The program of research on buildnig materials and structures undertaken by the

National Bureau of Standards is planned with the assistance of the following advisory

committee designated by the Subcommittee on Design and Construction of the Central

Housing Committee.

TECHNICAL RESEARCH GROUP

Walter Junge, Federal Housing Administration, Chairman

A. C. Shire, United States Housing Authority, Vice Chairman

A. G. Bear, Vincent B. Phelan,

Veterans' Administration. National Bureau of Standards.

Pierre Blouke, ^ Poynton Home Owners' Loan Corporation. '

* » ^ t' «. • C. W. Chamberlain, ^^^^ «^ ^^^^^

Procurement Division. John H. Schaefer,

Jos. M. DallaValle, Procurement Division.

Public Health Service.

Hugh L. Dryden,

National Biu"eau of Standards.

G. E. Knox, Elsmere J. Walters,

Bureau of Yards and Docks, Navy Quartermaster Corps, War DepartDepartment. ment.

Sterling K. March, Secretary

The program is administered and coordinated by the following staff committee of

the Bureau:

Hugh L. Dryden, Chairman

P. H. Bates W. E. Emley A. S. McAllister

H. C. Dickinson G. E. F. Lundell H. S. Rawdon

The Forest Products Laboratory of the United States Department of Agriculture

is cooperating with the National Bureau of Standards in studies of wood constructions.

George W. Trayer,

United States Forest Service.

How To Purchase

BUILDING MATERIALS AND STRUCTURES REPORTS

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UNITED STATES DEPARTMENT OF COMMERCE • Harry L. Hopkins, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS16

Structural Properties of a "Tilecrete" Floor Construction

Sponsored by Tilecrete Floors, Inc.

by HERBERT L. WHITTEMORE, AMBROSE H. STANG,

and CYRUS c. fishburn

ISSUED march 24, 1939

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

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

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • 1939

FOR SALE BY THE SUPERINTENDENT O F . D O C U M E N T S , WASHINGTON, D. C. • PRICE 10 CENTS
Foreword

This report is one of a series issued by the National Bureau of Standards on the struc- tural properties of constructions intended for low-cost houses and apartments. Practically aU of these constructions were sponsored by groups within the building industry

wliich advocate and promote the use of such constructions and which have built and submitted representative specimens as outlined in report BMS2, Methods of Deterrnining

,

the Structural Properties of Low-Cost House Constructions. The sponsor is responsible

for the representative character of the specimens and for the detailed description given

in each report. The Bureau is responsible for the accuracy of the test data. j This report covers only the load-deformation relations and strength of the structural ' element submitted when subjected to transverse, impact, and concentrated loads by

standardized methods simulating the loads to wliich the element would be subjected in

actual service. It may be feasible to determine later the heat transmission at ordinary

temperatures and the fire resistance of tliis same construction and perhaps other properties.

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

and BMS2. The teclmical facts on tliis and other constructions provide the basic data ' from wliich arcliitects and engiueers can determine whether a construction meets desired '

performance requirements.

Lyman J. Briggs, Director.

[Ill
Structural Properties of a "Tilecrete" Floor Construction

Sponsored by Tilecrete Floors, Inc.

by HERBERT L. WHITTEMORE, AMBROSE H. STANG, and CYRUS C. FISHBURN

CONTENTS

Page

Foreword ii

I. Introduction 1

II. Sponsor and product 2

III. Specimens and tests 2

IV. Floor ^TT -.-i 2

1. Sponsor's statement 2

(a) Materials 2

i For the program on the determination of the structural properties of low-cost house constructions, Tilecrete Floors, Inc., submitted six specimens representing

their "Tilecrete" floor construction. The specimens were subjected to transverse, impact,

and concentrated loads. For each of these loads three

I like specimens were tested, the concentrated-load tests being made on undamaged portions of the specimens

used for the impact tests. The deformation under load and the set after the load was removed were measured

for uniform increments of load, except for concentrated

loads, for w'hich the set only Mas determined. The

strength under transverse load was also determined.

