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Shear Wall Design

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In the design of reinforced concrete high-rise buildings, with shear wall-frame dual system,
seismic zones 2 or 3, using ETABS.  I frequently encounter the situation where the ETABS
 analysis results show quite large horizontal shear forces in shear walls under the action of
dead loads (and also live loads). This is so even for regular buildings. In fact, in some shear
walls, the shear forces under dead loads only are more than the shear forces obtained under
 seismic loads, especially in lower floors. The situation is further aggravated if there are basements.
Designing these walls for the usual Code (UBC) specified ultimate load combinations
(dead +live +seismic) results in very high shear reinforcement values, and sometimes the
design shear exceeds the max allowed. If we neglect the shear due to gravity loads, the walls
 can easily resist the shear due to seismic effects, using appropriate horizontal reinforcement.
Usually, floors are modeled as plate elements with rigid diaphragms and shear walls are modeled
 as shell elements, all with proper meshing and line constraints.  Flexure is generally under control.
 It is strange that almost all the publications I have seen do not mention the horizontal shear
 forces in walls due to gravity loads and only consider the shear forces under seismic loads
while designing the walls for shear. I would very much like to hear the views and experiences
 of others in this regard. Please note that I am talking about buildings of  25 stories and above.