The program of research on building materials and structures, carried on by the

National Bureau of Standards, was undertaken with the assistance of the Central

Housing Committee, an informal organization of governmental agencies concerned

with housing construction and finance, which is cooperating in the investigations through

a subcommittee of principal technical assistants.

CENTRAL HOUSING COMMITTEE

SUBCOMMITTEE ON TECHNICAL EESEARCH

Walter Junge, Chairman. A. C. Shire, Vice Chairman.

Federal Housing Administration. United States Housing Authority.

Sterling R. March, Secretary.

Albert G. Bear, George E. Knox,

Veterans' Administration. Yards and Docks (Navy).

Pierre Blouke,

Federal Home Loan Bank Board Vincent B. Phelan,

(Federal Loan Agency). National Bureau of Standards (ComCarroll W. Chamberlain, merce).

Public Buildings Administration (Fed- ^

eral Works Agency). Edward A. Poynton,

Joseph M. DallaValle, Office of Indian Affairs (Interior).

Public Health Service (Federal Security George W. Trayer,

Agency). Forest Service (Agriculture).

John Donovan,

Farm Security Administration (Agri- Elsmere J. Walters,

culture). Construction Division (War).

CHAIRMEN OF SECTIONS

Specifications Materials Maintenance

Carroll W. Chamberlain Elsemere J. Walters John H. Schaefer

Mechanical Equipment Methods and Practices

Robekt K. Thulman

NATIONAL BUREAU OF STANDARDS

STAFF COMMITTEE ON ADMINISTRATION AND COORDINATION

Hugh L. Dryden, Chairman

Mechanics and Sound

Phaon H. Bates, Gustav E. F. Lundell,

Clay and Silicate Products. Chemistry.

Hobart C. Dickinson, Addams S. McAllister,

Heat and Power. Codes and Specifications.

Warren E. Emley, Henry S. Rawdon,

Organic and Fibrous Materials. Metallurgy.

The Forest Products Laboratory of the United States Department of Agriculture

is cooperating with both committees on investigations of wood constructions.

[For list of BMS publications, and how to purchase, see cover page III.]
UNITED STATES DEPARTMENT OF COMMERCE • Harry L. Hopkins, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS40

Structural Properties oi a Wall Construction

of "Knap Concrete Wall Units"

Sponsored by Knap America Inc.

by HERBERT L. WHITTEMORE, AMBROSE H. STANG,

and CYRUS c. fishburn

ISSUED FEBRUARY 21, 19 40

The National Bureau of Standards is a tact-finding organization;

it does not "approve" any particular material or method ot construction. The technical findings in this series ot reports are to be construed accordingly.

UNITED

FOR SALE

STATES GOVERNMENT PRINTING OFFICE • WASHINGTON •

BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE lO

1940

CENTS
Foreword

This report is one of a series issued by the National Bureau of Standards on the

structural properties of constructions intended for low-cost houses and apartments.

These constructions were sponsored by industrial organizations within the building

industry advocating and promoting their use. The sponsor built and submitted the

specimens described in this report for participation in the program outlined in BMS2,

Methods of Determining the Structural Properties of Low-Cost House Constructions.

The sponsor, therefore, is responsible for the design of the constructions and for the

description of the materials and method of fabrication. The Bureau is responsible for the method of testing and the test results. This report covers only the load-deformation relations and strength of the walls of a house when subjected to compressive, transverse, impact, concentrated, and racking

loads by standardized methods simulating the loads to which the walls would be subjected in actual service. Later it may be feasible to determine the heat transmission

at ordinary temperatures and the fire resistance of this same construction.

The National Bureau of Standards does not "approve" a construction, nor does it express an opinion as to the merits of a construction for the reasons given in reports

BMSl and BMS2. The technical facts presented in this series provide the basic data

from which architects and engineers can determine whether a construction meets desired

performance requirements.

Lyman J. Briggs, Director.

