Risk Targeted Seismic Design of RC Frame Buildings

Abstract

The Design criteria specified in Seismic codes implicitly explains the performance objectives and non-linear response of buildings through response. The Response reduction factor is used to reduce the design forces in structure to incorporate non-linear behaviour and capacity in post yield region. The focus of present study is to determine values of performance factors and compare these values with the suggested values from different seismic codes. Risk targeted seismic design utilizes the probabilistic framework to acquire risk levels within the desired limits iteratively. The methodology of probabilistic framework to quantify the seismic performance factor of RC moment-resisting frame is adopted. The non-linear analyses are performed using 22 ground motion sets on 3 RC frame buildings located in seismic zone IV of IS 1893 (2016). The detailed modelling of low and mid-rise buildings is done as per the Indian seismic standards. Validation of analytical modelling at member and global response level are carried out to eliminate propagation of modelling errors in the total uncertainty. The effects of timer period on available response reduction factor, conditional probability of collapse and the annual rate of collapse exceedance have been studied. It has been found that designing RC moment-resisting frame building for the higher time period does not reduce available response reduction neither increases the annual rate of collapse exceedance when other codal provisions, such as capacity design, and Strong column weak beam are followed.