Superelastic Conical Friction Pendulum Isolator for Seismic Isolation of Bridges under Near-Fault Ground Motions

Abstract

To improve the seismic performance of bridges, this study develops a novel superelastic conical friction pendulum isolator (SCFPI) by incorporating an improved conical friction pendulum isolator (CFPI) with shape memory alloy (SMA). The flat sliding function designed for the improved conical friction pendulum isolator is to enhance the adaptability under service loadings. The analytical model of the novel SCFPI is derived and the numerical model is developed within the OpenSees platform to investigate the hysteretic behavior under cyclic loadings. A cost-effective design method is proposed to design the SCFPI system for example bridges. The response mitigation efficacy of the novel SCFPI system is investigated using the optimum design parameters under near-fault ground motions. Several case studies are conducted to demonstrate the effectiveness of the novel SCFPI system and cost-effective design method. Results indicate that the cost-effective design method is particularly effective for parameter optimization of the novel SCFPI, which achieves effective mitigation for the displacement responses of the isolator and superstructure and also effectively controls the seismic force increment in piers. Case studies indicate the reliable re-centering capacity and mitigation efficacy of the SCFPI system for bridges under near-fault ground motions. The findings of this study contribute to upgrading structural resilience and promoting seismic applications as a reliable technical guidance.