Analysis of rail-bridge interaction of high-speed railway suspension bridge under near-fault pulse-type earthquakes

Due to the limitations of railway route selection, some high-speed railways are inevitably built near or across fault zones. To study the distribution of rail-bridge interaction under different load history states of suspension bridges under three types of near-fault pulse-type earthquakes, this paper takes China's longest high-speed railway suspension bridge—Wufengshan Yangtze River Bridge as the background and establishes a spatial model of rail-bridge interaction of suspension bridge. The results show that: under the constant load state, the distribution of additional force under three types of pulse-type earthquakes are generally consistent, pulse-type earthquakes produce more significant responses than non-pulse-type earthquakes, with fling-step pulse being the largest, it is advised to specifically consider the influence of the fling-step pulse in the calculation. Under the initial condition of the main beam temperature loading history, all rail-bridge additional forces increase significantly, particularly affecting the steel rail system. The value of the rail-bridge interaction additional force under the near-fault earthquake in the initial state of the suspension bridge when the train deflection load is loaded from the tower to the mid-span is more significant and particularly unfavorable. The initial effect of the braking load will weaken the effect of the deflection load loading history. The results of the study indicate the effect of the initial state of suspension bridges is an important factor influencing the rail-bridge interaction under near-fault pulse-type earthquakes, which needs to be considered in future seismic design.