An improved interlayer area damage model for seismic damage assessment of a high-speed railway long-span arch bridge-track system

The seismic damage of the interlayer continuous components in high-speed railway (HSR) bridges has not been effectively evaluated. This paper presents an improved interlayer area damage model (IADM) that includes two damage indices, the maximum IAD region length and the mean IAD region length. Due to the lower computational efficiency of the HSR bridge model and IADM, this study proposes the use of the Markov Chain Monte Carlo (MCMC) method for random sampling of the response sample of IAD index, in order to obtain response estimations for the IAD indices. First, IAD response samples of different sizes are generated using MCMC simulation. Then, the upper bound values of response samples are calculated. Finally, polynomial fitting is performed on multiple upper bound values. A case study on an HSR long-span steel truss arch bridge-track system (HSRDAB) was carried out. A refined numerical model of the HSRDAB was established. Ground motion (GM) suites were selected for the near-fault hanging wall (HW) and foot wall (FW). The response estimations of the IAD indices under both HW and FW were calculated respectively. According to the findings, the response estimation of the IAD index can be used as an effective evaluation of the seismic damage of the interlayer continuous components. The realization of this process through MCMC effectively enhances computational efficiency. The HW effect has a maximum impact of 2.96 % on the damage of the CA mortar layer when using the mean IAD region length as the damage index.