Seismic failure mode of coastal bridge piers considering the effects of corrosion-induced damage

Coastal bridges exposed to an aggressive environment are vulnerable to corrosion damage, which reduces the seismic resisting capacity of the structures. Focusing on the corrosion varying along the column height of the coastal bridge piers, this paper investigates the time-dependent failure mode and equivalent plastic hinge length of the aging bridge piers under seismic excitation in the whole life cycle. First, the possible seismic failure modes and the method to estimate the equivalent plastic hinge length are analyzed and discussed. Then, the corrosion initiation time and performance deterioration of the reinforcement are presented. After that, the finite element models of the sound and aging bridge piers are introduced based on the OpenSees software package and the time-dependent constitutive models of the reinforcement. According to the proposed flowchart of the computational procedure, a numerical simulation is conducted to investigate the plastic hinge evolution process of the coastal bridge pier. The analysis results indicate that the seismic failure mode of the continuously corroded bridge pier varies with the service time, and the plastic hinge has the possibility of transferring from the column end to the bottom of the splash and tidal zone.