The results are presented graphically and in a table.

I. INTRODUCTION

In order to provide teclmical facts on the

performance of constructions wliich might be

used in low-cost houses, to discover promisingconstructions, and ultimately to determine the

properties necessary for acceptable performance, the National Bureau of Standards has

invited the building industry to cooperate in a program of research on building materials and

structures for use in low-cost houses and apartments. The objectives of this program are described in report BMSl, Research on Building Materials and Structures for Use in LowCost Housing/ and that part of the program

relating to structural properties in report BMS2,

1 Price 10 cents. See cover page II.

Page IV. Floor ^VF—Continued.

1. Sponsor's statement—Continued.

(b) Description 3

(c) Comments 3

2. Transverse load 4

3. Impact load 5

4. Concentrated load 6

V. Selected reference 0

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

Conventional wood-frame constructions, in- cluding those for floors, have been subjected by

the Forest Products Laboratory of the United

States Department of Agriculture to a series of

standardized laboratory tests to provide data on the properties of some constructions for which the behavior in service is generally known.

These data will be given in a subsequent report

in tliis series. This report describes the structural properties

of a floor construction sponsored by one of the

manufacturers in the building industry. The

specimens were subjected to transverse, impact,

and concentrated loads, simulating loads to wliich the floor of a house is subjected. In

actual service, transverse loads are applied to

floors by furniture and by the occupants;

impact loads by objects falling on the floor or by

persons jumping on the floor; and concentrated

loads by furniture, for example, the legs of a

piano.

The deformation and set under each increment of load were measured because the suitability of a floor construction depends in part on its resistance to deformation under load

and whether it returns to its original size and

shape when the load is removed.

2 Price 10 cents.

1_66S0°—39 [1]
II. SPONSOR AND PRODUCT Table 3.

Mechanical properties of the steel The specimens were submitted by Tilecrete

Floors, Inc., St. Louis, Mo., and represented

their "Tilecrete" floor construction. The floor construction consisted of expanded steel joists,

tile fillers, concrete fill, and a wood-block

finish floor.

III. SPECIMENS AND TESTS

The floor construction was assigned the

symbol AW, and the specimens were assigned

designations in accordance with table 1.

Table 1.Specimen designations

Specimen designation

Tl, T2, T3.

II, Jt, IS..-. PI, PS, PSLoad

Transverse Impact

Concentrated _

Load applied

Upper face. Do.

Do.

" These specimens were undamaged portions of the specimens used fo the impact tests. The specimens were tested in accordance with

BMS2, Methods of Determining the Structural

Properties of Low-Cost House Constructions.^

This report also gives the requirements for the

specimens and describes the presentation of the

results of the tests, particularly the loaddeformation graphs.

The specimens were tested on May 2 and 3, 1938, when the age of the concrete fill was 28

days. The sponsor's representative witnessed

the tests. IV. FLOOR AW

1. Sponsor's Statement

(a) Materials

Steel. —Open -hearth, hot -rolled, I-beams

made by the Carnegie-Ilhnois Steel Co. The

chemical composition of the steel is given in

table 2 and the mechanical properties in table 3

.

Table 2.

Chemical composition of the steel

Element

Carbon Manganese

Phosphorus

Sulfur

2 Price 10 cents.

Content

Percent

0. 19 .46

.010 .028

Yield point Tensile strength Elongation in 8 in.

/6/)7!.2 Percent

37, 070 62, 540 29

The I-beams were expanded hot to form

joists by the Bates Expanded Steel Corp. The

joists were straightened by rerolling.

Welds.—Arc welds made with low-carbon

welding rods.

Tile.—Special structural clay floor tile, fourcell, 4 by 16)^ by 12 in., as shown in figure 1, of northern surface clay, shell tliickness % in., web tliickness % in.; compressive strength on

end, 3,500 Ib/in.^ of net area. "Half" tile, 4 by 8%6 by 12 in., were cut from full-size tile to include the entire center web.

