Results of Tests to Determine Racking Resistance of Walls

(1)

Publisher’s version / Version de l'éditeur:

Technical Note (National Research Council of Canada. Division of Building Research), 1962-06-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.

https://nrc-publications.canada.ca/eng/copyright

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la

première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

NRC Publications Archive

Archives des publications du CNRC

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/20359201

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Results of Tests to Determine Racking Resistance of Walls

Hansen, A. T.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=733a3d02-82ae-4ccd-87bd-010fc141d33e https://publications-cnrc.canada.ca/fra/voir/objet/?id=733a3d02-82ae-4ccd-87bd-010fc141d33e

(2)

NATIONAL RESEARCH COUNCIL OF CANADA

DIVISION OF BUILDING RESEARCH

'fE

C

1HIN ][ CAlL

NOT FOR PUBLICATION

NOTlE

ｉｾ

No.

376

FOR INTERNAL USE

PREPARED BY A. T. Hansen in CHECKED BY HBD

co -oper ation with FPRB

APPROVED BY RF L

DATE June 1962

PREPARED FOR _{General information regarding Housing Standards}

SUBJECT RESULTS OF TESTS TO DETERMINE RACKING RESISTANCE OF WALLS

As part of its over -all interest in the structural performance of houses, the Division of Building Research has over the past years examined different wall constructions with regard to their racking

resistance. An extensive series of tests to measure the racking strength of wall panels, some sheathed with various materials and some with interior cladding, has been carried out as a co -operative project of this Division and the Forest Products Research Branch Laboratories. The. results of these tests are the subject of this note. The DBR is indebted to the Forest Products Research Branch for permission to reproduce the results of some of their racking tests, which are shown in Table I together with the test results of this Division.

Racking For ces

Racking resistance of walls is the strength provided by the walls in resisting horizontal forces applied parallel to the direction of the wall. This is an important consideration in resisting wind forces and earthquake forces. It can be measured in the laboratory by applying horizontal loads to the top of a wall panel secured to the floor. The tests are usually conducted on 8 - by 8 -ft panels in accordance with ASTM Standard Method E7Z-6l (Section 37 etc) or a modification of it.

(3)

2

-Results of Racking Tests

Table I indicates the relative effects of each of these elements for some of the more common types of stud wall constructions. Some of the tests were carried out at the Division of Building Research and others at the Forest Products Research Branch laboratories in Ottawa. The test panels were 8 by 8 ft in size and framed in the typical manner with Z _{x 4}

studs spaced 16 in. o. c. The results are the average of tests on three panels in each case.

As well as showing the maximum load carried by the individual panels. Table I also lists the load necessary to produce a l/Z-in. deflection at the top of the panel. The load required to cause this deflection is a

measure of the panel stiffness within a reasonable range of movement. As can be noted from the Table. the stiffness of the panels varies over a wide range.

Panels with horizontal lumber sheathing only, deflected l/Z in. at a load of only 300 lb. The addition of let -in bracing increased the

racking resistance to 450 lb at 1/2 -in. deflection. Since it would not be the usual practice in conventional construction to provide let -in bracing every 8 ft of wall (the length of the test panel), even this modest increase in racking strength at l/Z -in. deflection would not indicate the proportional effect of bracing as used in practice.

With the addition of lath and plaster. the load required to cause a l/Z-in. deflection with a braced panel with horizontal lumber sheathing is 2190 lb. This indicates an apparent increase in the load required to cause a l/Z-in. deflection of 1740 lb which amounts to almost four times the contribution provided by the lumber sheathing and bracing at this deflection. The deflection of the plastered panels was about 1. 9 in. near the failure load. At this deflection the sheathing plus bracing would be contributing about 520 Ib of racking resistance as compared to the failure load of the panel of 5570 lb.

In the case of 3/8 -in. gypsum drywall, the load causing a l/Z -in. deflection of a panel sheathed with horizontal lumber siding and braced, was 1500 Ib which indicated that the drywall alone was contributing 1050 lb of this amount, even though the joints were not taped nor was the gypsum board nailed to the top and bottom plates as would be the case in practice. Near the failure load the panel deflected about 1 in. At this deflection the sheathing plus bracing would be contributing only about 420 Ib to the panel which had a failure load of 2200 lb.

(4)

.'

NATIONAL RESEARCH COUNCIL

CANADA

DIVISION OF BUILDING RESEARCH

ERRATUM SHERr

DBR Technical Note No. 376

by

A.

