Experimental Study on an Innovative Double-Limb-Thin-Wall Bridge Pier with Longitudinal Replaceable Connecting Beams

Abstract

Replaceable energy dissipation elements can reduce damage to main structures and improve seismic resistance of bridge structures. However, in existing studies, replaceable energy dissipation elements are mainly arranged in the transverse direction of the bridge structure, while little attention is given to the longitudinal direction of the bridge, which also suffers from serious damage under earthquakes. This paper proposes an innovative double-limb-thin-wall (DLTW) bridge pier, which consists of two thin-limb-wall columns in the longitudinal direction of the bridge and replaceable steel connecting beams (RSCBs) between them. Quasistatic tests of the proposed innovative DLTW pier with RSCBs (DLTW-RSCBs), a conventional DLTW pier, and a DLTW pier with RC connecting beams (DLTW-RCCBs) were conducted to investigate the longitudinal seismic performance of the innovative bridge pier. The test results demonstrate that the use of connecting beams (CBs) can improve the lateral bearing capacity and cumulative dissipated energy of the DLTW pier, while the improved amplitudes are more significant for the DLTW-RSCB specimen, about 21.6% and 13.4%, respectively. Moreover, due to the protection of the CBs, the DLTW-RCCBs and DLTW-RSCBs have lower damage and residual drift ratios than the DLTW-NBs before the failure of the CBs. However, the differences between these three piers gradually disappear with the failure of the CBs, and the piers are finally destroyed as a result of the failure modes of buckling and low-cycle fatigue fracture of the longitudinal bars at the column bottom. Moreover, RSCBs can still be rapidly repaired after damage failure of the DLTW-RSCB specimen. Therefore, setting replaceable steel beams between DLTW piers can effectively improve seismic performance and reduce seismic damage and repair costs of DLTW bridge piers under earthquake loading, which are valuable for sustainability during the service stage. The outcomes of this work can serve as a reference for further development of structural forms for the innovated pier.