Risk assessment of seismic vulnerability of RC framed buildings due to asymmetricity

Existing buildings designed as per older seismic codes shall not comply to seismic demands imposed by current codes. Seismic evaluation shall be employed to address such deficient structural systems to assess their expected performance. Geometric irregularities resulting in asymmetricity attract additional forces due to torsion and therefore become more critical. The current study focuses on risk assessment of seismic vulnerability of a typical 15 storey RC framed building with asymmetric plan configuration using Indian code. The study illustrates the procedure of seismic evaluation of asymmetric buildings through preliminary and detailed stages, in a step-by-step manner. Results show that building frames become seismically vulnerable when torsional effect is included in the analysis. It is imperative to conduct detailed seismic evaluation of asymmetric buildings to examine their seismic vulnerability though preliminary evaluation gives an approximate idea of their structural safety.