[ii]
Structural Properties of a Wall Construction of "Knap Concrete

Wall Units" Sponsored by Knap America Inc.

by HERBERT L. W H ITT E MO R E, AMBROSE H. STANG,

illlil CYRUS C. FISH BURN

CO NTE NTS

Page

Foreword ii

I. Introduction 1 II. Sponsor and product 2

III. Specimens and tests 2

IV. Wall BW : 2

1. Sponsor's statement 2

(a) Materials 2

(b) Description 5

(1) Four-foot wall specimens. - 5

(2) Eight-foot wall specimens. fi

ABSTRACT

For the program on the determination of the struc- tural properties of low-cost house constructions,

Knap America Inc. submitted 12 specimens representing a wall construction of "Knap Concrete Wall

Units." The specimens were subjected to compressive,

i transverse, concentrated, impact, and racking loads. For each of these loads three like specimens were tested. The deformation under load and the set after the load was removed were measured for uniform increments

of load, except for concentrated loads, for which the

set only was determined. The results are presented in graphs and in tables.

I. INTRODUCTION

In order to provide technical facts on the

performance of constructions which might be

used in low-cost houses, to discover promising new constructions, and ultimately to determine the properties necessary for acceptable

performance in actual service, the National

Bureau of Standards has invited the cooperation of the building industry in a program of research on building materials and structures

I suitable for low-cost houses and apartments.

The objectives of this program are described

in report BMSl, Research on Building Materials and Structures for Use in Low-Cost

Housing, and that part of the program relating

198877°~4n

Page IV. Wall BIT—Contiiuied.

1. Sponsor's statement—Contiiuiod.

(c) Comments 7

2. Compressive load 9

3. Transverse load 11

4. Impact load 12

5. Concentrated load 13

6. Racking load 13

to structural properties in report BMS2,

Methods of Determining the Structural Properties of Low-Cost House Constructions.

Masonry constructions and wood constructions of types which have been extensively

used in this country for houses were included

in the program because their behavior under

widely different service conditions is loiown to builders and the public. The reports on these

constructions are BMS5, Structural Properties of Six Masonry Wall Constructions, and

BMS25, Structural Properties of Conventional

Wood-Frame Constructions for Walls, Partitions, Floors, and Roofs. The masonry speci- mens were built by the Masonry Construction

Section of this Bureau, and the wood-frame

specimens were built and tested by the Forest

Products Laboratory at Madison, Wis.

The present report describes the structural

properties of a wall construction sponsored by

one of the manufactiu'ers in the building

industry. The specimens were subjected to compressive, transverse, concentrated, impact,

and racking loads, simulating loads to which

the walls of a house are subjected. In actual

service, compressive loads on a wall are pro- duced by the weight of the roof, second floor and second-story walls if 9ny, furniture and

occupants, and snow and wind loads on the

1
roof. Transverse loads on a wall are produced

by the wind, concentrated and impact loads by

accidental contact with heavy objects, and

racking loads by the action of the wind on

adjoining walls. The deformation and set under each increment of load were measured, because, considered as a structure, the suitability of a construction depends not only on its resistance to deformation when loads are applied, but also on whether it returns to its original size a,Tid shape when the load is removed.

[I. SPONSOR AND PRODUCT

The specimens were submitted by Knap

America Inc., Los Angeles, Calif., and repre- sented a patented cavity-wall construction of reinforced-concrete units marketed under the

trade name "Knap Concrete Wall Units."

Vertical joints in the wall contained wood

splines pinned to the units.

III. SPECIMENS AND TESTS

The wall construction was assigned the symbol BW, and the specimens were assigned the

designations given in table 1.

Table 1.Specimen designation.-i, 7vnU BW

Spooimon

dosignation I>iiad applied

CI. C2, CS

77, n, TS

7/, 72, TS PI, pa, PS * 7?;, 7^2, m

Compressive ... Transverse.. . . Impact . Coneenfrated RaoVin;Upper end. Either face. Do.

"Po. Near upper enc).

» These specimens were undamaged portions of the impact specimens. With the exceptions mentioned below, the

specimens were tested in accordance with

BMS2, Methods of Determining the Stnictural Properties of Low-Cost House Constructions, which also gives the requirements for the specimens and describes the presentation

of the results of the tests, particidarly the loaddeformation graphs.

