Running Safety Analysis Of Long-Span Railway Cable-stayed Bridge under Seismic Excitations

In order to study the effect of earthquakes on the safety of high-speed railway running over the long-span cable stayed bridge, based on the dynamic interaction theory of train-railway-bridge, the cable-stayed bridge of the twin towers in Quanzhou bay with the double-span composite beam of (70+70+130+400+130+70+70) m is taken as the engineering background. The train-track-bridge coupling vibration analysis model under earthquake action is established. The self-developed train-track-bridge analysis system program TTBSAS is used to simulate the calculation of one measured seismic wave by relative motion method. The influence of the train speed, ground motion peak acceleration and traveling wave effect on train running safety on the cable stayed bridge of semi-floating system, and get the safe speed threshold when the CRH3 high-speed train passing through the bridge during earthquakes. The results show that the speed, the peak acceleration of ground motion and the traveling wave effect has great influence on the train running safety index on the cable-stayed bridge. The dynamic response of the train-bridge system is larger when the traveling wave speed is 200m/s. The safety threshold of CRH3 high-speed trains under seismic intensity of 7 similar to 9 degrees is 300km/h.