Analysis of the Effect of Mainshock-Aftershock Sequences on the Fragility of RC Bridge Columns

The mainshock (MS) is often accompanied by a number of aftershocks (AS). existence AS may cause the seismic demand to be greater than MS. In order better evaluate impact AS, this paper takes RC columns as research object and performs incremental dynamic analysis (IDA) on actual recorded mainshock-aftershocks (MS-AS). Park–Ang model damage index are used quantify effect MS respectively. fragility parameters such reinforcement ratio, axial compression ratio shear-span carried out results show that MS-AS Besides, column gradually increases with increase decreases ratio. When design grade 7, 8, 9 degree, maximum rate additional caused 13, 15% MS, in medium damaged severely state, growth can estimated 12.7 11% different states under action Reducing pressure greatly reduce probability states. comprehensively considered select appropriate design, according condition column.