Energy response analysis and seismic isolation strategy optimization of high-speed railway bridge-track system under earthquake action

The formulation and optimization of a seismic isolation strategy is crucial for improving the seismic performance of high-speed railway bridge-track systems (HSRBTS) under earthquake action. In line with this proposition, therefore, this paper studies the seismic isolation strategy optimization of HSRBTS based on an energy response analysis. More specifically, the energy dissipation distribution of common and isolation HSRBTS under different earthquake strength levels is analyzed. The results show that when the peak ground acceleration (PGA) is greater than 0.3g, the seismic input energy of isolation HSRBTS is smaller than common HSRBTS. With the increase of PGA, the total proportion of hysteretic energy dissipation increases while the proportion of damping energy dissipation decreases in common HSRBTS, with the opposite being observed in isolation HSRBTS. Bearings and piers are the main hysteretic energy dissipation components for HSRBTS. Thus, in view of the energy dissipation requirements and structural characteristics of HSRBTS, this paper proposes an energy-based optimization principle. Under the existing isolation HSRBTS, the seismic isolation strategy is optimized to achieve a uniform distribution in hysteretic energy dissipation, while the effectiveness of the optimized seismic isolation strategy is submitted to further verification.