Non-Linear Analysis of Multistory RC Irregular Building for Seismic Load by using Response Spectrum Method

A structure can be classified as irregular if it contains irregular distributions of mass, stiffness and strength or due to irregular geometrical configurations. Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. Codes suggests the different limits for these irregularities like as per IS 1893:2002, a storey in a building is said to contain mass irregularity if its mass exceeds 200% than that of the adjacent storey. In case, it is necessary to identify the performance of the structures to withstand against disaster for both new and existing one. This study is concerned with the effects of various vertical irregularities on the seismic response of a structure. The objective of the project is to carry out Response spectrum analysis (RSA) of vertically irregular RC building frame structure by the use of STAAD.PRO software of structure design. This study is limited to reinforced concrete framed structures subjected to seismic loads (dead load, live load and earthquake load). For this, RC frames of G+9 multi-story buildings are considered. All the frames are assumed to be located in zone V. The seismic parameters such as storey drift, base shear, peak story shear and top node displacement of irregular buildings are compared with that of a regular building. Result found from the response spectrum analysis that in irregular shaped building displacements are more than that of regular shaped building. The overall performance of regular building is found better than irregular building. This study may be used for designing new irregular building structures and for analyzing existing irregular building.