Resilience-based performance and design of SMA/sliding bearing isolation system for highway bridges

• DOI: 10.1007/s10518-021-01220-y
• Publication Date: 2021-09-09T10:04:21Z
• Authors: Yutao Pang; Yixian Sun; Jian Zhong
• Keywords: 0211 other engineering and technologies; 02 engineering and technology

Restrainer-type sliding bearing (RTSB) is a practical seismic isolation system for reducing the excessive displacement of flat sliding bearings under strong earthquakes to ensure the seismic safety of highway bridges. Due to the good corrosion resistance and considerable energy dissipation capability, SMA cables can be used in the RTSB to form the SMA-restrained RTSB to improve its performance. To realize the reliable seismic design of the SMA-restrained RTSB, this paper adopted the seismic resilience-based evaluation method to give the optimum design to minimize the seismic resilience of the bridge system. Firstly, a new index of seismic resilience was defined in the proposed resilience-based methodology to account for the variability of ground intensities. The quantile regression was also proposed to improve the estimation of seismic demand dispersions for seismic fragility analysis. The seismic performance of highway bridges isolated with the SMA-restrained RTSB was compared with different sliding bearings to investigate the effect of slack cables on the seismic performance of the SMA-restrained RTSB. Finally, an extensive parametric study was conducted based on a Gaussian Process Regression (GPR) model together with the uniform design method to investigate the sensitivity of different bearing parameters. The optimal design of the SMA-restrained RTSB bearing was then obtained based on the GPR model and genetic method. It is concluded that the mechanical properties of SMA-restrained RTSB have a significant effect on the seismic resilience of highway bridges. The proposed seismic resilience-based methodology can be adopted to obtain the optimal designs of the SMA-restrained sliding bearings given the target resilience of highway bridges.