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Re: masonry shear walls

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Andrew,

As a rule of thumb, I use the entire wall if the pier is caused by a window
opening, (i.e. masonry above and below opening), and the pier length itself if
the jamb of the pier is a door to the bottom of the wall. This is
conservative, especially if the wall itself is tall, (probably applicable if
the door is 6'-8" high and the wall is only 8' high).

Larry Hauer S.E.

On Thu, 2 Jan 2003 17:06:31 -0500 "Andrew D. Kester" <andrew(--nospam--at)baeonline.com>
wrote:

> Ok, here is an easy one for all of you
> reinforced masonry wall gurus. I am
> mainly dealing with work in FL, so no seismic
> but high lateral wind loads.
> 
> When looking at a segment of a shear wall, or a
> pier, and doing overturning
> analysis on that pier, what portion of the dead
> load do you  include to
> resist overturning of that pier? I have been
> taking the dead load of the
> entire wall and the roof dead load X 2/3, but I
> guess UBC/IBC and some other
> codes may use 0.85. That is not really my
> question as much as do you assume
> the wall acts as a unit in overturning, so that
> you include the dead load
> from the entire wall? I have been and I am
> wondering what others are doing.
> From the texts I have researched this seems to
> be the normal practice.
> 
> 
> Finally, the compressive jamb.. The traditional
> simple formula is C= T + P,
> where C= compressive force, T= tensile force,
> P= axial load (roof load, wall
> weight). But on a fairly long one-story wall,
> it seems only logical to use
> the axial load P which is directly applied to
> THAT JAMB, not of the whole
> pier or wall segment. Also you assume that the
> entire compressive force is
> resisted by the end jamb which is an
> oversimplified and conservative version
> of the triangular stress pattern in the wall.
> So what I have been doing is
> after my shear wall analysis, I take the T/C
> force from overturning, and
> then add that into the worse case wall analysis
> (includes lateral loading
> and axial loads), then check that wall segment.
> Often in walls with small
> height to length ratios we are talking about
> less then a few kips. This
> often does not require anything additional to
> the jamb, but maybe adding two
> filled cells instead of one. This may be a
> little conservative, but it is
> easy and quick and the results seem quite
> economical as many times it is
> just a check. I do the same for tensile
> analysis, and maybe I add an
> additional bar.
> 
> Clear as mud? Any comments or suggestions or
> "the way I do it" s  ????
> 
> Thanks in advance ladies and gents, and happy
> new year to all of you.
> 
> Andrew Kester, EI
> Longwood, FL
> 
> 
> 
> 
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