Characterization of Near-Fault Effects on Potential Cumulative Damage of Reinforced Concrete Bridge Piers

The objective of this study is to characterize the potential damage of near-fault ground motions on reinforced concrete bridge piers, providing information for engineering practice. To achieve this objective, 200 real near-fault pulse-type records and a bridge pier were selected. The same number of real far-fault ground motions was also selected for comparison. Inelastic time history and damage analyses were performed for the pier subjected to the selected near-fault and far-fault ground motions. The obtained results showed that more than 91% near-fault motions caused the pier to collapse while the pier survived under almost all far-fault motions. The responses of the pier under near-fault motions were characterized by one or few large hysteretic cycles. The damage indices of the pier subjected to near-fault ground motions increased rapidly when the pier underwent pulses of near-fault motions, and the pier damage was mainly caused by pulses. Collapse of the pier subjected to near-fault motions occurred at the pulse time. The duration to collapse, which was defined as the duration from light damage to collapse, of the pier under near-fault motions was extremely short (approximately 2.3-2.5 s). These special and negative structural damage characteristics of near-fault ground motions should be considered in designing and mitigating seismic hazards for structures located in near-fault regions.