Numerical Investigation and Factorial Analysis of Residual Displacement in Rocking Self-Centering Bridge Columns Under Cyclic Loading

Well-designed rocking self-centering (RSC) columns are capable of achieving small residual displacement. However, quantitative assessments of residual displacement mechanisms in RSC columns remain understudied. The residual displacement is the product of the struggle between the self-centering (SC) capacity and the energy dissipation (ED) capacity. In this study, an SC factor and an ED parameter were defined to reflect the SC and ED capacity of the RSC column, respectively. The hysteretic behavior of an RSC pier under quasi-static load was studied. Based on the finite element model, the factorial analysis of two types of RSC piers was carried out, and the influence of eight common design parameters on the SC factor and ED parameters was discussed. Parametric analysis was performed to investigate the effect of the SC factor and the ED parameter with an increase in maximum displacement. According to the results of the parametric analysis, the effect of the SC factor and the ED parameter on the distribution of the residual displacement was statistically researched. A simplified formula was proposed to calculate the upper limit of the residual displacement. Furthermore, a set of predictive regression formulas was established to estimate the actual residual displacement. These regression formulas have an applicable condition that the ED parameter should be larger than 0.75. When the ED parameter is less than 0.75, the residual displacement is approximately zero. The hysteretic performance of an RSC pier is mainly determined by a single-factor effect, and the residual displacement distribution under a quasi-static load is mainly controlled by the SC factor and ED parameter.