Research On Seismic Performance Of Longspan Single Tower Self-anchored Suspension Bridge

The self-anchored suspension bridge eliminates the huge anchorage,and the main cable is directly anchored on the stiffening beam.However,the huge vertical component force of the anchorage point of the main cable will be directly transferred to the stiffening beam.In some special topographic conditions,the above mentioned way to balance the vertical force of the main cable with the weight of the besm is not suitable.At this point,the stiffening beam and pier can be consolidated,and part of the vertical force of the main cable is borne by the foundation.This method can effectively reduce the dead weight and cost of the girder,but there are still some aseismic problems to be studied.In this paper,pier-beam consolidation method is adopted at one anchorage point of main cable in the support project,and piers and beams at other piers are connected by bear.As this bridge is located in highly seismic area,the dynamic characteristics of the structure and the distribution of horizontal seismic force have changed greatly after the piers and beams are consolidated.Therefore the aseismic design has become a key point of the bridge.With the support project,this paper focuses on the following aspects:(1).This paper firstly analyzes the influence of the change of the pier-beam connection on the dynamic characteristics of the self-anchored suspension bridge.(2).After the pier and beam is consolidated,the seismic response of the structure changes with the change of the dynamic characteristics of the structure.The distribution of horizontal seismic force between different tower piers becomes quite complex,and the aseismic design of the consolidation pier becomes emphasis.In this paper,the elasticplastic finite meta-dynamic analysis model of pier-beam consolidation and pier-beam non-consolidation is established based on the support project,and the nonlinear time seismic response of the bridge before and after the change of pier-beam connection mode is analyzed.Furthermore,this paper also studies the influence of the change of pier-beam connection mode on the seismic response of the bridge,and discusses the influence of the change of pier beam connection on the dynamic characteristics of the bridge.And the seismic performance of the self-anchored suspension bridge under pier-beam consolidation system and pier-beam movable support system was comprehensively evaluated.(3).In linear circumstance,using multiple seismic waves with the same response spectrum to analyze the time of structural seismic response,the maximum of structural seismic time response obtained by different waves is basically the same,However,in nonlinear circumstance,the maximum of seismic time response of structures obtained by different waves is quite different,which has been studied by researchers through the analysis of non-linear seismic time response,but they have mainly studied the bilinear circumstance in non-linear circumstance.With the support project,the author selects several seismic waves with the same response spectrum,using more complex nonlinear hysteretic curves By analyzing the nonlinear time,the author obtains the seismic response of the bridge under different seismic waves,studies the discreteness of the nonlinear response of seismic response,and analyzes the causes of the discreteness.