Special Design Provision for Soft First Storey

To safeguard the soft first storey from damage and collapse code provides two alternative design approaches:

1) The dynamic analysis of the building is to be carried out which should include the strength and stiffness effects of infills as well as the inelastic deformations under the design earthquake force disregarding the reduction factor R.

2) The  building  is  analyzed  as  a  bare  frame  neglecting  the  effect of   infills   and,   the   dynamic forces  so  determined  in columns   and   beams   of  the   soft (stilt)  storey are to be designed for 2.5 times the storey shear and moments:

or the shear walls are introduced in the stilt storey in both directions of the building which should be designed for 1.5 times the calculated storey shear forces.