Seismic Response Analysis And Vibration Control For Extra-long Span Cable-stayed Bridge

Large span cable system bridge has become the hub of many important transportation routes with powerful leapfrog ability.These important transportation lines are often related to the lifeblood of the national economy. Our country has frequent earthquake occurrences. To keep the safety of l arge-span bridges under seismic action is very important. Up to now, China has construct a number of large-span bridges with more and more flexible structure,larger and larger cycles. The traditional structral seismic analysis methods have been difficult to cope with large span bridges. How to ensure the structural safety of large-span bridges with not too conservative design has become an important issue in the field of large span bridge analysising. In this paper, we have studyed the Sutong Changjiang Road Bridge---1088-meter-span cable-stayed bridge, based on finite element program SAP2000, to analysis its seismic response and find a reasonable measure for vibration control. The main contents are as follows:1. Research on dynamic characteristics of large span bridge. Build the finit e element model to analysis free vibration law according to the eigenvalue theory. And predict structral seismic response with the result of modal.2. Collect data at the bridge site, base on specification to generate artificial seismic waves by trigonometric series method. The linear and nonlinear dynamic time history analysis is carried out with multi-dimensional and multi-angle seismic input. Summarize the law of these bridges’ seismic response.3. Study the impact of the ground motion spatial difference, by dynamic history analysis of long-span cable-stayed bridge considered traveling wave effect. And the contrast the result with the case of uniform excitation to research the impact of traveling wave effect to large span bridge.4. Select reasonable measures to reduct seismic response of large span cable-stayed bridge. In Sutong Bridge, we set several viscous dampers in lognitudinal direction and TMD system in transverse direction. And also we evaluate the vibration-reduction measures by dynamic time-history analysis of the bridge.