Experimental investigation of seismic behavior of RC double-column medium-height bents with rocking link beams

For reinforced concrete (RC) double-column medium-height bents (DCM bents) with link beams, RC link beam-column joints are susceptible to damage under strong earthquakes, which may cause significant inconveniences for maintenance and repair following earthquakes of the bridge structure. To improve the seismic performance and facilitate post-earthquake repair of DCM bents, rocking link beams (RLBs) were applied in double-column bents to replace traditional cast-in-place link beams based on the merits of rocking structure with self-centering capacity and damage controllability in this study. The mechanical behavior and force analysis of the DCM bent with rocking link beams were introduced. Then, the hysteretic behavior of rocking link beams based on steel angles and post-tensioned (PT) tendons was investigated through experimentation, and the test results showed that the RLB exhibits a flag-shaped hysteretic behavior with smaller residual deformation and greater bearing capacity compared with that of the RLB without PT tendons. Subsequently, the quasi-static cyclic loading tests of the DCM bent with the RLBs specimen were carried out, and a DCM bent and a DCM bent with RC link beams were also tested for comparison. The experimental results show that the DCM bent with RLBs suffered the least damage compared with the DCM bent and DCM bent with RC link beams, and there was no obvious damage in the beam-column connection joints. In particular, the DCM bent with RLBs exhibited excellent hysteresis behavior with a large carrying capacity, stable energy dissipation, and no significant deterioration in strength.