Research On Seismic Response Control For Long-Span Cable Stayed-Bridge

It is well known that the long-span bridge is the important traffic lifeline project, as soon as destroyed in the earthquake, it will cause the enormous economic lose. How to improve the earthquake resistance ability of bridges is always an important subject for research as well as the goal for pursuing. So the security appraisal of the earthquake must be carried on for these projects. Also, it is very important to adopt the effective seismic fortification measures to insure the safety of the structure in earthquake.In the paper, firstly, dynamic analysis model of one cable-stayed bridge is set up, structure dynamic characteristic analysis and seismic response analysis are carried on. The analysis indicates that the cable stayed- bridge produces large displacement under earthquake. Suitable devices should be employed to control the displacement for the seismic safety of the bridge.Then, reduction of seismic response effectiveness of elastic link device is studied in this paper. The rational elastic stiffness K is confirmed through the parameter sensitivity study. This paper also probes into the impact of elastic link device on structure dynamic characteristic.Viscous damper, a damper relevant to velocity, can consume large number of vibration energy without adding any stiffness for the structure. It still permits the deck of the bridge deform freely without any additional internal force when the temperature fluctuation, shrinking and creeping occur. This paper studies reduction of seismic response effectiveness of the nonlinear viscous dampers through non-linear dynamic time history analysis when the damper is installed at different kinds of position. The parameter sensitivity study of each position is carried on to decide the rational damping coefficient C and damping exponentα. Finally, synthetical analysis is carried on to decide which method is better for this bridge.The analysis indicates that both elastic link device and the damper with rational parameters may reduce the seismic displacement significantly, but the method when damper is set at tower and the deck of bridge at the same time at assistant pier and the deck of bridge is better.