Time-Dependent Reliability and Redundancy of Corroded Prestressed Concrete Bridges at Material, Component, and System Levels

Due to structural deterioration, the performance of concrete bridges degrades with time and may result in catastrophic failure events, especially for nonredundant structures. This paper develops a methodology for assessing time-variant reliability and redundancy of multigirder prestressed concrete bridges at material, component, and system levels. Nonlinear analysis was performed to obtain the constitutive relationship of reinforced sections and girder components in which the adverse effects of reinforcement corrosion on structural capacity and ductility are considered. Subsequently, the nonlinear finite-element analysis was conducted to capture the time-dependent probabilistic resistance of the bridge system, considering different failure criteria (e.g., serviceability and ultimate limit states). Given the component- and system-level performance indicator, structural capacity-, reliability- and risk-informed redundancy was assessed. The feasibility and capability of the proposed approach were illustrated using an existing prestressed concrete bridge. The results demonstrate that the integrated damage mechanism between different levels has a significant effect on the structural ultimate capacity, reliability, and redundancy of corroded structures.