For the transverse, concentrated, and impact

loads, the loads were applied to only one face,

because the results for loads so applied should

be the same as those obtained by applying the

loads to the other face. The compressive loads were applied over the

entire thickness of each specimen along a line

distant from the "inside" face by one-third this thickness. The shortenings and sets were measured by means of compressometers attached to the steel loading plates through which the load was applied to the specimen, not attached to the specimen as described in BMS2.

The deformations due to racking loads were measured with a dial micrometer, which was

fastened to one end of a right-angle frame, consisting of a steel channel and a steel angle

braced to form a rigid connection. In use, this deformeter was attached to the specimen by

resting the channel along the top of the speci- men. Two pins driven through the channel into

the top of the specimen prevented relative motion between them. The steel angle was then

in a suspended vertical position in the plane of

the specimen, with the micrometer at its lowest

point and the spindle bearing directly on the

specimen. The gage length (distance from the

top of the specimen to the micrometer spindle) was 6 ft. 6 in. The micrometer was graduated

to 0.001 in. and readings were recorded to the nearest division. This deformeter was used in- stead of the system of taut wires and mirror

scales described in BMS2.

The tests were begun December 19, 1938 and

completed December 23, 1938. The sponsor's

representatives witnessed the tests.

IV. WALL BW

1. Sponsor's Statement

The information on materials and fabrication of the units was obtained from the sponsor

and from inspection of the specimens.

The Masonry Construction Section of this

Bureau assisted by determining the physical

properties of the mortar and the units. The

species of the wood splines was determined by

the Forest Products Laboratory.

(a) Materials

Concrete v,nit.s. —The materials for the concrete were Monolith Portland Cement Co.'s "Monolith" portland cement, pit sand, fine gravel, and coarse gravel from the vicinity of Los Angeles. The cement complied with the

specifications of the ASTM Standard C9-30 ^

1 Am. Soc. Testing Materials, Book of ASTM Standards, pt. 2 (1936)

[2]
for Portland Cement. The sand contained

1 percent of silt antl the gravels a trace of silt, as determined by the ASTM Standard D136-

28; ^ Method of Decantation Test for Sand and

Other Fine Aggregates. The specific gravity

of the sand was 2.65 and of the gravels 2. 64. The sieve analyses of the sand and gravels are given in table 2. Table 2.

Sieve analyses of the sand and gravels for the concrete units, wall BW

Sieve Passing, by weight

Size u. s. standard No. Sand Fine

gravel Coarse

travel

Inches Percent Percent Percent

10069

113

1

100

34

68

1630

50 100

200

100 58

98

84SO

17

4

1

6

1

The units were thin reinforced-concrete slabs

about 1 ft 9 in. high by 3 ft 4 in. wide. There

were parallel ribs on one face at midwidth and

adjacent to each lateral (vertical) edge.

The reinforcement in the units was a special

mesh made from cold-drawn, basic steel wire,

uncoated. No. 12 Stl. W. G. (0.1055-in. diam),

having a tensile strength of 92,800 Ib/in^. The

wire was woven into a mesh and lap-welded.

Manufactured by the E. F. Krause Wire

Corporation.

The inner surface of the units was covered

with a moisture-resistant paper built up of two

sheets of kraft paper combined (duplexed) by

asphalt. The weight of the paper was 65.5

lb/ream, or 11.3 lb/500 ft^, and the weiglit of the asphalt was 54.5 lb/ream, or 9.4 lb/500 ft^. Manufactured by the Angler Corporation.

The units were formed in horizontal molds

of cast aluminum with the inner surface down.

The mold was lined with the moisture-resistant

paper. The mesh reinforcement was }{, in. above the bottom of the mold, and the edges of the mesh were turned down into the ribs. The

concrete mix was 1 part of cement, 2.11 parts

of dry sand, 1.40 parts of dry fine gravel, and

1.64 parts of dry coarse gravel, by weight, and

' See footnote 1.

the water-cement ratio was 3.94 gallons per sack of cement. The niohl was filled with

concrete and vibrated for nboiit 1 minute.

The upper surface of the unit was finished with

a layer of cement and sand, and then sand

floated. After removal from tlie mold the unit was steam-cured at 125° F for about 4 hours,

after which it was kept moist for 28 days.

