Seismic assessment of corroded concrete bridges using incremental modal pushover analysis

An efficient yet accurate procedure was developed for the seismic assessment of reinforced concrete (RC) bridges subject to chloride-induced corrosion. The procedure involves using incremental modal pushover analysis to assess corroded bridges as an alternative and less computationally demanding approach to non-linear dynamic analysis. A multi-physics finite-element analysis is performed to evaluate the effects of chloride-induced corrosion on bridge columns. In doing so, chloride ingress in concrete is numerically simulated as a diffusion process by considering the effects of temperature, humidity, corrosion-induced cover cracking and concrete aging. The estimated chloride concentration is then employed to evaluate the corrosion current density, from which the effects of corrosion on reinforcement, cracked cover concrete, confinement and plastic hinge length can be determined for subsequent non-linear static analysis. A case study of a typical bridge structure is presented. The proposed procedure can be used to assess the seismic performance of irregular RC bridges exposed to severe corrosive environments.