specimens

(table 3.0). Grout cubes were prepared and tested according

to ASTM Method C-1 09-70T[ 6] . Prior to testing, connection element specimens were whitewashed to increase visibility of test damage.

9
5.0 Test Apparatus and Procedures

Much of the apparatus and test procedure were common to

many tests and are described here in general; comments on individual test particulars are included in the Appendix (Test

Results) under the enumerated tests.

5.1 Bolt Tensioning '

In order to tension the connection bolts to the proper

loads, a hand-indicator-torque wrench (fig. 2.2.8) was calibrated to determine the torque corresponding to the desired

bolt tensions. This operation was performed on sample groups

of 3 bolts for each combination of bolt size and load. Calibration loads were measured by a center-hole type of load cell

clamped between the head and nut (with appropriate washers)

of each sample bolt while torque was measured on the wrench

dial indicator. Calibration was performed with an extension

attached to the socket end of the wrench which, later, had to

be used in order to gain access to connecting bolts within

insert cavities (fig. 2.2.8).

5.2 Specimen Loading

Specimens were subjected to loads applied by hydraulic

rams. Center-hole-design rams, with a pull-rod through the

ram bearing on a yoke beam, (fig. 3.2.1) were used to apply

static tensile loads. Specimens subjected to static compres10
sion were loaded by rams reacting against structural frames

attached to the structural laboratory tie-down test floor

(fig. 3.2.2). Repeated shear (push and push-pull) tests were

performed in a closed reaction frame with rams controlled by

electro-hydraulic servovalves actuated by a signal function

generator (fig. 3.2.3). Pressure for static rams was supplied

by manual pumps and that for repeated load tests by a motor

driven hydraulic power supply. All loads were measured by load

cells (center-hole type, where required) placed in line with

the rams

5.3 Displacement Measurements

Linear variable differential transformers (LVDT's) were

used for the measurement of deformation in specimens and of

displacement between parts of test assemblages. LVDT's were

mounted on fixtures attached to specimens with hot-melt adhesive

as shown in figure 3.2.1. For correlation of test photographs

which illustrate displacement measurement with test load-displacement computer plots, it is to be noted that specimen movement causing LVDT core insertion into the coil produced a positive record of displacement; and extraction, a negative one.

5.4 Test Procedures

In general, manually pumped static loads were applied

at a rate of approximately 2000 Ib/min in increments of 1000

lb or 2000 lb (depending on the expected maximum). Load increments were followed by brief pauses (of seconds duration)

11
to record 2 to 5 load-displacement observations. Voltage

signals from transducers were automatically measured and recorded

on magnetic tape for computer processing to produce digital

data and computer-plotted graphs. Tests were also monitored,

for the purpose of progress control , by an X-Y recorder actuated

by one load cell and one LVDT.

Repeated load tests (Tests 12 and 13 only), which employed

cyclic loading, subjected the specimens to sinusoidal load at

a frequency of 0.1 Hz. Load cell and LVDT signal outputs were

recorded continuously on strip chart recorders.

2 / 6.0 Discussion of Test Results—

6.1 Type A Floor Connection Elements

Type A elements connect floor panels to bearing wall panels.

Two of these elements were tested in tension, their critical

mode of loading (Tests 1 and 2).

In Test 1 (fig. 4.1.1) the element was embedded in a floor

slab specimen using the revised design (fig. 2.2.4) which gave

less restraint and was thought to be a more accurate simulation

of actual conditions than the original specimen design. Typical

resistance curves are shown in figures 4.1.2 and 4.1.3 which

illustrate the load-displacement relationship for Test 1. In

Test 2 the original specimen design (fig. 2.2.1) was used.

27

For details on tests, reference is made to table 3.0 and the

text in the Appendix.

12
Another difference between the specimens was that the insert

tube was filled with grout in Test 2.

The large difference between the failure loads in these

two tests (29.5 kip in Test 1 versus 38.7 kip in Test 2) is

probably attributable to differences in the reinforcement

design.

Failure load is defined as the load at which the specimen

ceases to fullfill its function which, in this particular case,

would be the yield load. It should be distinguished from

ultimate load, which is the maximum load the specimen could

resist, and rupture load which occurred at a point beyond

which the specimen lost the ability to resist load.

The hairpin bars in the Test 2 specimen, shown in figure

2.2.1, provided more restraint to the wing studs than the

reinforcing bars used in the Test 1 specimen, shown in figure

2.2.4. The failure mode of these specimens (figs. 4.1.1 and

4.1.4) illustrates the important role of the wing studs and

the potential effect of their confinement, since in both cases

the concrete covering the wing studs failed. In figure 4.1.4

the specimen was "pulled away" after rupture of the tail

anchors to better examine their condition. It can be seen in

figure 1.2.2 that the concrete cover of these studs was only

1 1/2 in. Another factor that may have affected capacity was

the grouting of the connector tube. However, although the Test

2 specimen was grouted, it is questionable whether this grout

did increase its capacity since no deformation had been observed

1 3
in the ungrouted tube of the Test 1 specimen. On the basis

that the less confining reinforcement in the Test 1 specimen

is considered a better simulation of the actual structure, the

results of Test 1 are considered representative of the strength

of the Type A connection element in tension.

The ductile behavior of both specimens (more than 1/4-in

elongation after the failure load was reached is probably

attributable to localized plastic deformation in the tail

anchor bars. Tensile failure in the tail anchor bars was

observed in both specimens.

6.2 Type B Floor Connection Elements

6.2.1 General Discussion

Type B elements are used to connect floor panels to each

other. They are subjected to horizontal (in-plane) shear or

tension when the floor acts as a diaphragm to transmit horizontal (wind and earthquake) loads; and to vertical ( out-of -pi ane

shear when two adjacent floor panels are subjected to different

live loads or when adjacent panels have to be forced into align^

ment during erection.

Type B elements use oversize bolt holes and depend on friction bolting to develop shear resistance (the proof load on

the bolts is 28,400 lb). Overcoming of this frictional resistance as identified by sudden marked initial slip defines shear

failure of Type B connectors. The conclusions drawn from the

results of this test program are based on two premises: (1)

14
the tightening of the bolts does not exert significant tension

on the connection elements; (2) the proof load in the bolt is

fully transmitted as compression through the bearing between

two adjacent elements.

Lack of fit (contact) in this bearing prior to tensioning

of the bolt could result in a situation where part of the tension force in the bolt is resisted by tension exerted on the

slabs by the connectors. Only the remaining part of the bolt

tension force would then be available to compress the bearing

between the two connectors. As a result, the capacity of the

connection element in all three modes of loading previously

discussed would be reduced.

Such a situation was experienced in the first unsuccessful

attempt to assemble a floor-joint specimen assemblage (of the

type described in Appendix section A. 1.4, Test 7). Contact

between the floor slabs at points besides the inserts, in addition to insufficient shimming between the connection insert

bearing surfaces, allowed the tensioning force to produce

separation cracks between the concrete and the insert tubes.

The designer intended to use steel shims to compensate for

any lack of fit. It was not one of the objectives of the

investigation to determine the feasibility of achieving full

bearing prior to tensioning of the bolt or to make specific

recommendations for added safety margins required to allow for

erection tolerances.

1 5
6.2.2 Tension

Tests 3 and 4 (figs. 4,1.5, 4.1.6, and 4.1.7) were tension

tests on Type B connection elements. The specimen in Test 3

used the revised slab specimen reinforcement design (fig. 2.2.5)

while in Test 4 the original design (fig. 2.2.1) was used.

Test 3 used no grout and in Test 4 the tube of the connector

was filled with grout.

As in the case of the Type A connection elements, the

specimen using the revised reinforcement design (Test 3) failed

at a lower load (18.0 kip as compared to 30.0 kip for Test 4).

The failure of these specimens was ductile. In this case, the

wing studs had substantial concrete cover. Grouting may have

affected strength; however, the failure modes provide no evidence

that this was the case (no distortion of the tube in the ungrouted specimen was observed).

