Study on residual lateral drift ratio of RC bridge column with various cumulative damage under quasi-static cyclic loads and earthquake dynamic loads

Abstract

The post-earthquake residual lateral drift ratio of reinforced concrete (RC) bridge columns significantly affected the post-earthquake traffic functionality of the RC bridge. This study investigated the residual lateral drift ratio of RC columns with various cumulative damage under quasi-static cyclic loads and earthquake dynamic loads. To this end, a quasi-static test with multi-turn incremental reciprocating cycles and a one-turn cyclic same peak displacement was conducted to assess static residual displacement of RC columns with various cumulative damage under quasi-static cyclic loads. Test results showed that RC columns with larger cumulative damage exhibited lower unloading stiffness and smaller static residual displacement compared to those with smaller cumulative damage at ultimate displacement. Then, theoretical skeleton curves and unloading rules for RC columns considering deterioration due to cumulative damage were developed. Subsequently, the static residual displacements of RC columns with various cumulative damage levels under different target loading displacements were investigated based on the finite element (FE) model. Further, the dynamic residual lateral drift ratios of RC columns with various cumulative damage levels under earthquake dynamic loads were investigated, and the effect patterns of structural design parameters on residual displacements were analyzed using the incremental dynamics analysis (IDA) method. Results showed that RC columns with larger cumulative damage exhibited larger static residual displacements in the elastic phase and smaller static residual displacements in the plastic phase. The influence laws of cumulative damage of RC columns on dynamic residual displacements were inconsistent: for asymmetric ground motions, nonpulse-like ground motions resulted in larger residual lateral drift ratios, while for symmetric ground motions, near-fault pulse-like ground motions led to greater residual lateral drift ratios.