Experimental Study on the Seismic Performance of Self-Centering Braced Double-Column Rocking Bent

Abstract

The self-centering braced double-column rocking bent (SBR bent) consisting of a double-column rocking bent and two replaceable braces in a chevron arrangement scenario has been developed to enhance the seismic resilience of bridge structures. This paper aims to experimentally investigate the seismic performance of the SBR bent with energy dissipation braces (EDBs) and the self-centering energy dissipation braces (SCEBs). To this end, first, the design criteria of the SBR bent were developed, and a simplified analytical model was established to predict the force-displacement relationship of the SBR bent. Subsequently, in order to meet the large deformation capacity of the rocking bent, U-plate energy dissipation braces (as U-EDBs) and self-centering combined disc spring U-plate braces (as U-SCEB) acting as replaceable braces were developed and tested to investigate their hysteretic behavior. The experiments on two 1:3 scaled SBR bents with the two types of replaceable braces (i.e., U-EDBs and U-SCEBs) subjected to quasi-static loading protocols, were then carried out to investigate their seismic performance. For comparison, a cast-in-place Reinforced concrete (RC) bent and a self-centering rocking bent without brace (SR bent) were also designed and tested. The results indicated that the self-centering combined disc spring U-plate brace exhibits a typical flag-shaped curve, in particular, has a large deformation capacity. Furthermore, SBR bent featured with prominent seismic performance in terms of large load-carrying capacity, excellent self-centering capability and stable energy dissipation ability, minor or no physical damage. Moreover, the external braces can be easily replaced if they are damaged after a severe earthquake.