7/21/2019 How It Works the Shear Waals

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7/21/2019 How It Works the Shear Waals

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LATERAL

The primary lateral fo

from an earthquake o

high-wind event caus

simultaneous uplift,

compression, and slid

forces.

UPLIFT

Lateral forces try to r

the wall off the found

creating uplift on one

of the wall assembly.

COMPRESSIO

As one end of the wa

experiencing uplift, t

opposite end is unde

compression. These l

alternate as the build

shakes back and fort

SL IDING

RESISTANCEThe few anchor bolts

are present try to cou

the lateral force, whic

to slide the wall off th

foundation, but the b

are ineffective.

STRENGTH IN DETAILSShear walls should be thought of as a bal-anced system with components that coun-

ter the forces exerted upon it. These arethe basic components of a shear wall. An

engineer will fine-tune wall assemblies tothe specifics of a home and site, which will

dictate such details as nail size and nailingschedule and blocking size and orientation.

COMPRESSION

Edge nailsplaced every

3 in. should notbe driven within

38in. of the

edge of theplywood.

The sill platesand foundationwalls must be in

solid condition tosupport the shearwall when under

compression.

To increasethe stiffness of

the wall assemblyand to hold the shearwall together, 12-in.

plywood should extendfrom the top of the top

plate to the bottomof the bottom

plate.

Fullround-head

nails attach plywood tostuds. Studies show thatnails set flush to plywood

surfaces perform farbetter than countersunknails. Never use screws,

which are morebrittle than

nails.

Anchor boltsset with 3-in. by

3-in. washer plateskeep first-floor walls

from sliding offthe foundation.

SLIDING

RESISTANCE

www.finehomebuilding.com OCTOBER/NOVEMBER 2011www.finehomebuilding.com

COPYRIGHT 2011 by The Taunton Press, Inc. Copying and distribution of this article is not permitted.