The compressive strength of tlie concrete,

determined on 3- by 6-in. cylinders, vibrated,

steam-cured, and kept moist in the sanu; manner as the units, was 2,900 lb/in. ^, age 7 days, and 4,650 lb/in. ^ age 28 days.

Four sizes of units are shown in figure 1

; details of standiird unit, A, and half-height

unit, B, are shown in figure 2; with half-height

unit, C, and quarter unit, D, shown in figure 3. The size of the pieces of the mesh reinforcement

for the standard unit, A, was 1 ft S% in. by 3 ft 6% in. The mesh for the other units was cut from like pieces. All units were made in the same mold by the

use of removable metal stops. There was a semicircular groove, K-in. diam, along each

edge of the standard unit. The lip of the

grooves on the inner surface projected }i in. beyond the lip on the outer surface. The

edges of the other units were grooved except

those edges in contact with a stop in the mokl.

There were holes having a diam of K in. through

the ribs of the units, 1 in. from the edge of

the ribs. The physical properties of two

standard units were determined. The absorption for 24-hr cold total immersion was 4.6 percent of the dry weight of the unit, or 6.4 lb of water per cubic foot of concrete. The

average weight was 142 lb/ft ^ of dry concrete. The dry weight of a standard unit was 95.6 lb, of a half-height unit 45.6 lb, of a half-width

unit 46.9 lb, and of a quarter unit 23.7 lb. Cement mortar.—The cement mortar was 1 part of North American Cement Co.'s "North

American" portland cement to 3 parts of damp

Potomac River building sand, by volume.

This corresponds to 1 part of cement to 2.5 parts of dry sand, by weight, assuming that

Portland cement weighs 94 Ib/ft^ and that

80 lb of dry sand is equivalent to 1 ft" of loose

damp sand. The mortar was mixed in small

quantities by the mason to the consistency

desired.

[3]
Two samples were taken from each batch of mortar, the flow cletermhied in accordance with

Federal Specification SS-C-181b, Cement; Masonry, and six 2-in. cubes made. Three cubes were stored in water at 70° F and three stored

in air near each specimen. The physical

properties of the mortar are given in table 3.

Table 3.

Physical properties of cement mortar, wall BW

Compressive Age strength Batch Specimens Flow when

tested Air Water

storage storage

Percent Days Ih/in.''

1 CZ, CS, Tl, T2, T3, IS »> 150 7 1.070 720

2 CI, 11, IZ, Rl, m. R3 »> 150 5 1, 000 son

Symtiol (>) means "greater than."

"Brixtnent" moriar.—The materials for the

"Brixment" mortar were LouisA ille Cement

Co.'s "Brixment" cement and Potomac River

building sand. The mix of the mortar was 1 part of "Brixment" cement to 3 parts of sand,

by volume.

Wood splines.—Longleaf southern pine, merchantable grade, identified by the Forest Products Laboratory as southern yellow pine.

Typical splines are shown in figure 4. The minimum moisture content of the wood

in the splines was 11 percent, the maximum 25

percent, and the average 17 percent. The

moisture content was determined with an electrical moisture meter on the day the wall specimen was tested. To calibrate the meter, one sample of the wood was taken from each specimen and dried in an oven at 212° F until the

weight was constant. The moisture content was the difi'erence between the initial weight

and the weight when dry, divided by the weight

when dry. The average meter reading for these saniples was 1.0 less than this moisture

content, and therefore the moisture content of

-1
Figure 2.

Details of concrete units. A, standard unit; B, half-height unit.

the wood was obtained by adding 1.0 to the

meter readings and then rounding the result to the nearest whole number.

Pins.—Steel-wire spikes, special, Ke-in. diam,

7}^ in. long, flat head, diamond point. American

Steel & Wire Co.

Bolts.—Machine, mild-steel, Ke-hi. diam, 5 in. long, 14 tlireads per inch, threaded for a length

of 1 % in., heads and nuts square, unfinished.

Washers.—Sheet-steel, l^-in. diam. No. 15

U. S. Std. Gage (0.069 in. thick).

{h) Description

Wall BW was a masonry cavity wall consisting of "Knap Concrete Wall Units" and wood

splines. The units and the splines were con- nected by pins.

