Study On The Seismic Responses And Shock Absorption Technique Of Liede Self-anchored Suspension Bridges

In recent years, earthquake disaster frequently occurred in worldwide which brought great damage to the safety of life and property for people. As a bridge of life line engineering, seismic design is an indispensable part in bridge design because of seismic influences on the safety and reliability of the structure. However, from the document that has exited, there is little research on seismic response as well as seismic mitigation and isolation of self-anchored suspension bridge. In this paper, Liede Bridge at Guangzhou, a single-tower self-anchored suspension bridge with the main span of 219m, is an example for the analytic solution of seismic mitigation and isolation and seismic response. The main finished work covers the following aspects:(1) Based on the space finite element theory, the dynamic calculation model of Liede Bridge is established by using the finite element software MIDAS/Civil, the dynamic behavior of the model is performed and the first 10 frequencies and corresponding vibration modes are given. These data is a basis for seismic response analysis.(2) Following the fortifying demand of three-level seismic resistance, under the effect of earthquake probability P1, the seismic response of Liede Bridge is analyzed by the response spectrum method. The internal force, the displacement, and the stress of girder and tower are calculated subjected to longitudinal excitation, lateral excitation, vertical excitation and two kinds of seismic combinational modes which are longitudinal vibration plus vertical vibration and transverse plus vertical seismic excitation. In order to ensure the precision, the CQC (Complete Quadratic Combination) approach is applied.(3) The nonlinear of the structure taken into account, three artificial ground motions generated by proportion method are used as input earthquake to calculate the seismic response of the self-anchored suspension bridge with time history analysis. The response time histories of internal force, displacement and stress of main beam and tower are obtained. The seismic response computed with time history analysis is compared to that computed with response spectrum analysis method, the effects caused by vertical seismic component and structural damping is compared.(4) This paper expounds passive energy dissipation mechanism of viscous damper. Fixing four longitudinal viscous dampers on Liede Bridge and verified the effect of the viscous dampers, finally the sensitivity of the parameters of viscous damper is analyzed.