The absorption of the tile, determined by the

Masonry Construction Section of the National

Bureau of Standards in accordance with the

American Society for Testing Materials Standard C 112-36,-* was 21.8 percent for the 24-lu'

J Am. Soc. Testing Materials Standards, pt. 2, p. 183-186 (1936).

Figure 1.

Tile and "half" tile.

[2]
cold test and 22.3 percent for the 1-hr boil test. Concrete.—Truck-mixed, containing 1 part

Portland cement, 2.5 parts dry sand, and 4 parts

dry gravel, by weight. The concrete was

delivered in two batches.

The following properties of the concrete were

determined by the Masonry Construction Section of the National Bureau of Standards. For

each batch the slump was determined and six 6- by 12-in. cylinders were made. Three cylinders were cured with the floor specimens and

the other three were stored in the concrete- curing room at 70° F and relative humidity of

95 to 100 percent. The compressive strength

of the cylinders was determined on the day the

corresponding floor specimens were tested, at an age of 28 days. The physical properties of

the concrete are given in table 4.

Table 4.Physical 'properties of the concrete

bottom of each bl()cl<. "Bruce Finished Block."

E. L. Bruce Co.'s

Batch Slump

Compressive strength

Cylinders cured with

floor specimens

Cylinders

stored in concrete- curing room

1

in.m 2, 150

2, 320

2, 290

2 2, 930

Mastic.—Asphalt base. E. L. Bruce Co.

Wood.—Oak, red, clear, plain-sawed, parquetry flooring, 9- by 9-in. blocks, consisting

of four strips of ^%2- by 2}^-in. tongued-andgrooved flooring, fastened together by glue

and by two sheet-steel splines in kerfs in the

(6) Description

The floor specimens were 12 ft 6 in. long,

4 ft 5 in. wide, and 6% in. thick. Each specimen consisted of three steel joists. A, as shown

in figure 2, with structural-clay-tilc fillers, B,

and a concrete fill, C. The fill was covered

with mastic, D, on wliich a wood parcjuetry

finish floor, E, was laid. The price of this construction in Waslungton,

D. C, as of July 1937, was $0.37/ftl

Joists.—The joists. A, were expanded steel I-beams, 6 by 1^ in., 12 ft 6 in. long, 4.22

lb/ft, "Bonderized" finish. The joists had

stift'eners welded to each end, as shown in figure 3. Tile fillers.—Tile fillers, B, were placed between the joists, and "half" tile along each

edge of the specimen.

Fill.—The fill, C, was concrete, 2 in. thick,

screeded level with the upper flanges of the

joists. The concrete was batch 1 for speci- mens II, 12, and Tl and batch 2 for specimens

73, T2, and ^3.

Mastic.—Mastic, D, was applied with a brush to the upper face of the specimen.

Finish floor.—The finish fioor, E, consisted of wood-block flooring laid in the mastic. - .

(c) Comments

"Tilecrete" floors have been used in approximately 280 buildings up to October 1, 1938.

Figure 2.

Floor specimen

AW.

A, joist; B, tile filler; C, fill; D, mastic; E, finish floor.

AiV

[3]
Figure 3.

Expanded steel joist. About 80 percent of these buildings were

dwellings.

The joists are designed to be framed into con- ventional masonry or steel buildmgs without

the use of temporary supports during erection.

Plumbing, electric conduit, and air ducts may

be placed in the floor before the concrete fill is poured. The concrete fill is poured directly on the tile and steel without the use of forms.

Any type of finish floor may be used over the

concrete fill. Typical finish floors are (a) wood

blocks laid in mastic, (b) wood flooring fastened

to wood sleepers set in the concrete, (c) linoleum, (d) concrete, (e) terrazzo, and (f) floor tile. The ceiling may be finished with plaster

applied in two coats. The scratch coat containing fibered plaster is applied directly to the

tile. The usual white finish coat is applied over the scratch coat.

