Seismic Performance of Self-Centering Bridge Piers with Rocking Mechanical Hinges

Abstract

A rocking column has excellent earthquake resistance and post-earthquake recovery capacity. However, concrete spalling or crushing easily occur at the rocking interface due to local high compression stress. In this paper, a rocking mechanical hinge (RMH) is proposed that can minimize the local damage, as well as being able to improve the construction rate of bridge piers. The RMH uses post-tensioned tendons to provide recentering capacity and oval steel dissipaters to dissipate energy. Simplified analytical equations are developed to analyze the hysteretic behavior of the RMH column. Based on the developed simplified analytical equations, the initial post-tensioned (PT) axial load ratio, the PT area ratio, the eccentricity of the bearing plate, and the energy dissipater ratio are parametrically studied, and the recommendation values of key parameters are identified accordingly. Furthermore, nonlinear time history analyses are conducted to investigate the seismic performance of the RMH column, compared with the conventional reinforced-concrete (RC) column and the conventional rocking column. Results show that the RMH column has superior seismic performance, with negligible residual displacement compared with the conventional RC column, and sustains minimized local damage compared with the conventional rocking column.