The price of this construction in Washington,

D. C, as of July 1937, was $0.39/ft^

Figure 3.Details of concrete u7iits.

C, half-width unit; D, quarter unit.

(1) Four-foot wall specimens.—The 4-ft wall

specimens, shown in figure 5, were 8 ft 1% in. high, 5 ft 0 in. wide, and 5 in. thick. There

were four courses consisting of standard units,

A, and half-width units, C, and one course of half-height units, B, and a quarter unit, D, with

a continuous vertical joint in each face of the

specimen. Each horizontal joint was at midheight of the opposite full-height units in the

other face of the specimen. Each vertical

joint was at midwidth of the opposite full- width units in the other face of the specimen.

The top course of one face consisted of one

half-height unit, B, and one quarter unit, D,

and the bottom course of the other face consisted of two like units. There was a verticnl row of half-width units in each face of the wall,

and the vertical joint in one face was 1 ft 8 in. from the vertical joint in the other face. A

[5]
Figure 4.—Typical

wood splines.

wood spline, E, 2% in. wide, Ifs in. thick at one

edge, and beveled on both sides to a thickness

of 1% in. at the other edge, 8 ft 1% in. long, was

pinned to the ribs of the units at the vertical

joints; the pins passing through the holes in

the ribs and through }^in. holes spaced 10% in. on centers in the splines. A half spline, F,

2% in. wide, % in. thick at one edge, and beveled on one side to a thickness of % in. at the other

edge, 8 ft 1% in. long, was at each edge of the

specimen and was fastened to the ribs of the

units by bolts passing through the holes in the

ribs and through }2-in. holes spaced 10% in. on

centers in the half splines. There was a washer under the nut on each bolt. The pinned

and bolted connections are shown in figure 6. Each joint in the specimens was calked with

cement mortar, then raked to a depth of Yi in. The specimens included in batch 2 (see table 3)

were pointed with "Brixment" mortar. The

joints in the specimens in batch 1 were raked

but not pointed. A pointed joint is shown in

hgure 7. As the only purpose of the mortars was to make the joints weatherproof, not to increase

the strength, the specimens were not aged for 28 days before testing. The age ranged from

2 to 7 days after the joints were calked.

(2) Eight-foot wall specimens.—The 8-ft wall

specimens shown in figure 8 were 8 ft 1% in. high, 8 ft. 4 in. wide, and 5 in. thick. The

specimens were similar to the 4-ft specimens

and consisted of two standard units. A, and a

half-width unit, G, in each course. The top

course of one face and the bottom course of

the other face consisted of two half-height units,

B, and a quarter unit, D. There were four

splines, E, at the vertical joints between the

1
Figure 5.

Four-foot wall sipecimen BW.

A, standard unit; B, half-height unit; C, halt-width unit; D, quarter unit; E, spline; half spline.

units, and two luilf s|)liiic,s, F, at tin; cdg(!s of the specimen.

(c) Comments

"Knap Concrete Wall Units" were originally

developed in South Africa, where during the

past 9 years several hundred structures have

been built of this type of unit. The units

described in this report were an improved design

developed in the United States. Walls and partitions are erected on either a masonry foundation wall or a concrete slab.

If there is a wood floor, the joists are supported

by the foundation walls. Walls are anchored by

steel bars embedded in the foundation and projecting into the cavity of the wall. After two

courses of units have been placed, the cavity is filled with grout to a depth of 5 in., embedding

Figure 6.

Fastening concrete units to wood splines.

a, pin through ribs and spline at inner ribs; h, bolt through ribs and half spline at edge ribs.

[7]

the ends of the bars. Special interlocking

units are made for the corners. Partitions of

similar units or other material are secured to the walls by bolts or other devices. The imits

are made in various sizes to provide flexibility in design and room dimensions, the minimum

width being 1 ft 3 in. Larger units in increments of 5 in. are provided for dift'erent lengths

of walls between openings. The height of the

wall may be varied in increments of 10% in. Lintels over doors and windows are not necessary. Wood door and window frames are

nailed to the wood splines. For metal windows

the splines are omitted and the frames fitted into the recesses between the units. Wood top

plates are fastened to the wall by hook bolts

which engage the upper pin holes in the splines

and in the ribs of the topmost units. Special

units are available for gable ends, or the gable

may be constructed of other materials.

