Response analysis of hollow core Slab Bridge with different column heights to near-fault seismic motions

The near-fault earthquake motions are characterized by influential velocity impulses, and remarkable permanent displacement. Such unique characteristics can substantially change the induced seismic responses of structures. The current study incorporates near-fault earthquake motions with forward-directivity and fling-step to excite a reinforced concrete (RC) hollow-core slab bridge with varying column heights. The study adopts a RC hollow-core slab bridge having three spans, each 30.0 m long, with a deck width of 11.5 m, a depth of 2.0 m and column’s heights designed to meet a span-to-column height ratio of 2.5 to 5. Three-dimensional numerical models of the bridge are established using the CSI-BRIDGE software and dynamic time-history analysis is used to capture the simultaneous influence of near-fault motions and supporting columns with varying heights on the seismic response of the RC hollow-core slab bridge, under selected earthquake loads. Upon analyzing the seismic response of the excited bridge, the simulation results revealed that a substantial increase in seismic demands of the bridge with more susceptibility to near-fault motions with fling-step than the forward directivity ground motions. This effect is more pronounced for bridge models with taller columns than models with reduced column’s height.