Seismic Performance Assessment of Irregular RC Building

Abstract

Damage to irregular structures caused by asymmetry in plan has been observed during many major and minor earthquakes during the past. The non-coincident center of mass and stiffness in a structure generate plan asymmetry which causes torsional vibration resulting in severe damage to structural components in the more laterally flexible regions of the structure. Modelling plays a very important role in design and analysis of structures. In the present study, a typical irregular plan of building with 5-storey is considered and is assumed to be located on medium soil condition and seismic zone V. The building is analyzed by using response spectrum analysis and designed as special moment resisting frame as per the specifications of Indian Standard. Further, the performance of building is assessed using Non-linear static procedure i.e. static pushover analysis as per ASCE-41. In addition to this the response reduction factor (R) of considered model is also evaluated. It is concluded that, for irregular buildings considering response reduction factor R same as that provided in Indian seismic code is inappropriate and the value should be less than 5.