The units are not bedded in mortar when they

are placed. Both the vertical and the horizontal joints are calked after the walls and roof

are erected.

For two-story buildings, special units having

openings are placed in the inside face at the

second-story floor line, and a continuous wood

b(^a,ring plate is nailed to the wood K[)Iines.

The ends of the floor joists extend into the wall

4 in. and are secured by steel plates, 8 by 8 by

% in., either screwed or nailed to the sides of the joists and fastened to the wall by bolts through the pin holes in the units. A rein- forced-concrete floor is anchored by extending

the concrete reinforcement of the floor into the

wall cavities and embedding the bent ends of the bars in concrete. Several lightweight aggregates have been

used to decrease the weight of the units. The faces of the wall recjuire no finishes, but,

if desired, plaster, paint, or wallpaper may be

applied. At no place is the concrete continuous

through the wall. Pipes and conduits are put

in the cavities in the wall. Larger ducts, such

as soil pipe, are located between double walls. The method of fastening the units allows

the house to be dismantled easily ; therefore, the

salvage value of the material is high.

2. Compressive Load

Wall specimen BW~G1 under compressive

load is shown in figure 9. The results for spec- imens BW Cl, C2, and C3 are shown in table 4 and in figures 10 and f 1.

Table 4.Structural properties, wall BW

[Weight, 32.3 lh/ft2]

Compressive load " Transverse load * Impact load ' Concentrated load Racking load

Specimen

Maxi- mum

load Specimen

Maxi- mum

load Specimen

Maxi- mum

height of drop

Specimen

Maxi- mum

load Specimen

Maxi- mum

load

CI... __. 'Kips/ft20.

1

24. 4 19.8

Tl

Ih/P204 220

192

11

ft

1 10.0

J 10.0

<< 10.0

PI

lb

i

1, 000

<< 1, 000

•• 1, 000

Rl

'Kip.slft

4. 14

4. 20

4. 72 C2 12 P2

CS T3 IS PS R3

Average.- _ 21. 4 Average 205 Average J 10.0 Average 1, 000 Average _ 4. 3.5

° Load applied 1.67 in. (one-third the thickness of the specimen) from one face.

' Span 7 ft 6 in.

' A kip is 1,000 lb. Test discontinued. Specimen did not fail. The shortenings and sets shown in figure 10

for a height of 8 ft were computed from the

values obtained from the compressometer

readings. The gage length of the compressometers was 8 ft 2 in. The lateral deflections shown in figure 1 1 were

plotted to the right of the vertical axis for deflections of the specimens toward the "outside" face (positive deflection) and to the left

for deflections toward tlie "inside" face (negative deflection).

For specimens 01 and CS the deflections and

sets were positive. For specimen C2 they were

very small, sometimes positive, sometimes

negative, under loads less than about 23 kips/ft.

Under greater loads the deflections were positive and increased markedly with little change

in the load.

[9]
20

I<<> 4

- —

r-0-|

-©——

— — —GH C

«

—o ( 3 —

L

—•<

/

-«»

1/

1 —

•

I1/•

/V

OM 0.08 0.1? shorfen/nc/ in./Sff

Figure 10.

Compressive load on wall BW.

Load-shortening (open circles) and load-set (solid circles) results for specimens BM'-Cl, C2, and CS. The load was applied 1.67 in. (one- third the thickness) from the inside face. The loads are in kips per

foot of actual width of specimen.

CD 20

Figure 9. — Wall specimen BW-Cl under compressive

load. 1

8

4

-J> 1 1

1

2d

if

IT

-0.? 0 0.2 OA

laferal deflech'on in. Figure 11.

Coinpi-essive load on wall BW.

Load-lateral deflection (open circles) and load-lateral set (solid circles) results for specimens BW-Cl, C2, and CS. The load was applied 1.67

in. (one-third the thickness) from the inside face. The deflections and

sets are for a gage length of 7 ft 11 in., the gage length of the deflectometers.

[10]
i

1

•I

-I

Figure 12. —Wall s-pecinien BW-T2 under tranfiverse load.

