Seismic Response Analysis Of Long-span Cable-stayed Bridge Under Multi-support Excitation

The Long-span cable-stayed Bridge is applied very broad in modern society, it is a cable-supported system has three basic components:main tower, beams and cables. This bridge is a cable transmission system load beam to the tower, and its flexible is better than normal bridges, therefore, the dynamic characteristics are very different with general bridges, so it is necessary to study and explore. In this paper, the background of the engineering analysis is a four-span cable-stayed Pylon build to study the dynamic response of the earthquake, and these provide information for seismic design and construction of building and testing reinforcement. The work and conclusions is following of the article:First collected some seismic data, including the classification of earthquakes, seismic characteristics and hazards; then analysis the characteristics of the Long-span cable-stayed bridge for references of the design of such bridges, at the same time the key issues are pointed out-the dynamic problem of Long-span cable-stayed bridge. Finally takes into account the development of the bridge and the design specification improvements, and focus on the seismic design of three ways:response spectrum, time history analysis and random vibration theory.Establishing a finite element model with MIDAS according to a four-span cable-stayed three towers bridge, then analysis the conditions on the modal of considering pile-soil-structure interaction and does not consider pile-soil-structure interaction, so some conclusions are drawn:Of the two conditions, the frequency of the model B is less than the frequency of model A; in low mode, vibration characteristics is same of Model A and Model B; considering the pile-soil-structure interaction effects on structures mainly appear the advanced stage and so on.Through a horizontal design acceleration response spectrum curve and still at the two conditions, analysis the simulation data, the effect of the interaction on the impact of long-span cable-stayed bridge is limited, especially for axial force and displacement.Non-uniform excitation of the bridge. More incentive makes beam's cross-section and the pier top displacement increase of the bridge, the shearing stress on the high pier and short pier is obvious, and the impact on the pier of the law is not obvious.Span cable-stayed bridge on the seismic response of a time history analysis. through the incentive and motivation comparison, when considering the earthquake excitation, the internal force, deflection is increased of the bridge. Traveling wave effect must be considered when designs this series, traveling wave's effect is different following the inputting direction's differ of vibration.Reviewing the work of the article and put forward some proposal comments based on research.