Effect of Seismic Retrofitting on the Behavior of RC Bridge Columns Subjected to Main Shock-Aftershock Sequences

Experiences from previous earthquakes around the world have shown that a structure may face seismic sequences in a short period of time. Since there is not enough time for strengthening the structures during the time span between the earthquakes, the structures experience a level of degradation. Previous codes didn't provide the requirements on seismic sequences effects on the bridges. Recently, some researchers studied the effect of multiple earthquakes on nonlinear behavior of RC columns. Many of the previous studies used artificial sequences to investigate the behavior RC bridge columns. The other important thing needing more attention is the effect of FRP confinement on the increase of structural performance. Therefore in this study nonlinear behavior of the RC piers of a bridge under as-recorded multiple earthquakes and for different FRP confinement levels are investigated. Results of this study indicate that considering a full confinement in piers may slightly improve the structural performance. Findings also show that the effect of the damage from the main shock is negligible for a long span bridge.