Influence of ground motion duration on seismic behavior of RC bridge piers: The role of low-cycle fatigue damage of reinforcing bars

•Impact of ground motion duration on the seismic behavior of RC bridges is quantified.•Role of low-cycle fatigue damage of reinforcing bars in the impact of duration is identified.•An advanced material-level damage index is used to account for both the strain and fatigue damage.•Stain damage controls under short-duration motions, while fatigue damage may control under long-duration motions.•Fatigue damage is more prominent under more severe damage states of bridges against long-duration motions.