Seismic Assessment of Reinforced Concrete Bridge Under Chloride-Induced Corrosion

摘要

Chloride-induced corrosion continues to the main cause of deterioration of concrete structures in the marine areas. To introduce the high rate of corrosion in Persian Gulf area, the axial load-carrying capacity of reinforced concrete columns, which have been exposed to the real corrosive condition of this area about 1.5 years, is measured. Then, a new framework for long-term seismic evaluation of existing corroded reinforced concrete bridge in this area is proposed. Calculation of corrosion initiation time, development of material model considering effects of corrosion, moment-curvature analysis of bridge columns, determination of plastic hinge characteristics, and pushover analysis in longitudinal and transverse directions of the bridge are the main steps of proposed framework. Effects of corrosion include the degradation of cover and core concrete, steel bar, and bonding between concrete and steel bar. By comparing the obtained seismic capacity of bridge at specific time points in bridge service life, effect of corrosion on the long-term seismic performance of bridge is determined. On the basis of analysis results, due to ensuring the long-term seismic performance of seismically designed reinforced concrete bridge in the marine area after 90 years of service, it is suggested in this paper that the design base shear should be increased by 12.5%.