Experimental investigation on seismic performance of self-centering railway bridge piers with replaceable sacrificial components

Conventional self-centering (SC) bridge piers minimize structural damage and facilitate rapid post-earthquake recovery. However, numerous quasi-static tests have shown that damage to auxiliary devices and the rocking interface can cause a significant increase in the residual displacement of SC piers. This study proposes a novel SC bridge pier equipped with sacrificial components (SSC) to mitigate such damage. A spread foundation is introduced at the base of the SSC pier, and grooved glass fiber–reinforced polymer (GFRP) elements serve as sacrificial components connecting the pier to the footing, enhancing initial lateral stiffness under service loads without compromising rocking isolation during strong earthquakes. Two SSC pier models with different sacrificial component diameters, one SC pier model, and one conventional base-fixed ductile (DC) pier model were designed and fabricated. Quasi-static tests were conducted to investigate the working mechanisms and failure modes of the sacrificial components, interfacial damage, residual displacements and hysteretic responses of the SSC piers. The results indicate that the sacrificial components effectively enhance the lateral stiffness and load-carrying capacity of the SC pier without exacerbating rocking interface damage. The failure of sacrificial components successfully facilitated the rocking isolation and post-earthquake self-centering of the pier. While the DC pier experienced concrete cover spalling at a drift ratio of 3.2%, reinforcement strains in the SSC pier remained much lower, keeping the pier intact. The SSC pier also exhibited minimal residual displacements, and the slight damage at the rocking interface did not compromise its serviceability, indicating highly promising prospects for engineering applications.