Figure 4.1.5 and 4.1.7 illustrate the failure mode. There

was a tensile failure in the tail stud as is illustrated by the

typical load-displacement curve shown in figure 4.1.6. The wing

studs were bent but did not rupture.

The failure load in Test 3 should be considered indicative

of the load capacity of the connection element since the Test 3

specimen better simulated restraint of the anchor in the

structure.

16
6.2.3 Vertical ( out-of-pl ane ) Shear

Two specimens were tested (Tests 5 and 6). The Test 5 specimen (fig. 4.1.8) used the revised reinforcement detail

(figure 2.2.5) and in the Test 6 specimen the original design

(fig. 2.2.1) was used. While the Test 5 specimen was ungrouted,

grout was used in the tubes and the joints of the Test 6 specimen. Another difference was in the test set-up. Test 5 used

restrained support conditions, (fig. 4.1.8). In Test 6 the

outer slabs were unrestrained (as shown in fig. 4.1.10) and

could rotate. In the actual structures, individual floor slabs

are only partially restrained from rotation and grouting of the

joint might not be used. Test 5 is considered the simulation

which provides an i'ndication of the connection element strength

with less risk.

Since failure occurred by slipping at the interface between two adjacent connectors, it is assumed that the confining

reinforcement arrangement had no effect on load capacity. However, load capacity was probably affected by grouting and may

have been affected by support conditions.

Figure 4.1.9 shows the plot of slip versus load for Test

5 which is also similar to the response observed in Test 6. It

can be seen that a large displacement occurred after initial

slip. This apparent yield is attributable to slipping of the

connection elements. The subsequent load increase occurred

when the bolt resisted additional slipping in shear. The plot

does not show the entire range of the test in which the speci17
men resisted an ultimate load of 24 kip. Extended failure

damage, as illustrated in figures 4.1.8 and 4.1.10, occurred

by spalling of the concrete covering the connectors. This mode

of failure was resisted by the welded wire fabric covering the

connector.

In summary. Test 5 with a failure load of 14.5 kip is

considered a more reasonable representation of prototype construction. Both specimens developed approximately equal maximum loads.

6.2.4 Horizontal (in-plane) Shear

The loading condition simulated by these tests is considered critical since the connection element participates in the

transmission of wind and seismic loads to the shear walls.

The Test 7 specimen (fig. 4.1.11) contained the revised

reinforcement design (fig. 2.2.5) and no grout. The Test 9

specimen contained the revised reinforcement design and grout

in the connector tubes but not in the joints. Tests 10 and 11

used specimens similar to those in Tests 7 and 9, respectively,

except that the connector was located close to the corner of

the slab simulating a critical design condition. Test 8 used

the original design (fig. 2.2.1) and grouting of the tubes as

well as the joints. Test 10 is considered the simulation which

would be expected to provide the least strength. However, the

variables in Tests 7, 9, 10 and 11 apparently did not affect

load resistance.

18
A typical resistance curve is shown in figure 4.1.12 which

illustrates the load-displacement relationship for Test 7. Up

to 10.0 kip the load was resisted by the friction force.

Subsequently, large deformations were associated with additional

loading. The 10-kip load is identified as the failure load.

The ultimate load is 34.5 kip. Collapse occurred by shearing

of the high-strength bolt, (see figures 4.1.11 and 4.1.13).

No concrete failure was observed in Tests 7 through 9. In Tests

10 and n, where the connector is located close to a corner, the

concrete was sheared in addition to the connections failing

by slip as shown in figures 4.1.14, 4.1.15, 4.1.16 and 4.1.17.

In Test 11 the bolt was sheared in addition to the concrete

failure, while the Test 10 specimen reached ultimate load by

shearing of the concrete without fracture of the bolt. In

spite of the differences in their failure modes the resistance

curves, as well as the failure loads and maximum loads, are

similar in Tests 7, 9, 10 and 11. Test 8, which used grout in

the tubes and joints, developed a much higher frictional resistance; however, the maximum load was similar to that of the

other test specimens. Since the integrity of grout in joints

like those in Test 8 can not be assured because of their small

widths, and since grouting might not be used in all cases, it

is concluded that the results of Tests 7, 9, 10 and 11 give

an indication of the load capacity of the connection element.

Even though the failure loads of specimens 7, 9, 10 and

11 are similar, it may be desirable to prevent the concrete

19
failure observed in Tests 10 and 11 (see figs. 4.1.14 through

4.1.17) by additional reinforcement designed to prevent diagonal

tens i on cracks , Another two tests were conducted with specimens similar

to the one used in Test 7 applying repeated cycles of load

(fig. 4.1.18). In Test 12, 1000 cycles of 3.8 kip per connection

were applied. This cyclic load was determined to represent

50 percent of the design windload acting on a connection whose

load capacity (10 kip) would be fully utilized to resist extreme

wi ndl oads

In Test 13, five alternating cycles of 5.9 kip per connection were applied. The 6.9 kip load was determined to represent

the design seismic load acting on a connection whose load

capacity would be fully utilized to resist extreme seismic load.

In both cases the sinusoidal load had a frequency of 0.1 Hz.

No slip failure or distress was observed.

6.3 Type E Wall Connection Elements

Type E connection elements are used to provide structural

continuity (transmit tensile forces) between two successive

bearing wall panels. Type E connection elements are also

designed to provide a wa 1 1 - to- f 1 oor connection together with

Type A connectors.

The critical loading of these connection elements is

tension caused by uplift forces, or by gravity following the

destruction of a bearing wall panel by catastrophic loads. In

20
the latter case the connector would act to prevent progressive

3 / collapse— as a result of abnormal loads on the building.

Three identical specimens were tested under similar loading conditions in Tests 14, 15, and 16. Figure 4.2.1 shows the

setup for Test 14. Tension was applied through nuts attached

to the high strength stud bolts . Displacements were measured

between the concrete panel and the base plate of the connector.

Displacements observed in this test were very small and failure

occurred by rupture of the bolts (fig. 4.2.2). In subsequent

tests, displacement measurements were made of bolt elongation

(as shown in fig. 4.2.3 for Test 15). Figure 4.2.4 shows the

results of Test 15 and figure 4.2.5 shows the setup for Test

16 in which both displacement of base plate and bolt elongation

were measured. The failure in Test 16 is shown in figure 4.2.6.

Typical measurements are plotted in figures 4.2.7 and 4.2.8

for bolt elongation in Test 16; and in figures 4.2.9 and 4.2.10

for base plate displacement in the same test. The connection

elements in all three tests developed tensile load capacities

ranging from 55 kip to 58 kip. In all three, failure by

fracture occurred with very little elongation of the high

strength bolts (approximately 0.04 in). In establishing allowable design loads for these connection elements allowance should

be made for their lack of ductility.

—The term "progressive collapse" is used to describe a chain

reaction of failures in a structure initiated by failure of

a localized portion of the structure.

21
I

6.4 Type F Wall Connection Elements

Type F elements connect to Type E elements and therefore

fulfill the same function in tension. Thus the capacity of the

connection in tension must be controlled by the weaker of the

! two elements. Three tests were performed. In Test 17 (fig.

4.2.11) the connection element was not grouted. In Tests 18 and

19 (figs. 4.2.12 and 4.2.13) similar grouted specimens were

used. In all cases failure occurred in the connecting bolts

which actually simulated the mating bolts of a Type E element.

Except for minor concrete cracking no other distress was

observed. The lowest load capacity was observed in Test 17

where failure was caused by thread stripping in both nuts (fig.

4.2.11). Unless design provisions are made to prevent thread

failure, the lower load capacity in this test controls the

allowable tensile load on the joint composed of Types E and F elements.

