Aftershock Fragility Assessment of Continuous RC Girder Bridges Using a Modified Damage Index

Aftershock fragility is usually calculated conditioned on a range of potential post-mainshock damage states. The can be identified using indices, the latter being frequently associated with displacement-based parameters such as maximum drift ratio or residual displacement. However, when reliable simulation structural system in specific state objective numerical study, indicators may not assure structure experiencing homogeneous level due to different mainshocks characteristics, which induce aftershock results unreliable. Along these lines, current study presents evaluation methodology mainly used for assessment. It aims reduce variation levels derived by mainshock seismic motions. presented herein includes: (i) introduction index defined comparing monotonic pushover curve intact and post-earthquake damaged structure; (ii) description finite element (FE)-based scheme that enables quantify proposed index; (iii) deterioration-related modeling technique capture both strength stiffness degrading performance systems exposed earthquake-induced excitations. essential support FE-based quantification index. This primarily calculating assessment multi-span RC continuous girder bridge. back-to-back incremental dynamic analysis framework uses larger number mainshock-aftershock artificial sequences generate curves. AS obtained via MBDI are compared terms ability capacities but collapse same aftershock. comparison shows more robust relationship capacity. found MBDI, well its approach this effective predictor than widely indices