Seismic performance of a GFRP–concrete–steel hollow section segmental column with SMA bars and replaceable ED devices

This paper investigates the seismic behavior of a novel precast segmental bridge column (PSBC). Glass fiber reinforced polymer (GFRP)-concrete-steel hollow section segments were used to construct the column. Hybrid energy dissipation (ED) system consisted of shape memory alloy (SMA) bars and replaceable external ED devices was proposed to increase the ED capacity of the PSBC. The SMA bars have a large deformation capacity, which makes them not easy to be damaged. They were therefore installed inside the column to absorb energy and more importantly to keep the residual displacement small. External ED devices were used to increase the overall ED ability of the PSBC. The external arrangement of the ED devices made it possible and easy for the post-earthquake replacement. A reference PSBC with steel-reinforced precast segments was also constructed and investigated. The test results demonstrated that, compared with the traditional PSBC, the proposed column exhibited appealing seismic performance, including better self-centering capacity, higher post-yield stiffness, and better ED ability. Furthermore, the proposed PSBC experienced minimal concrete damage during the test. One of the external ED devices fractured, however, they could be uninstalled and replaced easily. Numerical models were developed and used to conduct parametric studies. The results demonstrated the feasibility of using the hybrid ED system and the GFRP–concrete–steel​ hollow section segments to improve the performance of the PSBC under seismic loadings.