Seismic Response and Fragility of Deteriorated Reinforced Concrete Bridges

One of the greatest challenges in the United States today is overcoming the deterioration of an aging infrastructure system. In particular, the highway/bridge infrastructure system has traditionally been neglected of maintenance and repair. One of the most concerning degrading mechanisms in the bridge infrastructure is corrosion, and it is compounded by the fact that much of the older infrastructure is not consistent with current seismic code requirements. The research presented here determines the effects of corrosion on the seismic response of a typical reinforced concrete bridge designed according to recent standards, predominantly governed by flexural deformations, and based on realistic lifetime deteriorations in strength due to the reduction in cross-sectional area of the reinforcement and in stiffness due to concrete cover spalling. The findings of the research, given the noted modeling assumptions, are that the losses in strength and stiffness only marginally influence the seismic fragility of the selected bridge.