2. Transverse Load

Floor specimen AW-Tl under transverse load

is shown in figure 4. The results for floor speci- mens AW-Tl, T2, and T3 are shown in table 5 and in figure 5.

Table 5.

Structural properties of floor AW

[Weight, 51.51b/ft2]

Load

TransverseConcentrated _ _ _

Impact.

Load applied

Upper face; span, 12 ft 0 in. Average

Upper face.-

Average.

Upper face; span, 12 ft 0 in. Average

Speci- men

desig- nation

TlT2

TS

PIP2

PS

Maxi- mum

height of drop

"10.0

«10.0 "10.0

«10. 0

Maxi- mum

load MP

435 438

444

439

lb "1000

»1000 "1000

"1000

Specimen did not fail. Each of the specimens failed by yielding of the

lower flanges of the joists, as indicated by

600

'500

400

300

yoo

^/OO

0

•• o

/

Figure 4.Floor specimen AW-Tl under transverse load.

0 OA 0.8 1.2

deflection in. Figure 5. —Transverse load on floor AW

Load-deflection (open circles) and load-set (closed circles) results for specimens AW-Tl, Tt, and TS on the span 12 ft 0 in.

[4]
Liiders' lines, followed by cracking of some of

the tile fUlers and cracking of the concrete fill at joints between the tiles. The Liiders' lines were observed at loads of 390, 383, and 360

lb/ft 2 for specimens Tl, T2, and T3, respectively. In addition, for specimen the finish

0 0.2 OA 0.6

def/ecfion in. Figure 7.

Impact load on floor AW.

Height of drop-deflecticn (open circles) and height of drop-set (closed

circles) results for specimens AW-Il, 12, and IS on the span 12 ft 0 in.

floor separated from the concrete fill between

the loading rollers.

3. Impact Load

Floor specimen AW-Il durmg the impact

test is shown in figure 6. The results for floor specimens AW-Il, 12, and 13 are shown in

table 5 and in figure 7. The impact loads were applied to the center

of the upper face of each specimen so that the

sandbag struck the finish floor directly over the

Figure 8.Floor specimen AW-P2 under concentrated

[5]
center joist. The sets after a drop of 10 ft were

0.023, 0.021, and 0.022 in. for specimens II,

12, and 13, respectively, and no other effect was

observed.

4. Concentrated Load

Floor specimen AW-P2 under concentrated

load is shown in figure 8. The results for floor specimens AW-Pl, P2, and P3 are shown in

table 5 and in figure 9.

'1000

\800

600

o

I 200 o

Oi

» -©—

• •

0- < •»

9 I

«

1 —

•

•

—•- VB 0.04 0.08

ino/enfcff/on

0.12

in.

The concentrated loads were applied to the

finish floor of each specimen near a corner of one of the inner blocks of flooring. The indentations after a load of 1 ,000 lb had been applied were 0.089, 0.049, and 0.036 in. for specimens

PI, P2, and P3, respectively, and no other

effect was observed.

The sponsor supplied the information contained in the sponsor's statement. The drawings of the specimens were prepared by E. J. Schell and G. W. Shaw of the Bureau's Buildmg

Practice and Specifications Section, under the

supervision of V. B. Phelan. That Section also cooperated in the preparation of the report.

The structural properties were determined by

the Engineering Mechanics Section, under the

supervision of H. L. Wliittemore and A. H.

Stang, and the Masonry Construction Section,

under the supervision of D. E. Parsons, with the

assistance of the foUowmg members of the professional staff: C. C. Fishburn, F. Cardile,

R. C. Carter, H. DoUar, M. Dubin, A. H. Easton,

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

V. SELECTED REFERENCE

Brick and Clay Record, 93, No. 2, 26 (1938).

Washington, December 7, 1938.

Figure 9.

Concentrated load on floor AW.

Load-indentation results for specimens AW-PI, PS, and PS. o

[6]
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