Seismic Response Analysis Of Self-anchored Suspension Bridge With Single-pillar Tower And Space Cable

Compared with the traditional self-anchored suspension bridges,self-anchored suspension bridges with spatial cables and single-column tower are a new type system.Their main cables are distributed in spatial space and hangers are inclined in the horizontal direction and the inclinations are different from each other,which make them have different dynamic responses from ordinary self-anchored suspension bridges.Therefore,it is necessary to research this new kind of structure.Based on the engineering background of Nanjing Jiangxinzhou bridge,this paper researched the dynamic characteristics and seismic responses of self-anchored suspension bridge with spatial cable and single-column tower.Firstly,this paper established the finite element model of Jiangxinzhou bridge with the software of Midas/civil,and elaborated the method of determining the reasonable finished state of self-anchored suspension bridge with spatial cables.The reasonable finished state of structure was determined and verified under load.Secondly,using the subspace iteration method,this paper analyzed the dynamic characteristics and changes of structural parameters of self-anchored suspension bridge with spatial cable and single-column tower and the ground-anchored one with the same structural parameters.Moreover,the influence of pile-soil interaction on dynamic characteristics of Jiangxinzhou bridge is discussed.Lastly,based on seismic response spectrum and time-history analysis methods,the seismic responses of self-anchored suspension bridge with spatial cables and single-column tower are researched,and the influence of pile-soil interaction on seismic response is further researched.The results show that compared with the ground-anchored suspension bridge,the self-anchored system can effectively improve the longitudinal rigidity of structure.The pile-soil interaction lowers the whole rigidity of structure and greatly influences the dynamic characteristics of structure.The horizontal vibration is basically not coupled with the longitudinal vibration and vertical vibration.The vertical seismic effect has much influence on the stress of hangers.When ignoring the pile-soil interaction,the results of seismic response at the bottom of tower are comparatively conservative,and conversely,the vertical moment at the middle of the girder and the displacement of structure are shortly estimated.Therefore,the seismic response cannot represent the most unfavorable situation and it is not always advantageous to seismic design when ignoring the pile-soil interaction.It is necessary to consider the pile-soil interaction when accurately researching the structural seismic response.