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Re: Shear Wall Design

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        Allow me to be quarrelsome and impatient with your questions, in
recognition of your being newly out of school and presumably well trained in
analytic inquiry, and not yet filled with lazy prejudices the way
experienced engineers so often are.

At 03:08 PM 11/16/99 EST, you wrote:
>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 overturning 
>also increases the shear in plf on the wall, or else an element within the 
>wall will not be in equilibrium.

        OK, do you mean dead load applied (or superimposed) uniformly along
the length of a shear wall, or dead load connected to a vertical boundary of
the wall?

        Do you mean to compare a wall that has resistance to overturning to
a wall that does not?

        Do you mean that the existence of the dead load you have in mind
CAUSES more shear in plf in the wall, or that it increases the shear in plf
that the wall IS ABLE to resist before an overturning instability results?

        Do you mean that the existence of dead load in whatever position
increases the shear strength of the material or fasteners that resist shear
stress? 
        --------------

>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 
>insight.
        
        The first sentence above refers rather imprecisely to "the topic"
and to "it."  There is little chance of a useful comment back on such a
vague description of what is of interest. Precision in language, and in
perceptions, is even more important than precision in numbers, which is a
mere follow-on activity. 

        Much insight is available to you by your own taking stock explicitly
of what you know and what you don't know, setting up a simple free-body
diagram of the wall and also of elements of it, and proceeding to apply
principles of mechanics of the classic sort: statics and strength of
materials. What's true with shear walls will unfold for you as you proceed
and experiment. 

        There is a good chance the structural engineers you have spoken to
were not willing to actually think through the problem and its
ramifications, and instead just shot out "beliefs" from their mental hips.
Such is the most commonplace sin in this supposedly august profession. The
1997 UBC (and many of its users) suffer badly from just this sin on the part
of its authors. 

Charles O. Greenlaw  SE   Sacramento CA