6.5 Type D Wall Connection Elements I

Type D wall connection elements are used together with

Type A floor elements to effect a connection between floor

slabs and bearing wall panels. These elements were judged to

be critical in the prevention of progressive collapse in locations where wall panels or portions of wall panels would be

required to resist extreme lateral (out-of-pl ane ) loads. Thus

the capacity of these connections under shear acting normal

to the plane of the wall had to be determined.

22
A total of six tests were conducted on three specimens.

Figure 4.2.14 shows the specimen used in Tests 20 and 21.

Initially, load was applied by both rams; however only one

connection failed. Subsequently the other connection was loaded to failure. This procedure generated two tests for the

first specimen. In subsequent specimens, tests were conducted

sequentially on one end and then on the other.

In Test 20 the load reacted on large steel plates as shown

in figure 4.2.14. It was determined from the failure mode

(fig. 4.2.15) that this provided restraint to the concrete and

thereby increased load resistance. Thus, the results of Tests

20 and 21 are high and do not represent a valid simulation.

In subsequent tests the load was applied through smaller, less

confining bearing plates as shown in figure 4.2.16 for Test 22.

Load versus displacement is given for Test 22 in figure

4.2.17. Static load was applied in 4-kip increments and reduced to zero after each new increment. The trend in this plot

is also typical of that for the other tests. Failure load in

this test was determined at the point where significant distress

was observed in the concrete surface of the wall. This distress

coincided with a marked change in the slope of the loaddisplacement curve. Subsequently, large additional deformations

occurred during gradual shear failure in the concrete. The

ultimate load substantially exceeded the failure load. The

load capacity of these connection elements provided information

which is important when progressive collapse is considered.

23
Figure 4.2.18 shows the failure mode in Test 23. Failure

modes in Tests 24 and 25 are shown in Figures 4.2.19 and 4.2.20,

respectively. In each case considerable spalling of concrete

can be observed.

Comparison of the test results indicates that except for

Tests 20 and 21 (which are not considered valid simulations)

failure loads and ultimate loads are reasonably consistent.

Grout was used only in the specimens in Tests 20 through 23.

Grouting had no apparent effect on load capacity or loaddisplacement characteristics.

7.0 S umma ry

These tests were conducted because of the critical nature

of the function of the connection elements. Results were obtained to assist in determining the load capacity and ductility

of a pre-cast concrete panel system. In tests of Type B connection elements in in-plane shear. Types E and F in tension,

and Type D in out-of-plane shear, several similar specimens

were tested under similar loading conditions. In all other

cases only a single test is considered representative of the

design used. Even where several specimens were tested, the

number of tests performed was not adequate to determine strength

variability. Thus, none of these test results should be used

as a basis for increasing design load capacities if they are

above those determined by calculation. Additional testing

would be necessary for this purpose.

24
Table 7.1 lists the minimum capacities determined from

those tests which are considered reasonable simulations of the

most critical design conditions. In the case of connection

elements Types E and F, where the weaker of the two constitutes

the weak link in the connection, only the lowest value from all

the tests of Types E and F elements is listed.

In addition to the lowest test results, table 7.1 notes

whether the failure was ductile. Ductile behavior would tend

to allow the structure to fail only if several connection

elements fail simultaneously. In the case of nonductile failure, a single element could act as a weak link. Thus, conservative margins of safety should be used for nonductile connection

elements, notably Types E and F. On the other hand the ductile

behavior of the other connection elements could be exploited

in earthquake resistant design.

In the case of Type B elements the results shown in table

7.1 are qualified, since they are based on the assumption that

a fit of the bearing interface is achieved prior to tensioning

of the friction bolt. Lack of fit at the bearing interface of

these connection elements could result in reduction of their

load capacity.

For the case using Type B elements simulated in Tests 10

and 11, an improved arrangement of reinforcement in the vicinity of the connection would prevent shear failure of the concrete near the corner of the slab.

25
The minimum capacities listed in table 7.1 are based on

the assumption that tolerances in fabrication and erection are

within the limits recommended by ACI Standard 314-65[7] and

ACI Standard 318-71[8]. It was not one of the objectives of

this investigation to determine the feasibility of compliance

with this standard.

26
References

1. American Society for Testing and Materials, Specification

A-615-68 for Deformed Billet-Steel Bars for Concrete Reinforcement, Part 4 of Book of 1971 ASTM Standards, Philadelphia, Pa.

2. American Society for Testing and Materials, Specification

A-185-70 for Welded Steel Wire Fabric for Concrete Reinforcement, Part 4 of Book of 1971 ATMS Standards, Philadelphia, Pa.

3. American Welding Society, Code for Welding in Building

Construction (AWS Dl.0-69, Section 432), 1969, New York,

New York.

4. American Society for Testing and Materials, Test Method

C-39-71 for Compressive Strength of Cylindrical Concrete

Specimens, Part 10 of Book of 1971 ASTM Standards, Philadelphia, Pa.

5. American Society for Testing and Materials, Specification

A-325-70a for High-Strength Bolts for Structural Steel

Joints, Including Suitable Nuts and Plain Hardened Washers,

Part 4 of Book of 1971 ASTM Standards, Philadelphia, Pa.

6. American Society for Testing and Materials, Test Method

C-109-70T for Compressive Strength of Hydraulic Cement

Mortars (Using 2-in Cubes), Part 9 of Book of 1971 ASTM

Standards, Philadelphia, Pa.

7. American Concrete Institute, Manual of Standard Practice

for Detailing Reinforced Concrete Structures (ACI 315-65),

1965, Detroit, Michigan.

8. American Concrete Institute, Building Code Requirements for

Reinforced Concrete (ACI-31 8-71 ) , 1971, Detroit, Michigan.

2 7
remarks

Loaded

to

34

kip

max.

at

deformation

>0.27

in;

no

instability

of

Insert

tube

observed;

tensile

jilure

nf

one

tail

anchor

bar.

Loaded

to

48kip

max.

at

deformation

>0.28

in;

no

cracking

observed

in

grout

fill;

tensile

failure

of

both

tail

anchor

bars.

Loaded

to

22

kip

max.

at

deformation

>0.31

in;

no

instability

of

insert

tube

observed;

tensile

failure

of

tail

stud.

Loaded

to

42

kip

max.

at

deformation

>0.25

in;

grout

inside

insert

tube

not

cracked;

tensile

failure

of

tail

stud.

Loaded

to

24

kip/conn,

max;

total

deformation

of

0.11

in

slip

between

inserts

and

=i

3/4

in

shear

displacement

between

slabs;

restrained

support.

Loaded

to

25

kip/conn,

max

total

shear

deformation

between

slabs

of»l

in;

LVDT's

mounted

on

insert

grout

fill;

restrained

support. Loaded

to

34

.

5kip/conn

.

max.

at«0.45

in

total

deformation;

shear

failure

of

bolt.

Deformation

at

Failure

in

Loading

Direc

ti

on

(in) 0,

040

0.045 0.

040 0.

010

Initial slip

Initia

1

slip

Initial slip

Failure load

kip

/tone); •X

ON 38. 7 o

00 30.0

*

18.5

*

10. 0

Type of Test Loading Tens

i

on

Tens

ion

Tens

ion

Tens

ion

"ert

.

(O'lt-Of

plane;

Shear

' a u C IB

J- o rt (u

1 ^ .c

OJ i-> c/3

Hor

Iz

.

(In-plane) Shear

Bolt

Pre

-tensi

oo

(

lb)

1420 1420 284

00

28400 28400 28400 oo

o00

BoU

Diam. (in) vt

C--1

Type of Insert < < CQ CC

Grout

Strength Test

(psi) 0 (In

insert

)

5510 O

3

(In

insert

)

6140 w/o (In

joints

and

inserts) 7550 w/o

Cone

re

te

Strength at Test *v

PSi; 6540

OJo

o

o

\

6400

(Uo

o

o

A

6300 4860 6540

Reinf

.

Pesl

gn

-

Fig.