In each of the specimens the mortnr crushed

in most of the horizontal joints. The crushing

began at a load of 14.0 kips/ft on specimen Gl,

19.2 kips/ft on specimen 02, and 14.0 kips/ft on specimen 03. Under the maximum load

each of the specimens failed by crushing of the

horizontal mortar joints and of the concrete

units; Mic hilci'iil dcflccl ion I'lingiiig IVoiii %

to 1/2 in. Tkansvkksk Load

Wall spcciincii BW T'2 under ti'iuisvcfsc loiid

is shown in (igiire 12. The results lor speci- mens BW-Tl, T2, and T3 are given in lid)l(5s 4 and 5 and in figure 13.

Table 5.-

Effcclt^ of tran^versr luad. vnll liW

Dcscripl idii ul clVi'Cts

Specimen

Tl

Sijecimen .Specimen TS

Load

Deflec- tion Load

Deflec- tion LoadDeflec- tion IW in. in. in. Face not loaded: First trans- verse crack in tlie bond

hclwcen the mortar and the

roiiiTi'lc units alone a hori- ii}intnearmifispan, ..- 40 0. 19 40 0. 20 40 0. 2fi Fufc liiailed: First transverse craclc in the bond between the mortar and the concrete units along

a horizontal joint-. . . 1.50 1. .50 160 1. .53 140 1. .54 Crafl< along the vertical

170 1. 82 1(111 l.Sl

At the maximum load each specimen failed

l)y rupture of all, or all but one, of the wood

splines and half splines about 8 in. above

inidspan. Rupture in the bond between the

?[)()

5^

120

CD

40

1—*! —0-|

0 —0- •

/

( »

1• D

1

1e

1

l7

m

0 12 5

deflection in. Figure 13.

Transverse load on wall BW.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens BW-Tl, n, and TS on the span 7 ft li in.

[11]
Figure li—Wall

specimen BW~12

during the impact

test.

mortar and the units had occurred at most of the horizontal joints in each specimen.

4. Impact Load

Wall specimen BW~I2 diu-ing the impact

test is shown in figure 14. The results are shown in tables 4 and 6 and in figure 15 for wall

specimens BW-Il, 12, and 13. Table 6.

Effects of impact load, luall BW

10

Specimen //

Description of effects

Face not loaded: First trans- verse crack in the bond be- tween the mortar and the concrete units alone; a hori- zontal joint near midspan

Face loaded:

First transverse crack in the bond between the mortar and the concrete units along a horizontal joint near midspan

Crack along vertical mortar

joint Crack in units at midspan.

Failure by rupture of concrete units

" Face did not fail.

Specimen

W

3. 0

3. 5

5.0

7. 5

Specimen IS

2.5 9.5

(-)

0. 30

.30

.76

5, 0

5. 0 7.5

0. n

0^

p-»•

1—O O] o oy

1 1 o

i •

o p o

«• • • •

o a o

1 •f o L •

•

/•—

o /o

/

/

f•

1 ope

f•

1

BW

.69

.70

Q 0.2 0.4 0.6 0.8 deflection in. Figure 15.

Impact load on umll BW.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens BW-Il, 12, and IS on the span 7 ft 6 in.

[12]
The impact loads were applied to the center

of the specimens, the sandbag striking between

the ribs of a unit. After a drop of 10 ft most

of the horizontal joints had cracked but no wood splines had ruptured.

5. Concentrated Load

Wall specimen BW-Pl under concentrated

load is shown in figure 16. The results for specimens BW-Pl, P2, and P3 are shown in table 4 and in figure 17. The concentrated loads were applied midway between the ribs of a unit, from 3 to 4)^

ft from the bottom end of the specimens. After

a load of 1,000 lb had been applied, the in- dentation in specimen PI was 0.006 in.; in specimen P2, 0.005 in.; and in specimen PS,

0.004 in.; and no other eft'ect was observed.

6. Racking Load

Wall specimen BW-Rl under racking load is shown in figure 18. The results for specimens

mo

800

^600

•^400

I

i

"^200

1

/ ••-

1H

1

1»

1

1»

11•

1

1

1 •

1•

1• i 0 0.02 0.04 0.06

indetifafion in. Figure 17.-

Concentrated load on wall BW.

