Seismic Performance Evaluation of Highway Bridges under Scour and Chloride Ion Corrosion

Cross-river bridges located in seismically active areas are exposed to two major natural hazards, namely earthquakes and flooding. As the scour depth increases, more parts of the bridge substructure will inevitably be exposed to unfavorable conditions such as chloride ion (Cl-) corrosion. To investigate the seismic performance of highway bridges under the action of scour and Cl- corrosion, a spatial finite element dynamic model of a continuous rigid bridge was established and a Cl--accelerated electrochemical corrosion test and quasi-static test were carried out. The results showed that a reasonable scour depth and the combination sub-factors under the joint probability density of scour action and seismic action can be obtained to establish the combined expression of the action effect. Cl- corrosion can cause a reduction in displacement ductility, load-bearing, and energy dissipation capacity, and increase inequivalent viscous damping coefficient of the columns. Seismic damage of the columns grows linearly to twice the ultimate displacement under Cl- corrosion, which becomes more significant with the increase of the reinforcement ratio.