No. CO>

• bC , H CN U . o ^

Mu-I

•H . >fM

(U . OicN

. I—

1

01 . •H OJ U . O CNJ

CO in

•H . > .7M <U . (N

as. . •H CsJ

1-1 . O CN

Revis.) 2.

2.5

Test Figure Nos.

00 60

<t <r <^ 4.

1.4

00

-M CO ON

'n <t --t

o

tm

f-^ CN

Desc

r

ipt

.

of Connection Floor to

Wall Floor to

Hall

Floor toFloor F

loor to

Floor Floor to

Floor Floor to Floor Floor to

Floor

Specimen

Identification

1-116-7 I-lOl-l -^

1

1

li

1-208-7 a

1-207-7

Test No. m m

28
Remarks**

Loaded

to

33

kip/conn.

max.

at

>0.25

in

total

deformation;

shear

failure

of

bolt.

LVDT's

mounted

on

insert

tube

grout

fill.

Loaded

to

35.5

kip/conn,

max.

at

«0.95

in

total

deformation;

shear

failure

of

both

bolts;

LVDT's

mounted

on

insert

tube

grout

fill.

Loaded

to

33

kip/conn,

max.

at

*0.5

in

total

deformation;

multiple

cracks

around

racked

insert

tubes.

Loaded

to

30

kip/conn,

max.

at

>0.2

in

total

deformation;

LVDT's

mounted

on

insert

tube

grout

fill;

shear

failure

of

bolt.

Repeated

loading

caused

no

slip

in

either

connection.

Repeated

load

reversal

caused

no

slip

in

either

connection.

Def

ormat

i

on

at

Failure

in

Loading

Direc

tion

(In)

Initial slip Initial slip Initial slip

Init

ial

slip

None coz

Failure Load

(kip

/cona)

33.0

* o

d

o

None

(Applied

3.8

Kir

1000 eye

les

)

.. -a .5 - <l) 0) ,1 w

c -'^^ <u O ^ ON ""^

Type of Test Loading

Horiz.

(in-plape)

Shear

Hor

iz

(In

-plane) Shear

Horiz. (In-plane) Shear Horiz. (In-plane Shear

I

Horiz.

(In-plane Shear

Dynam. Wind Load

Horiz.

(In

-p

lane

Shea

r

Dynam.

E.

Quake

Load

Bolt

Pre

-tension

(lb.)

28400 28400 28400 2

8400

28400 o

o

00

Bolt Diam. (in.) tn

Type of Insert n CQ CQ oa ec ca

Grout

Strength at Test \

LJ

(In

joints

and

inset

ts)

56/0 (In

inserts on ly)

6950 w/o

(In

inserts only)

6050 w/o o

Concrete Strength

at Test

(psi)

i

6400 5550 DOH

'J o

oo

A

oo

o

A

Reinf. Design

Fig.

No.

(Crig.

2.

2.1 •H ^

s

Ci -

(Revis

. )

2.

2.6

(Orig.l 2.2. 1

(Grig.)

2.2.1

Test Figure Nos

m CO m <-<

CNl f-* 3.2.3

4.1.18

D. -H U ^ U u o <u

to C

1' c Q OU

Floor toFloor Floor to

Floor Floor toFloor (near corner) Floor to

Floor (near corne

i

)

Floor toFloor Floor to

Floor

Spec

imen

Identification

1

o

M

1 1

O I 2

1 1 +

1 ^

o

2!

1-204-3

Test No. 00 ON o OJ

29
Remarks**

Maximum

load

ruptured

both

studs;

brittle

type

failure;

measured

deformation

was

of

insert

base

plafe

re

concrete.

Maximum

load

ruptured

one

stud;

brittle

type

failure;

measured

deformation

was

df

stud

elongation.

Maximum

load

ruptured

both

studs;

brittle

type

failures;

plate

uplift

and

stud

elongation

measured.

Maximum

load

capacity

was

of

simulating

pulling

apparatus

;meagured

deformation

was

base

plate

avg.

(over

ungrouted

access

block-out)

re

concrete.

Maximum

load

capacity

was

of

simulating

pulling

apparatus;

measured

deformation

was

avg.

of

base

plate

(over

grout-filled

block-out)

re

concrete.

Maximum

load

capac:"--

was

of

simulaiilng

pullii.g

apparatus;

measured

deformation

was

of

base

plate

avg.

(over

grout-filled

block-out"^

re

concreta.

De

forma

it

on

at

Failuie

in

Loading

Direc

tion (

in) 0.

006

0.040 0.

008

(plate

avg.

)

0.046

(studs

avg.

)

0.028 0.

014 0,

031

Failure Load

(kip

/conn)

58.0 (2

bolts) *

55.0 (2

bolts)

57.0 (2

bolts) *

50. 0

(2

bolts)

61.0 (2

bolts)

68.0 (2

bolts)

Type of Test Loading

Tension Tension Tension Tension Tension

Tens

Ion

Bolt

Pre

-tens i

on

(lb.) o

\o

a\ o

vD o

as ovDOS o

a-' o

sD

ON

Bolt Diam. (in) CO o

5/8 (Two) 5/8 (Two) 5/8 (Two: lab. )

J/

O

(Two: lab. )

(Two: lab. )

Type of Insert

Grout

Strength at Test

(psi) w/o w/o w/o w/o (In block-out

J

6890 (In block-out' 7

220

Concrete Strength

at

Test

(psi)

4590 4600 5010 4650 4590 4700

Reinf. Design

Fig.

No. CNl -M

rsi CM CN 2.

2.2

CM

CN

rMCM

Test Figure Nos.

4.2.1 Z.

Z

4.2.3 4.

2.4

60

OO 00 60 O l.r\ so OO 0> r-J CM -NJ CN] CM rsj

<f -d- <f <! <t <^

4.

2.

12

4.

2.13

Descript. of

Connec

tion

Top

of

Wall o ^

4J to Top

of

Wall 0 —

4J CO 2

Top

of

Wall

BOCt.

ot

Wall to Wall

Bott.

of

Wall to Wall

y-C

. Wall to Wall

Spec

imen

Identification

1

1

J

1II-401-2

1

1

III-402-4

1

111-403

-6

1

III-503-6

1

1

III-501-2

1

III-502-4

Test No. <^

1—* in 00 ON

30
5

w

u

njE

QJ CC

Loaded

to

50

kip

max;

total

shear

deformation

at

wall

top

>0.28

Loaded

to

50

kip

max;

total

shear

deformation

at

wall

top3{0.03

in.

Retested

to

42

kip

max;

total

shear

deformation

at

wall

top

>0.13

in.

W.5

in).

Loaded

to

39.4

kip

max;

total

shear

deformation

XI.

08

in.

(5a>1.0

in)

Static

cyclic

loading.

Loaded

to

41.7

kip

max;

total

shear

deformation

>0.12

in.

(Sic.

8

in)

Static

cyclic

loading

Loaded

to

41.2

kip

max;

total

shear

deformation

>0.14

in.

(WO.

5

in).

Loaded

to

44.0

kip

max;

total

shear

deformation

>0.16,

9*0.6

in)

Static

cyclic

loading.

Deformation

at

Failure

in

Loading

Direc

t

ioi,

(In) 0.

007

0.005 0.006 0.

on

0.01

/ 0

. 0

I

0

Fai

lure

Load

;klp

/conn)

30. 0

30. 0

*

CO

25. 0

23. 0 o

1/1

Type of Test Loading

Horiz.

(out-of- plane)

Shear Horiz. (out-of

-

plane)

Shear

Horiz. (out-of

•

plane)

Shear Horiz

.

(out-of

-

plane)

Shear

Horiz.

