Hysteretic behavior degeneration mechanism and damage evaluation of self-centering bridge pier system

Abstract

Damage often occurs in the contact segment of self-centering (SC) bridge pier systems and significantly affects their hysteretic behavior under cyclic loading or seismic excitations. To quantify the degree of decline of the mechanical indices in the damaged SC bridge pier system, this study investigated the degeneration mechanism of the SC bridge pier system and its damage evaluation method. First, two damage modes, the resilient damage (RD) and brittle damage (BD) modes, are innovatively defined. Subsequently, the backward movement mechanism of the rotation point in the SC bridge pier system was investigated in detail, and the corresponding degradation mechanism of hysteretic behavior was specified in terms of experimental observation and mechanical analysis. Then, the application of hysteretic degradation mechanism was presented, and its correctness was verified using experimental data. Finally, a novel damage index (DI) specific to the SC bridge pier system, which can reasonably reflect key mechanical properties such as stiffness, yield carrying capacity, carrying capacity, and residual drift, is proposed and compared with existing DIs in terms of principle and evaluation effects. The results confirm that the proposed DI model can accurately evaluate the damage state of the SC bridge pier system.