Retracted: Fragility Analysis of Isolation Effect for Plate-Type Elastomeric Bearing on Continuous Girder Bridges with Unequal Height Piers

Most of current vulnerability related researches have focused on the regular bridges with equal height piers, whereas the practical bridge engineering rarely have piers of absolutely equal. This study develops both the component and system fragility of a typical irregular multi-span continuous reinforced concrete girder (MSCRCG) bridge with unequal height piers, which is commonly equipped with the plate-type elastomeric bearings in China. Unlike the conventional deterministic analysis, the seismic fragility function provides a probabilistic approach to quantify the seismic performance of the bridge by accounting for various sources of uncertainty. Moreover, this study applies the direct integration method and Monte-Carlo method to generate the system level fragility function of the bridge engineering. Both the component level and system level fragility functions are used to examine the isolation effect of the common used plate-type elastomeric bearings (PTEB) on the MSCRCG bridges with unequal height piers. Analyses show that it is an efficient and practical method to balance the component fragilities of unequal height piers and decrease the system fragility of the bridge by adjusting the geometric sizes of the PTEBs. In addition, the present study suggests that the stiffness radio between the higher pier-bearing system and the adjacent lower pier-bearing system should also no smaller than 0.75 that is recommended for multi-frame bridge by the Caltrans SDC.