Collapse Capacity of Ordinary RC Moment Frames Considering Mainshock-Aftershock Effects

ABSTRACT

The effect of mainshock-aftershock (MS-AS) sequences on seismic performance of ordinary reinforced concrete (RC) moment frames (ORCFs) is studied by considering various levels of mainshock damage represented by maximum inter-story drift (MID) parameter. Incremental dynamic analysis (IDA) is performed to extract collapse capacity of structures under aftershock records after imposing the intended mainshock damage. The study results indicate that a smooth reduction in aftershock collapse capacity occurs due to increase in mainshock damage level. Regression equations are also provided to aid in predicting the aftershock collapse capacity in presence of various mainshock damage levels.

KEYWORDS:

• Mainshock-Aftershock
• incremental dynamic analysis
• collapse state
• fragility curve
• median collapse capacity
• capacity reduction ratio