(out-of

-

plane)

Shear Horiz. (out-of

-

plane)

Shear

Bolt

Pre

-tension

(lb.) 1420 1420 1420 o

CM

1420 o

rsi

DOi

C

Oiam. (in)

<f

ro m cn

<rcn cn

Type of Insert C Q o

Crout

Strength at Test (In

joints

and

A

inserts) 5760 (In

joints

and

A

inserts) 5760 (In

join^s

and

A

inserts) 6830 (In

joints

and

A

inserts) 6830 o o

3

Concrete Strength at

Test

(,psi) 4690 4690 4450 4450 5010 5010

Reinf. DesignFig.

No.

CN

CO

CM

m

CM CM

Test Figure Nos

.

<t ^n

CN CM CM 4.2.

18

4.

2.

19

4.

2.

20

Descript. of

Connec

t

loo

Top

of

Wall to

Floor

Top

of

Wall to

Floor

Top

of

to

Floor

Tod

of

Wall to

Flool

Tup

of

Wall to

Floor p 3| !

looi

Specimen

Identification

1

o

It

CMO

o

M

1

J

1"-

II-001-2

(b)

1

Pf

o

U P.

csl OO

1

II

-002-4

(b)

1 n|

a

O

1

.a

J

1=»|

II-003-6

(b)

1 r 1 1 y f

1 y 1 1 y 1 1 H_ |l 1 M f

Test No. oCN

CM

CM cnCN

31
Table 4.2 Concrete Properties at Time of Placement

Batch

No

Specified

O<^ (-i-ono-f-Vi L. X c: Li^ L. LI (psi)

Slump

(in)

Air

/Ti ^* L* onten t (%)

Unit

Weight

(Ib/ft^)

I 5000 3

not

recorded 142.7

2 4000 2 3.4 145.

1

3 5000 2 3.7 145.5

4 4000 2 2.8 145.5

5 5000 3 lo3 147.8

6 4000 2 1/4 1.5 145.9

7 5000 1 1/2 2.2 149.0

7a 5000 1 1.5 149.5

32
Table 7.1 Sununary of Test Results

Connection

E lement

(Type)

Description

of

Connection

Manner

of

Loading

Minimum

Observed

Load -Capacity,

(kip)

Ductile

Behavior

A floor-to-wall tension 29 „ 5 Yes

B floor-to-floor tens ion 18.0 Yes

B floor-to-floor out-of

plane

shear

14.5 Yes

B floor-to-floor in-plane

shear

10.0 Yes

E 6c F wall-to-wall tension 50.0 InIo

D wall-to-floor out-of - plane

shear

23. 8 Yes

33
List of Figures

Fi gu re 1 .2 .1 Connections in panelized housing system.

F i gu re 1 .2 .2 Type A insert details.

Fi gure 1 .2 .3 Type B insert details.

Fi gu re 1 .2 .4 Type D insert details.

Fi gu re 1 .2 .5 Type E insert details.

F i gu re 1 .2 .6 Type F insert details.

Figure 1 .2 .7 Hardware for Type B insert.

Fi gu re 1 .2 .8 Hardware for Type A insert.

Fi gure 1 .2 .9 Type A insert.

Fi gure 1 .2 .10 Type B insert.

Fi gu re 1 .2 .11 Type D insert (before modification).

Fi gure 1 .2 .12 Type E insert (before modification).

Fi gure 1 .2 .13 Type F insert (before modification).

Fi gu re 1 .2 .14 Floor-to-floor connection (Type B).

Fi gure 1 .2 .15 FI oor- to-wa 1 1 s connection (s kel etal )( Types

A to E to F) . Figure 2 .2 .1 Original design of floor test specimens

(Types A,B) .

Fi gu re 2 .2 .2 Original design of wall-end test specimens

(Types E , F) . Figure 2 .2 .3 Original design of doub 1 e- top- ended

wall test specimens (Type D) .

Fi gure oc

o

. c . 4 Revised design of floor test specimens

(Type A)

.

Fi gu re 2 .2 .5 Revised design of floor test specimens

(Type B) .

Fi gure 2 .2 .6 Revised design of floor test specimens nea

corner (Type B ) .

34
Figure 1.1.1 Removal of block-out over floor insert

connector

.

rFt1 n 1 1 V p ^ u 1 c

Q . o assemb 1 age

.

rP "i1 n 1 1 P y u 1 c %j • ?6. . 1 Tx/nip;^! ij^ui^ai Qtatir oUuLiv^ niill-nii'h pull uu^ tpcil" ucoo ^pt-iin ocu up.

Ft n 1 1 V* p r 1 Lj U 1 c o . c lypiLCll bUClUiL CUIIiprCiilUII LCit ocu up.

Ft n 1 1 V p r 1 u r c

•3 0

. o TN/niral v'Pnp;^'f'pH c;hPfiv" 1'P<;'h ^^pl'-iin

Finn pp 4 1 1 Fynnl" n'f TpcI" 1 flnnr rnnnprtinn plpmpnt

^ (Type A).

F i a ij re 4 1 2 InflH-rli^inlflrpiTipnt aranh for front nf Tp^t 1

Ftr 1 nil f p y u 1 c 4 1 . o Luau uibpictuciiiciit yrapii lui icai ui icot i.

Fi gure 4 .1 .4 Test 2 floor connection element (Type A).

Fi gure 4 .1 .5 Front of Test 3 floor connection element

(Type B)

.

Fi gure 4 .1 .6 Load-displacement graph for front of Test 3.

rFt nil o 1 y u r c 4 1

. 1 7 rrUilL Ui IcbU H- 1 lUUi CUIMIcUtlUrl cltrlllcilL

(Type B)

.

Prn n 1 1 V* o 1 u r c 4 . 1 o

. o rrUilL UI IcbL »J 1 lUUi UUiliicULIUil cIcillcilLb

(Type B)

.

P "i n II y* r 1 y u f c 4 1 0. V LUau~uii>|Jiaut;iiicfiu yrapii lur icit uuiiricL^uiuii

of Tes t 5 .

r 1 gure /I

. 1 1 n . 1 u Kignt connecLion ot lest o Tioor connection

elements (Type B).

Fi gu re 4 .1 .11 Front of Test 7 floor connection elements (Type B ) .

Fi gure 4 .1 .12 Load-displacement graph for right connection

of Test 7.

Figure 4 .1 .13 Test 9 floor connection elements (Type B).

Fi gu re 4 .1 .14 Front of Test 10 floor connection elements

(Type B, near corner).

Fi gure 4 .1 .15 Rear of Test 1 0

.

35
Fi gu re 4 .1 .16 Front of Test 11 floor connection element

(Type B, near corner).

Fi gu re 4 .1 .17 Rear of Tes til.

r 1 g u r e

A

. 1 . 1 O lest \ c Tioor connection elements ^lype b

( af te r test) .

Fi gure 4 .2 .1 Front of Test 14 wall top connection

element (Type E)(before test).

Fi gure 4 .2 .2 Ruptured stud bolts of Test 14.

Fi gure 4 .2 .3 Front of Test 15 wall top connection

el emen t (Type E )

Fi gu re 4 .2 .4 Ruptured left stud bolt of Test 15.

Fi gure 4 .2 .5 Front of Test 16 wall top connection

^iQmQV^'l" I T \t r\ c\ C\ cIciTlcnL \iypc L/,

r 1 gure /It

o

. c. c. D Kupturcu stuu Doits OT lest id.

Fi gure 4 .2 .7 Elongation of right stud bolt in Test 16.

Fi gure 4 .2 .8 Elongation of left stud bolt in Test 16.

r 1 gure 9. L. upi iTt OT Tront eoge ot oase piate in

Test 16.

r 1 g u r c

O

. c 1 n UpiiTl^ OT rear cQyG OT DdSc pidLc in

Test 16.

r 1 gure /I 0. c. . 1 1 lest 1/ wa 1 1 Dottom connection element

(Type F)

r 1 g U r c

/It0

. c . 1 c icst lo Wall Dottom connection eicmcnL

(Type F)

r 1 g u r c

/I 9

. C . i 0 icsu Wail DOLLorn connecLion eiernenL

(Type F) .

r 1 g u re 9

. 1 ^ lests iiu, ci wail top connection elements

(Type D)( before test).

r 1 gure /I 9 lest wail top connection element

(Type D)

Fi gu re 4 .2 .16 Test 22 wall top connection element

(Type D)

Fi gu re 4 .2 .17 Load-displacement graph of Test 22.

