Life-Cycle Performance of Concrete Bridges Exposed to Corrosion and Seismic Hazard

The seismic performance of concrete structures should be considered time-variant, since in aggressive environments the corrosion phenomena affect the characteristics of both reinforcing steel bars and concrete matrix during lifetime. Seismic design criteria should therefore account for the environmental hazard, especially if bridges are considered, because of the direct exposure of the structure to the atmosphere. This paper investigates the seismic performance of bridges by considering the interaction between the diffusion process and the corresponding mechanical damage in both deterministic and probabilistic terms. Lifetime moment-curvature analyses are carried out at cross-sectional level of the bridge piers under different scenarios of environmental aggressiveness, accounting for uncertainties involved in corrosion parameters, material properties and structural geometry. Static and dynamic analyses are then performed on a bridge structure to assess how the time-variant seismic performance depends on the environmental exposure. Results show that a bridge designed for the same seismic action could have a different lifetime performance depending on the level of corrosion. This confirms the important role of a life-cycle approach for seismic assessment and design procedures which should be revised to consider both seismic and environmental hazards.