Experimental study on GFRP-steel double-skin rubber concrete composite piers under mixed loading

Abstract

To address the issues related to the insufficient compressive and shear strength of rubberized concrete and to enhance the deformation capacity and longevity of composite piers, a novel approach involving the confinement of rubberized concrete with glass fiber-reinforced polymer (GFRP) tube and steel tube has been proposed. This method aims to create a GFRP-steel double-skin rubberized concrete composite pier. Pseudo-dynamic and quasi-static tests were conducted on the composite pier to assess its seismic response and residual seismic performance. The study investigated the failure mode, hysteretic characteristics, ductility, energy dissipation, stiffness, and self-centering capability of composite piers. Additionally, a correction coefficient for the equivalent plastic hinge length was proposed. The results indicate that the specimen maintains its elastic state when subjected to frequent seismic events. However, when subjected to infrequent seismic events, the glass fiber layer may fracture, leading to the development of white stripes, while the steel tube experiences yielding, transitioning into a plastic state. The shock absorption and toughness of rubberized concrete were effectively utilized when subjected to horizontal low cyclic loading, thereby mitigating the appearance of more pronounced damage in seismic-damaged specimens. The hysteretic curve was complete, demonstrating a significant energy dissipation capacity. This confirmation indicates that the composite pier can be a viable solution for sea-crossing bridges and complex environments.