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# Civil Engineering/Shear Wall

Question
I am having following question relevant to ETABs

1) what is the difference in column and shear wall in reality ..i read that one is area section ant the later is frame ..but i am still not sure that both can take axial loads and moments but are differed from each other ..kindly elaborate

2) while modelling a shear wall in ETABs , e.g at the corner of building the shear wall from perpendicular direction meet there ..is there requirement of providing a column at their junction ..as a did this in order to support beams on that column instead of resting it on shear wall..

3) i am having an irregular building ..if i reduce the percentage difference between the center of mass and center of rigidity up to 12-14 % is it fine or i should further bring them closer to each other ???

4) In designing the Raft of 3o'x60' (under entire area) for the bullring the soil reaction is coming more than allowable bearing pressure , i cant increase the dimensions of the raft anymore..what could be the solution ..the Bearing capacity of site is good ( 1.8 t /ft2)...what could be other solution ??

Hi Zain,

1. They act in the same way, except that when the column L:W ratio exceeds about 4 to 5, it should be considered a wall (different codes have slightly different rules)

2. You can rest on the corner, but this should be treated as a boundary zone, with extra rebar (min. 1%, with closely spaced links, at 100mm centers). If you model a nominal column (say 200x200) at the corner, the ETABS output will guide you on the %age rebar required at the corner.

3. That should be fine.

4. Either stiffen up the raft, so that the maximum pressure is spread over larger area, or deepen the foundation to get better soil bearing capacity or get benefit from extra capacity due to soil removed. e.g. for every meter removed you will gain an extra 18-20 kN/m2 bearing capacity.
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