36
Figure 4.2.18

Figure 4.2.19

Figure 4.2.20

Test 23 wall top

(Type D) . Test 24 wall top

(Type D) . Test 25 wall top

(Type D).

connection element

connection element

connection element

37


I 3/4"

ELEVATION

1/8" STL CLOSED it - A - 36

WELDED TO TUBE

l"XI 1/2" SLOT

CORNERS ROUNDED

TO 3/8"

EDGE

OF PANEL

6" X 4" X 7/l6"-A-50l

1/2" DIM.X 18" LG. {ASTM. A-496)

DEFORMED ANCHOR BARS

2-1/2" DIA.H.STUD ANCHORS

5" LONG (ASTM A-108)

PLAN cm

Figure 1.2.2 Type A insert details.
1

EDGE

OF PANEL

n

I/I6" ST'L. closer BL - a- 36

(TACK-WELDED TO TUBE)

I 1/4 DIA. HOLE

ELEVATION

3- 1/2 DIA. H STUD ANCHORS

5" LONG- ASTM -A - 108

6" X 4" X 3/8" TUBE ASTM - A- 501

Figure 1.2.3 Type B insert details.

i
ELEVATION

PLAN

1/2"

ir

1/2"

I X2" SLOT WITH 3/8" R. ROUNDED

CORNERS IN 8" X 5

" X 3/4" (A- 441 ) ST'L.

ft. WELD TO 8" X 5 1/2" 3/4" ST'l. IL.

EDGE OF

PANEL

4"-5/8"j^-l8 L6. (ASTM. 496-64)

DEFORMED BAR ANCHOR

3/4". 2 2"^| 3/4" I

-»-- TS" X 5 1/2" X 3/4" STL. A-441

)

Figure 1.2.4 Type D insert details.
EDGE OFPANEL

JL

V4"J

ELEVATION

PLAN

2 -5/8" (}) THREADED STUD (A-325)

WELDED TO STEEL PL

5" X 8" X 3/4" STL PL ( A-441

)

WELDED TO BASE PL

5 1/2 X 2-0 X 3/4

STL BASE PL WITH

ANCHOR BARS (A-441)

6-5/8" ^ - 2 DEFORMED

BARS ANCHORS

(ASTM 496 -64)

Figure 1.2.5 Type E insert details.
if) <

_l CD

Li_ OC 1 oXa

"o <1 X

"(\J i- X

"co

in <

CVJ

CVJ 4-

U.

UJUJ

LlI Ol I

'J-I <

q:oXo

o<

_ I <MI <

(0 iH•H

fd +»

(U -apo

UiG

•iH

0)>^

(UUH

lit <>

UJ

_J

UJ <

_JCL
2 3/4- ELEVATION

13/16 DIA. HOLE

3/8" R.

3/8

2- SPECIAL WASHERS

3" X 2 3/4" X 3/8"- A -36 PLAN

Figure 1.2.7 Hardware for Type B insert.
ELEVATION

PLAN

13/16 DIA. HOLE

•1/2" R.

2- SPECIAL WASHERS

3" X 2 5/8" X 1/2" A -36

SHIMS- A-36

2- 1/4"

4-1/8"

4-1/16"

3/4 DIA. A-325 BOLT X5 LENGTH 8 2- WASHERS 8i NUT

INSERT 'A'- HARDWARE

Figure 1.2.8 Hardware for Type A insert.


(i


Figure 1.2.14 Floor-to-floor connection (Type B)

.

Concrete: 5000 psi @ 28 days

Re. Steel: A-6l5-6rade 60

1

30'

w

° a= l^(Type A)

T a = 1/2" (Type B)

Type B

Type A

ELEVATION

3/4'

Insert Type B

(as needed)

2x7 *3 Mk 301

5"

24

(Cut bars over insert tubes)

Insert Type A or B

2x6 *3 Mk 301

PLAN

Figure 2.2.1 Original design of floor test specimens

(Types A,B)

.
Concrete: 4000 psi @ 28 days

Re. Steel: A- 615- Grade 60

-% Insert Types E 8 F

8 Open - Type F

1

1 «

. 1

30

_ -

ELEVATION

2x7 *3 Mk 302

6 1/2"

40

60

3/4"

b=7/8 Type F b= 1/2" Type E

in

0=6^ Type F

3"

a=2f Type E

END ELEVATION

Inserts Types E SF

PLAN

Figure 2.2.2 Original design of wall-end test specimens

(Types E,F)

.
Concrete: 4000 psi @ 28 days

Re. Steel: A-615 Grade 60

Insert, Type D

both ends

1/2'

7 Mk 303

12"

8-0

«4

30'

2 *5 Mk 501

27"

15'"^

2x2 ^'Sx 7 -9

3 ^4x6-0"

ea. face

4x4-W4x W4

W.W.F ea. face

Both ends

the same

8'^

Mk 501

Mk 303

ELEVATION END ELEVATION

Figure 2.2.3 Original design of double-top-ended

wall test specimens (Type D)

.
Concrete : 5000 psi @ 28 days

Re. Steel: A-615 - Grade 60

Insert -Type A.

Mk. 601

4" ( I 1/4" from bottom)

—V

*

(Cut WW.F over insert

PLAN

Direction of floor span

Figure 2.2.4 Revised design of floor test specimens

(Type A)

.
Concrete; 5000 psi @ 28 days

Re. Steel: A-615-Grade 60

I 1/4'

Insert Type B

ELEVATION

30

Insert Type B

(as needed)

I

!

4- *4 ® a" (I 1/4" from bottom )- 28" eo.

I

4x8 W4xW4

W.W.F Top

3f'

(Cut W.W.F. over insert tube)

o

Q. W

o

o

u

PLAN

Figure 2.2.5 Revised design of floor test specimens

(Type B)

.
ELEVATION

PLAN

Figure 2.2.6 Revised design of floor test specimens near

corner (Type B)

.






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Appendix - Test Results

All test results and other pertinent test data are shown

in table 3.0. Tests are identified by numbers from 1 to 25 and

are correlated with specimen identification numbers and illus- i

trative figure numbers given in the same table. Representative

load-displacement curves (indicated by 'g' in table 3.0) :

are presented for one test in each test group.

The tests illustrated by graphs are those having the minimum observed failure load in each group (except Test 16, chosen

over Test 15 because the additional instrumentation in Test 16

was more informative). The comments which follow expand on particular test procedures and results not fitted into the

Remarks column in table 3.0.

A.l Floor Connections

A. 1.1 Floor Connection Element (Type A) - Tension

TEST 1 - Specimen 1-116-7 was considered to have failed when '

I there was visible and graphical evidence of cracking deformation I developing rapidly at 29.5 kip. No distortion of the rec- .

1 tangular insert tube was apparent even when loaded to maximum

| capacity of 34 kip followed by failure of one anchor bar. The

j LVDT seen in figure 4.1.1 provided data for the graph in ] figure 4.1.2. The graph in figure 4.1.3 was generated by an j

i LVDT similarily mounted on the opposite or rear face of the

i specimen (floor bottom). The difference in the rates of dis-

!

I placement at the two points of observation is attributed to the |

I A-1
greater surface area of tube imbedment (hence, more restraint)

"below" the connection bolt, i.e., to the rear in figure 4.1.1

(fig. 1.2.2 - el evat i on ) .

