Experimental investigation on the seismic behavior of RC double-column medium-height bents retrofitted with SCEB-Us

Abstract

Two columns of RC double-column medium-height bents (DCMBs) are normally connected by link beams to enhance the lateral stability. Serious damage and/or large residual displacement were repeatedly observed in the DCMBs after major earthquakes, which may make the bridges lose traffic functionality or even be demolished and rebuilt. To enhance the seismic performance of bridge structures with DCMB with link beams, the self-centering energy dissipation braces (SCEBs) were applied to the DCMB in the “K”-shaped arrangement scenario to replace the traditional link beams in this study. To this end, the design philosophies of the SCEBs in the DCMB were first developed based on the configuration and force analysis of the DCMB with SCEBs. Then, 1:4 scaled RC DCMB and DCMB with link beams specimens were designed. Based on the design philosophies and the hysteretic performance of the DCMB, a novel SCEB with U-shaped steel plates (SCEB-U) was developed and tested, and the test results showed that the SCEB-U exhibited a typical flag-shaped hysteretic behavior with great deformation capacity. Subsequently, the quasi-static cyclic loading test of the DCMB with SCEBs specimen was carried out, and a DCMB with link beams and a DCMB with energy dissipation braces (EDBs) with U-shaped steel plates (DCMB with EDB-Us) were also tested for comparison. The experimental results showed that the DCMBs with braces suffered the least damage compared with the DCMB with link beams, and there was no obvious damage in the column-brace connection regions. The DCMB with SCEB-Us exhibited excellent flag-type hysteresis behavior with large carrying capacity, stable energy dissipation, and satisfactory self-centering ability.