| As one important part of lifeline, the damage of the bridge during the earthquake will bring great difficulties to earthquake relief work and post-disaster reconstruction. Therefore, it is important to ensure the safety of bridges. XingHai Bay bridge is a big span double steel truss uplift of self-anchored suspension bridge. As a large-span suspension bridge with the main span of 460 m, its significance is understood without explanation. Therefore, the research on the seismic responses and shock absorbtion technique is a vital necessity.As the study background, the development status of large-span bridges and the structure damage of bridges caused by major earthquakes in history were briefly reviewed. Then, the existing studies on analysis methods of seismic responses and measures of shock absorption, as the theory basis, were introcuced.Space finite element dynamic model was established with the finite element analyse software ANSYS, and dynamic characteristics were analysed at the same time, the comparison of the effects of whether setting up the central buckle on XingHai Bay bridge dynamic characteristics was made as well. The first 300 natural frequencies and its according mode shape were obtained through the analysis of vibration characteristics. Thereby, the response spectrum analysis was performed to assess the seismic response. The seismic response of XingHai Bay bridge was primarily understood.By making use of four natural seismic waves chosen, seismic response analysis was performed with dynamic time-history analysis from three perspectives. During the vertical earthquake input, seismic response analysis was analysed under linear consistent input, nonlinear consistent input and traveling wave input, and the influce rule was explored as well. At the same time, it was compared with response spectrum method, which verified the statistical rule abd accuracy of time-history analysus results.From the analysis of response spectrum and schedules of XingHai Bay bridge, it could be seen that the structure vibration in longitudinal vertical, horizontal and vertical was obvious under the seismic action. Therefore, this paper analysed the effects of setting up the central buckle on XingHai Bay bridge and the impacts of viscosity damper and tuned mass damper on shock absorption of XingHaiwan bridge. Here were some meaningful conclusions. The longitudinal vertical vibration of stiffening girder was restrained effectively by setting up the central buckle, at the price of increasing the internal force responses of other parts. The displacement of stiffening girder was restrained effectively and the structure stress was improved properly by introducing viscous damper. Therefore, shock absorption and structural components protection were realized. TMD restrained the horizontal and vertical vibration of stiffening girder under the effects of earthquake effectively. Compared to single TMD, MTMD brought better effects of shock absorption and also reduced the qualities of TMD, which was in favor of the installment and usage of engineering. |