T. _Hansen

RESULTS OF TESTS TO DETERIVIINE RACKING

RESISTANCE OF WALLS

Please amend Item 3(b) on page 3

to read:

4'

X 8'

_{x 5/16" horizontal}

(rather than vertical as in

copy sent to you).

Margaret A. Gerard

Publications Section

16.7.62

(5)

(6)

-or

3

-TABLE I

SUMMARY OF RACKING TESTS (Nailing shown at end of Table)

.'

..

Wall Cladding Manufactur er Load Causing

ill

Deflection, lb Maximum Load, lb SouTce of

*

Information 1. Gypsum sheathing only (2' x 8' x

!")

A 1,460 2,450 DBR B 1,370 2,670 DBR C 1, 320 . 2,400 DBR 2. Fiberboard sheathing only (a) 4' x 8' X 7/1611 D 1,740 2,620 FPRB vertical (b) 4' x 8' X 1.11₂ E 1,220 1,970 FPRB

e

vertical (c) 25" x 8' x 1.11₂ F 930 1,520 FPRB horizontal (d) 4' x 8' X 5/811 G 1,580 3,825 FPRB homogeneous, vertical ( e) 4' x8' X 7/1611 H 1,860 3,350 FPRB laminated, coated, vertical 3. Douglas ｆｩｾ plywood sheathing only (a) 4' x 8' X 5/1611 1,450 2,220 FPRB horizontal (no blocking·between studs) (b) 4' x Ｘｾ X 5/1611 1,580 2,490 FPRB

\.or

\1..0","01.-

ve:rtieal - fastened

with

li ll

heavy duty

staples spaced 6" o. c. along edges and 1211 _{o. c. along}

inter-mediate supports

*

DBR

FPRB

- Division of Building Research. - Forest Products Research Branch.

(7)

4

-e

TABLE I (cont'd)

Wall Cladding Manufacturer Load Causing Maximum Source

til

Deflection, Load, of

lb lb Information

3.

(c) 4' x 8' X 5/1611 1,950 3,530 FPRB horizontal -edges supported by blocking (one panel tested) 4. Poplar Plywood sheathing only (a) 4' x 4' x 5/16" - A 1,830 3,000 FPRB with edges supported by blocking (b) 4' x 8' x 5/16" B 1,600 3,650 FPRB horizontal - with edges supported by blocking (one panel tested)

5. Wood particle board sheathing only (a) 4' x· 8' x 1._2-II 2,480 4, 140 FPRB vertical (b) 4' x8' x 3/8" 1,670 2,790 FPRB (c) 4' x 8' X 5/1611 1,790 2,490 FPRB vertical

6. Lumber sheathing only

(a) Diagonal 1,930 4,470 FPRB

application

(b) Horizontal 300 750 FPRB

application

(c) Horizontal with 450 1, 120 FPRB

1 x 4 let -in brace across three stud spaces

(8)

5

-e

TABLE

I (cont'd)

Wall Cladding Manufacturer Load Causing Maximum Source

i"

_Deflection, Load, of

lb lb Information

7.

Lumber sheathing with interior cladding

(a) Same as 6 (c) 1,510 2,200 DBR

but with 3/8" gypsum board finish. Joints not taped, and nailed to studs only

(b) Same as 6 (c) 2,190 5,570 DBR

but with lath and plaster on other side (c) Same as 6 (c) 987 1,923 FPRB but with 4' x 8' X ｾＬＮ Fiberboard (Interior Board) on other side applied vertically 8. Interior 'Fiberboard 640 898 FPRB 4' x 8' x

i

II vertical (no sheathing)

Nailing of panels was as follows:

Fiberboard sheathing

Gypsum board

sheathing

1 3/411 _{roofing nails - 7/16}11 _{head spaced}

3" o. c. at supported edges and 611 _{o. c. at}

intermediate supports

1 3/4" roofing nails, 11 g. spaced 4" o. c. on flll studs

(9)

TABLE I (cont'd)

Plywood

Particle board

Board sheathing

ｇｹｰｳｾｭ lath

Gypsum dry wall

Interior Fiberboard

6

-I 3/4" common nails spaced 6" o. c. on supported edges, 1Z" o. c. at intermediate supports

ZIt common nails spaced 6" o. c. on supported edges, 1Z" o. c. at intermediate supports

Zt"

common nails -

Z

per bearing for FPRB tests

ZIt common - Z per bearing for DBR tests

1

i"

lathing nails - 4 per lath per stud'

support

Ii"

dry wall nails 8" o. c. applied to studs only

It"

finishing nails spaced 4" o. c. along edge supports and 8" o. c. along intermediate supports.