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RE: Shear Wall Design

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If you are considering the distribution of shear by flexible diaphragm
methods (tributary width) then the dead load on the wall will have been
calculated in the lateral load. What you may not have considered is the
lateral weight of the wall (especially for one story buildings on a slab)
which contributes to the overturning of the wall.
Therefore, you are permitted to consider 85% of the dead load on the wall
(for seismic) and 100% when wind governs to resist uplift on the wall (this
may have changed in the 97 UBC but I have not looked lately). With this
said, you would consider the dead load to the wall (85% or 100% depending on
wind or seismic), the weight of the wall itself to resist uplift, the
lateral force as a percentage of the dead load tributary to the wall applied
at the top plate or some other designated drag location, and the lateral
weight of the wall itself applied at the center of the wall (horizontal).
Summing forces around one end will give you the uplift reaction (if any
exists). Summing forces in each direction will give you reaction at the
other end and the shear applied at the sill of the wall. Your system is now
in equilibrium.
Dennis S. Wish, PE
SEConsultant(--nospam--at) <mailto:SEConsultant(--nospam--at)>
(208) 361-5447 Efax

-----Original Message-----
From: BDWOLF123(--nospam--at) [mailto:BDWOLF123(--nospam--at)]
Sent: Tuesday, November 16, 1999 12:08 PM
To: seaint(--nospam--at)
Subject: Re: Shear Wall Design

I am a first year civil engineering graduate and I have a few general
questions about shear walls.

1.  It is my general understanding that using dead load to resist
also increases the shear in plf on the wall, or else an element within the
wall will not be in equilibrium.

I have spoken to quite a few structural engineers about the topic and some
believe in it and others don't.  Maybe someone out there could provide some


Andrew Arnold
Arnold Engineering