Design of mutli-storied building with and without soft stories using STAAD Pro

Soft stories are one of those structures containing structural irregularities, especially vertical irregularities. Soft stories case is generally related to sudden and abrupt change or increase in the stiffness of the storey. This soft storey is soft target for dynamic displacing forces, especially in the horizontal direction, due to its more flexibility in nature and leads to collapse of structure which it supports and, thus ultimately whole structure collapse in shear. If not designed well, soft storey causes failure not only due to external forces but also to drifting of mass by external lateral forces, from its original position. In the present study, the analysis of the ten-storey building with or without soft storey was carried out to investigate the effect of soft storey under identical loading conditions as per Indian standards. The previous studies were carried out on the structures considering ground floor as soft storey. Structure has been modeled and analyzed using well established software Staad-Pro V8i. Results showed that drift of M5 type structure was increased by 1.6 times approximately M0 type structure. Base shear was reduced by due to reduced stiffness by 7.5% and time period in the orthogonal direction increased by 5%.