TEST 2 - Specimen I-lOl-l which contained a grout-filled

insert failed at 38.7 kip in a manner similar to that of Test

1. Damage to grout visible in figure 4.1.4 is a spalled surface

repair and not evidence of internal grout breakdown. Both tail

anchor bars failed at a maximum load of 48 kip. Magnified displacement seen in figure 4.1.4 was produced to examine tail bar

f a i 1 u res .

A. 1.2 Floor connection Element (Type B) - Tension

TEST 3 - Specimen 1-316-7 failed at 18.0 kip when cracking

deformation gave indication of yielding. No distortion of the

insert rectangular tube was observed throughout the test.

Maximum capacity (22 kip) was determined by tensile failure of

tail stud. After-test displacement (in fig. 4.1.5) was increased

by additional pulling to examine stud. Load-displacement curve

in figure 4.1.6 is for front of specimen (top floor surface).

TEST 4 - Specimen 1-301-1 failed at 30.0 kip in a manner

similar to that of Test 3. After-test examination showed that

the crack across the grouted area (fig, 4.1.7) extended only

into the recess of the insert below the walking surface (front)

of the floor specimen; grout in the insert tube was not damaged.

Tail stud tensile failure occurred at a maximum load of 42 kip.

A-2
A. 1.3 Floor Connection Element (Type B) - Vertical (Outof-Plane) Shear

TEST 5 - Specimen 1-208-7 shown in figure 4.1.8 after the

test, failed at 14.5 kip by initial slip of a f ri ct i on- type bolt

connection. The load-displacement curve in figure 4.1.9 is for

the left LVDT (fig. 4.1.8) mounted to measure relative

movement of the two inserts at the left connection. Outer

supporting slabs in the test arrangement were fully restrained

by hydraulic rams (figs. 3.2.2, 4.1.8) to introduce a possible

severe condition of no rotational accommodation of a transversely (out-of-pl ane ) loaded joint.

TEST 6 - Specim'en 1-202- 1 (seen in fig. 4.1.10 after the

test) failed by initial slip at 18.5 kip in the right joint. By

contrast, the supporting slabs in this test were unrestrained

and were permitted to rotate while the center slab was loaded.

A. 1.4 Floor Connection Element (Type B) - Horizontal

(In-Plane) Shear

TEST 7 - Specimen 1-207-7 is shown in figure 4.1.11 after

the test. Spacing of ung routed joints, for this type of test,

was maintained by extra steel shims in the joints at the top of

the assemblage. These shims were oiled and interfaced with

polyethylene film. Failure occurred by initial slip at 10.0

kip in the right connection followed by similar action in the

left one. Continued loading produced increased slip, minor

A-3
detr"sion of bolt-hole edges in the inserts and shear of the

right bolt at 34.5 kip. Figure 4.1.12 is a load-displacement

graph obtained from the right LVDT. Displacement dials placed

at the outer ends of the test assemblage indicated very small

rotational uplift (0.017 in maximum at right end).

TEST 8 - Specimen 1-201-1 is not illustrated. This test

was similar to Test 7 except that the joints and insert tubes

were grout- fi 1 1 ed . Failure occurred by initial slip in one

connection at 33.0 kip. This load was not exceeded during continued deformation. Continued loading produced increased slip,

marked detrusion of bolt hole edges in the inserts and shearing

of one bolt at 33 kip.

TEST 9 - Specimen 1-207-7 (repeat) consisted of the component slabs used in Test 7 (reassembled with unused bolts and

shims) with only the insert tubes grout- fi 1 1 ed . As in Test 7,

ung routed joint spacing was maintained by oiled shims at the

top of the test assemblage. The specimen, after the test, is

shown in figure 4.1.13. Failure occurred by initial slip in

one connection at 11.7 kip followed by similar failure in the

other. Continued loading produced increased slip, marked

detrusion of insert bolt hole edges, apparent bolt bending and

shearing of both bolts at 35.5 kip per bolt.

TEST 10 - Specimen I -209 -7a failed by initial slip of both

connections at 10.0 kip per connection element without any indication of cracking in the concrete. Continued loading proA-4
duced 0.27 in of connection slip and visible cracking at 24 kip

per connection element. Further loading to a maximum load of

33 kip per connection element caused 0.5 in of shear cracking

deformation and racking of insert tubes (figs. 4.1.14, 4.1.15).

TEST 11 - Specimen I-210-7a failed by initial slip of both

connection elements at 11.0 kip per connection element. Progress of 1 oad- def ormat i on was similar to that of Test 10

except for the absence of racking of the grout-filled insert

tubes (which did, however, undergo some rotation under continued

loading) (fig. 4.1.16, right connection). Maximum load produced

the major diagonal crack at the right connection; shear failure

of the bolt followed. The back of the specimen is shown in

f 1 gure 4 . 1 . 1 7 .

TEST 12 - Specimen 1-205-5 was subjected to simulated

repeated wind loading causing an in-plane shear force of 3,8

kip per connection element (figs. 3.2.3, 4.1.18). Load was

varied (as a haversine function) from 0 to 3.8 kip per connection element for 1000 cycles at a frequency of 0.1 Hz. The

oscillograph record of the entire test showed no detectable

slip in either connection within the limit of resolution

(0.00 5 in) .

TEST 13 - Specimen 1-204-3 was subjected to a repeated

in-plane shear force of 6.9 kip per connection element. The

load was a sine function between the limits of + 6.9 kip per

connection element for 5 cycles at a frequency of 0.1 Hz. The

A-5
experimental setup is illustrated by the same figures used to

illustrate Test 12. The oscillograph record of the entire test

showed no detectable slip in either connection within the limit

of resolution (0.005 in).

A. 2 Wall Connections

A. 2.1 Wall-Connection Element (Type E) - Tension

TEST 14 - Specimen III-401-2 failed when a maximum total

load of 58.0 kip caused tensile rupture of both stud bolts.

Relative movement between the insert horizontal base plate and

undisturbed concrete was measured by the LVDT shown in figure

4.2.1, as well as by an LVDT mounted on the rear face of the

specimen. The base plate uplift of 0.006 in given in table 3.0

is the greater value of the two sides instrumented (front).

Tensile failures of the stud bolts were observed not to have

experienced any readily apparent reduction in cross section,

i.e., necking down (fig. 4.2.2).

TEST 15 - Specimen III-402-4 failed at a maximum total

load of 55.0 kip at which time one stud bolt was ruptured in

tension. Average maximum elongation in the studs (in a 2-7/8

in length under tension) was 0.04 in. Maximum elongation in th

ruptured stud was 0.09 in; yielding of the ruptured stud permitted the pulling device to rotate and allowed the second stud

to recover. Elongation of the studs was measured by LVDT's (fi

A-6
4.2.3) with reference to the vertical tongue plate of the

insert and under-surface of the stud nuts (fig. 4.2.4).

TEST 16 - Specimen III-403-6 failed by tensile rupture of

both stud bolts at a total maximum load of 57.5 kip. As shown

in figure 4.2.5, this specimen was instrumented to measure

approximate elongation of the studs on the right and left

sides of the insert tongue plate, as well as uplift displacement of the insert base plate with respect to the front and

rear faces of the concrete specimen. The extra LVDT at the

right side of the tongue was used for test monitoring. The

specimen after the test is shown in figure 4.2.6. At failure,

the average elongation in 2 7/8 in of the individual studs (figs

4.2.7, 4.2.8) was 0.046 in; some recovery occurred in the left

stud. The average uplift of the two edges of the base plate

(figs. 4.2.9, 4.2.10) was 0.008 in at failure.

A. 2. 2 Wall Connection Element (Type F) - Tension

TEST 17 - Specimen III-503-6 and similar ones were tested

upside down. Each test of this type was terminated by failure

of the pulling apparatus (5/8 in A-325 nuts and bolts which simu

lated the stud bolts of a mating Type E insert in practice).

The total maximum load of 50.0 kip stripped the threads of

both "nuts. Insert plate uplift was measured at the front and

rear faces as in preceding tension Tests 14 and 16. Figure

4.2.11 shows the stripped nuts and minor (penciled) cracks in

A-7
the roncrete specimen near the ungrouted access block-out. The

cracks were observed at 40 kip.

