The Seismic Response Analysis Of Single Tower Cable-stayed Bridge

Long span cable-stayed bridges generally are the key structures of transportation system. Great direct and indirect economic loss will be caused if these bridges getdamaged in an earthquake.Therefore, it is necessary to study and master the seismic response of long span bridges in order to establish reasonable seismic design system and take effective anti-seismic measures. In this thesis, choosing a long span single tower cable-stayed bridge in a highly seismic region of East China, as the example which is a single tower cable-stayed bridge, the seismic responses about this type bridge are investigated as follows:1,This paper establishes bridge space finite element model, compareing the dynamic characteristics of bridge under two different boundary conditions at the tower and pier by model building with the fixed end condition and the pile-soil interaction condition. The calculating results indicate that the pile-soil interaction has effect on the dynamic characteristics of such bridges.2,According to the analysis on proofSafety of Earthquake at the area of Engineering site,which provides acceleration response spectrum curve with 3% exceeding probability in the future 50 years.Inputing the acceleration response spectrum curve along the longitudinal, transverse and multidimensional direction-horizontal combined vertical, the internal force and displacement of the control sections are gained. Compareing the results, the influnce of vertical seismic excitation is not neglected.3,The long span single tower cable-stayed bridges considering geometric nonlinearity, material nonlinearity, boundary elements and other non-linear dampers,when Inputing the acceleration time-history curve with 3% exceeding probability in the future 50 years. This paper analysis and summarizes the results,which show isolation bearing and the damper can improve the structure of the security capabilities in a strong earthquake, when inputing multidimensional direction-horizontal combined vertical time-history curve to the bridge.The conclusions of this paper can be used as the basis of seismic design of such kinds bridge and is useful for directing seismic response analysis of other kinds bridge.