Abstract:In order to study the influence of traveling wave effect in spatial ground shaking on the dynamic response of a self-anchored suspension bridge, taking a long-span suspension bridge as the study background, a seismic design response spectrum meeting the site characteristics of the suspension bridge site is determined, and is used as the target spectrum. Based on the stochastic vibration theory, the target response spectrum is converted to an equivalent acceleration time history curve, which is used as the ground motion input for the seismic analysis of long-span suspension bridge. According to the dispersion of the apparent velocity of the seismic wave, 400 m/s, 800 m/s, 1200 m/s and 1 600 m/s are selected to consider the influence of traveling wave effect on the dynamic response of the long-span suspension bridge. The results show that when the apparent wave velocity is less than 1 200 m/s, the bottom shearing force of the bridge pylon increases with the increase of the apparent wave velocity. When the apparent wave velocity is greater than 1 200 m/s, the bottom shearing force of Pylon 1 decreases with the increase of the apparent wave velocity, while the bottom shearing force of Pylon 2 increases. When considering the traveling wave effect, the bending moment of the bridge pylon fluctuates up and down with the increase of the apparent wave velocity. However, compared to the consistent excitation case, the bending moment response values at the bottom of Pylon 1 fluctuate up and down at the bending moment values obtained in the case of consistent excitation, and the bending moment at the bottom of Pylon 2 is always smaller than that of consistent excitation. The displacement at the top of the bridge pylon is greatly influenced by the traveling wave effect, and the maximum displacement response of the pylon top is two times that of the consistent excitation. It is very necessary to consider the traveling wave effect in the seismic design of long-span suspension bridges.