TEST 18 - Specimen III- 50 1-2 sustained a total maximum

load of 61.0 kip. Failure was by thread stripping of one pulling bolt nut (fig. 4.2.12). An audible sound of slip was heard

at a 10-kip total load although there was not visible indication

of distress. At 38 kip, a vertical hairline crack was observed

at the front centerline of the grout fill. At failure, this

crack closed and was not visible. Figure 4.2.12 also shows how

a reference fixture for the LVDT core was attached to the edge

of the insert plate in a grouted specimen at the front and rear.

TEST 19 - Specimen III-502-4 sustained a total maximum

load of 68.0 kip. The test was ended by rupture of both pulling

bolts. Plate uplift was measured at front and rear. Figure

4.2.13 shows (penciled) cracks in the concrete after the test.

A. 2. 3 Wall Connection Element (Type D) - Horizontal (Out-ofPl ane ) Shear

The assemblage used in each of these tests provided a symmetrical double specimen. Each half of an H-assemblage

(a and b, in fig. 4.2.14) simulated a T-connection of two floor

slabs connected to a bearing wall top (inserts A to D to A).

The position for testing was rotated 90° from that in actual

use. Thus, an artificially doub 1 e- top-ended test wall panel

(fig. 2.2.3; horizontal in fig. 4.2.14) contained a Type D insert at both ends, a and b. In order to subject the Type D A-8
connection elements to direct out-of-plane shear, i.e., with

the floor panels restrained from rotating, steel struts (I-beams)

were grouted between the two upper floor panels. Threaded steel

tie rods with cross channels were grouted around the two lower

panels for the same purpose (fig. 4.2.14). Except for Test 20,

subsequently described, each test in this group was one-half

of an H-assemblage loaded independently. Observed ram load

values were converted to a parallel total equivalent load

acting at the "top" edge of the wall panel, i.e., an insert

reaction considered to act at the junction of the insert base

plate and tongue (figs. 1.2.11, 2.2.3). Out-of-plane (transverse) shear failure was considered to have occurred in tests

of this group when there was visible shear cracking around the

Type D insert and an increased rate of deformation as observed

on the load-deflection monitor.

TEST 20 - Specimen II-001-2(a) was for one of two assemblage halves loaded simultaneously. Transverse shear failure

occurred at 30.0 kip. The specimen was loaded to a maximum

load of 50 kip with a corresponding deformation in excess of

0.28 in. Transverse shear deformation was measured between the

wall panel side areas and its central area over the imbedded

insert (end b of fig. 4.2.14). Figure 4.2.15 shows the transverse shear failure after testing with the test apparatus re- moved. Areas to either side of the cracked portion are covered

with plate embedment plaster.

A-9
T EST 21 - Specimen II-001-2(b) was tested simultaneously

with the preceding one as shown in figure 4.2.14. Failure

occurred by shear, similar to Test 20. The two rams used for

testing the whole assemblage were operated by a common pump.

End (a) yielded more readily than (b). Thus, the deformation

at end (b) lagged the maximum load (0.03 in at 50 kip). End

(b) was, therefore, retested independently. In the retest a maximum load of 42 kip was reached at 0.13 in deformation after

which the continued loading dropped off to 36 kip at a deformation of 0.46 in. Loading apparatus and instrumentation mounts

for the retest (and following tests) were slightly altered to

reduce the confinement of the concrete around the Type D insert.

Modified loading hardware appears in photos of subsequent tests.

TEST 22 - Specimen II-002-4(a) was tested by static cyclic

loading. Each load application was increased by an increment

of 4 kip. Apparatus and specimen after testing are shown in

figure 4.2.16. Note the smaller, less confining pressure plates

and the mounting of the LVDT directly on the wall panel side

edges. Transverse shear failure occurred at a load of 23.8 kip.

The highest loading cycle reached a maximum of 39.4 kip at 0.08

in deformation, beyond which loading was continued without cycling.

A transverse deformation of about 1 in was reached at a diminishing load of 27 kip. Figure 4.2.17 shows the computer plot

of load-displacement relationship at the ends of each cycle.

Data were recorded at zero loads and at each new load increment.

A-10
Lines between plotted points were added to indicate cyclic

sequence and do not represent the exact path between points.

TEST 23 - Specimen II-002-4(b) was also tested by cyclic

loading similar to that of the preceding test. The apparatus

and specimen after the test are shown in figure 4.2.18. Transverse shear failure occurred at a load of 25.0 kip. The last

loading cycle reached a maximum of 41.7 kip at 0.12 in deformation, beyond which loading was continued without cycling. A

transverse deformation of about 0.8 in was reached at a diminishing load of 27 kip. An additional displacement measuring

dial was used in this test to observe movement of the wall

panel in the vicinity of the insert with respect to the attached (upper) floor panel. A maximum movement of the wall of 0.02

in in the direction of the applied force was observed at maximum load.

TEST 24 - Specimen II-003-6(a) failed by shear at a load

of 25.0 kip. Loading was by 4 kip increments without cycling.

Continued loading reached a maximum of 41.2 kip at a shear

deformation of 0.14 in. Further loading dropped to 29 kip at

a deformation of about 0.4 in. Dia 1 -meas ured displacement of

the wall panel relative to upper fl.oor panel near the Type D

insert was 0.06 in at maximum load. Figure 4.2,19 shows the

specimen cleared of concrete debris after the test. Also

visible is the large joint (1-3/4 in) between floor panel

edges which was in all test assemblages of this group. The

A-11
joint width was created by two 1/4-in shims on both sides of

the Type D insert tongue to prevent interference of fillet

welds (which join tongue to base plate, fig. 1.2,11) with the

bearing edge of floor panels.

TEST 25 - Specimen II-002-6(b) was tested by static cycli

loading similar to that of Tests 22 and 23. Failure by shear

occurred at a load of 25.0 kip. After failure, loading was

continued, without cycling, to a maximum of 44 kip at a shear deformation of 0.17 in. Loading beyond the maximum was

continued to a diminishing load of 40 kip at a deformation of

about 0.28 in. Excessive fragmenting of the concrete near the

LVDT core prevented further deformation readings. However,

figure 4.2.20 shows evidence of additional deformation (0.6 in

caused by further drop-off loading. '

A-1 2
FORM NBS-IHA (1-71)

. ,l.'.o. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. 2. Gov't Accession

No. NBSIR 73-126

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Structural Tests

Panels

of Mechanical Connections for Concrete

5. Publication Date

6. Performing Organization Code

7. AUTHOR(S)

Louis E. Cattaneo and Felix Y. Yokel

8. Performing Organization

NBSIR 73-126

9. PERFORMING ORGANIZATION NAME AND ADDRESS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4600432

11. Contract/Grant No. IAA-H-16-70

12, Sponsoring Organization Name and Address

Office of Research and Technology

Department of Housing and Urban Development

Washington, D.C. 20410

13. Type of Report & Period

Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

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

bibliography or literature survey, mention it here.)

Structural evaluation tests were performed on prototype steel insert connectors

proposed for joining floor and wall panels of a precast concrete housing system

included in Operation BREAKTHROUGH. Descriptions are given of 25 tests conducted

with 5 different types of connectors. Specimen connections were laboratory

tested under simulated design loading conditions to evaluate their load capacity

and ductility.

17. KEY WORDS (Alphabetical order, separated by semicolons) Concrete panels; connections; ductility;

floor diaphragms; housing systems; insert connectors; Operation BREAKTHROUGH;

18. AVAILABILITY STATEMENT 19, SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

Pn UNLIMITED.

UNCL ASSIFIED

1 1 FOR OFFIQAL DISTRIBUTION. DO NOT RELEASE

TO NTIS.

20, SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

22. Price

ii11I