Loarl-iiidi'ntation results for specimens BW-Pl, P2, and PS

Figure 16. —Wall specimen BW-Pl under concentrated load.

[13]
4

»o

1—

o

•

•

o < y0 X <

•

1

o

• o

CO

•

•—

o if/

• o coV

// • c ¥-

FlGVIiK 18.

Wall Sl>ccilNi II B]\ ~IU nmli r riicLiiKj Imiil.

0 0.4 0.8 I.? deformaf/on In./Sff

Figure 19.

Racking load on wall BW.

Load-deformation (open circles) and load-set (solid circles) results for specimens BW-Rl, R2, and RS. The loads

are in kips per foot of actual width of specimen. BW-Rl, R2, and R3 are given in table 4 and in

figaire 19. The deformations and sets shown in figure 19

for a height of 8 ft were computed from the

deformeter readings. The gage length of the

deformeter was 6 ft 6 in. For each of the specimens all or nearly all of the joints in both faces cracked in the bond

between the mortar and the units, and most of the units broke. The first crack in the mortar

occurred in a vertical joint at a load of 1.5 Idps/ft. Under this load the deformation of

specimen Rl was 0.070 in.; of specimen R2,

0.019 in.; and of specimen R3, 0.022 in. The

units began to break at loads of 3.3, 3.0, and

3.0 Idps/ft, respectively. Under the maximum

load each of the specimens failed by crushing

of the units along the loaded edge and buckling

of the middle units of the top course.

The description and drawings of the speci- mens were prepared by E. J. Schell and G. W.

Shaw, of the Bureau's Building Practice and

Specifications Section, under the supervision

of V. B. Phelan, from information furnished

by the sponsor and by inspection of the speci- mens themselves.

The structural properties were obtained from

tests made by the Engineering Mechanics

Section, under the supervision of H. L. Whitte- more and A. H. Stang, and by the Masonry

Construction Section, under the supervision

of D. E. Parsons, with the assistance of the

following members of the professional staff: F. Cardile, H. Dollar, M. Dubin, A. H. Easton,

A. S. Endler, C. D. Johnson, P. H. Petersen, A. J. Sussman, and L. R. Sweetman.

Washington, August 12, 1939.

o

14

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BMSl Research on Building Materials and Structures for Use in Low-Cost Housing 100 BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 100 BMS4 Accelerated Aging of Fiber Building Boards 100 BMS5 Structural Properties of Six Masonry Wall Constructions 150 BMS6 Survey of Roofing Materials in the Southeastern States 150 BMS7 Water Permeability of Masonry Walls 100 BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 100 BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 100 BMSIO Structural Properties of One of the "Kevstone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 1 100 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 100 BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs Sponsored

by Steel Buildings, Inc 150 BMS13 Properties of Some Fiber Building Boards of Current Manufacture 100 BMS14 Indentation and Recovery of Low-Cost Floor Coverings 100 BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Constructions Sponsored by the Wheeling

Corrugating Co 100 BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete Floors, Inc 100 BMS17 Sound Insulation of Wall and Floor Constructions 100 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by

the Harnischfeger Corporation ; 100 BMS19 Preparation and Revision of Building Codes 150 BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored by Connecticut Pre-Cast Buildings Corporation 100 BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National

Concrete Masonry Association 100 BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 100 BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick Manufacturers

Association of New York, Inc 100 BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile Cavity-Wall Construction Sponsored by the Structural Clay Products Institute 100 BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions, Floors,

and Roofs 150 BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction Sponsored by

the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" WaU Construction Sponsored bv The Bender Body

Co : 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Ivlateriab in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas Fir Plywood

Association 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The

Insulite Co 150 BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete-Block

Wall Construction Sponsored by the National Concrete Masonry Association 100 BMS33 Plastic Calking Materials 100 BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 100 BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging 100

[List continued on cover page iv]
BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions with "Red

Stripe" Lath Sponsored by The Weston Paper & Manufacturing Co 10(4 BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and Floors Sponsored by Palisade Homes 10^ BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co 10(i BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co_ 10^ BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored by Knap

America Inc 10«S