Research On The Seismic Response Analysis Of Railway Suspension Bridge In Hign-Intensity Earthquake Zone

As a key project in the transportation line, the bridge absolutely plays a significant role throughout either the road traffic lines or railway traffic lines. If the bridge is damaged in the course of a strong earthquake, it may bring about greatly serious casualties as well as enormously economic losses. In addition, the interruption of lifeline will make the disastrous situation worse, and the reconstruction work must be badly obstructed.In the process of rapidly railway expansion and constructing rail infrastructure, the construction of railway suspension bridge is inevitable. The railway suspension bridge in the high-intensity earthquake zone should be long-span and support larger dead and live load. In such case, the further research on earthquake response and anti-seismic design of railway suspension bridge is extremely urgent.Equipped with the finite element software Midas Civil, this thesis aims at firstly building three-dimensional finite element model of a railway suspension bridge, with beam elements, tension-only elements and plate elements, then analyzing the dynamic characteristics of this suspension bridge. By using linear and nonlinear time-history analysis method, the thesis analyzes the seismic response of the railway suspension bridge under four seismic load combinations. The thesis also analyzes the railway suspension bridge with different girder weight by using nonlinear time-history analysis.The research results indicate:(1) The railway suspension bridge has a long natural vibration period, also significantly structural flexibility characteristics.(2) The nonlinear characteristics of suspension bridge obviously affect the seismic response of railway suspension bridge. Therefore, the railway bridge designed by the results of seismic nonlinear time-history analysis should be safer than by results of linear analysis.(3) After adding the vertical seismic force in the combinations of earthquake load, the technical indicators, such as displacements of beam-end and bridge tower top are slightly affected. However, the vertical displacement of mid-span and the axial force at bottom of bridge tower are greatly changed. Thus, the vertical seismic force cannot be ignored.(4) The seismic response of railway suspension bridge is not sensitive to variation of girder weight, the indicators will change in a tendency when girder weight changes, but very slight.