The Seismic Respond Analysis And Earthquake-reduction Design Of Large-span Cable-stayed Bridge

In the traffic and transportation engineering, large span bridges play a key role and its investment is large.It plays the decisive role in the development of the national economy. If the bridge is destroyed in the earthquake, it will bring great loss to the economy.On the other hand, it would affect the disaster relief and reconstruction work. Because of this, how to improve the cable-stayed bridge’s anti-seismic and damping capacity is classified as a important research direction. When the earthquake occurs, in order to make the long span cable-stayed bridge has enough security, the effective anti-seismic measures must be taken and its social significance and economic significance will also be increased accordingly.When the large span cable-stayed bridge is under damping anti-seismic design, with the effect of seismic force, it is better make the displacement of the cable-stayed bridge and the internal force of main components as small as possible. Under normal circumstances, these two aspects are often contradictory. If making the displacement control as the goal, this force will be increased.The paper takes Huaian bridge as the research background and three different models were built with the help of bridge software Midas.Three models are a cable-stayed bridge model with viscous dampers,a cable-stayed bridge model with horizontal cable damping and a cable-stayed bridge without any measures of damping vibration. The three models has been carried on the dynamic(seismic force) analysis.Through the time history analysis, the damping effect of damper and elastic cable and reasonable design parameters were obtained( reasonable damping coefficient of damper and elastic reasonable elastic stiffness of elastic cable).Analysis shows that,no matter using elastic cable damper or viscous damper damping, under function of earthquake,as long as the choice of parameters is in a reasonable range, the displacement of structure can be controlled well specially for the longitudinal displacement of the bridge.The internal force response will also be reduced in the main bridge. After the comprehensive analysis of three different models, setting the viscous damper in cable-stayed bridge is the best scheme of damping seismic. This scheme not only meets the seismic design specification requirements, but also improve the ability of cable-stayed bridge’s material durability and the ability of structure’s seismic aspects. The study can also provide a reasonable reference in different large span bridge in seismic design.Analysis shows that,no matter using elastic cable damper or viscous damper damping, as long as the choice of parameters is in a reasonable range,the displacement of structure can be controlled well specially for the longitudinal displacement of the bridge.The internal force response will also be reduced in the main bridge. After the comprehensive analysis of three different models, setting the viscous damper in cable-stayed bridge is the best scheme of damping seismic. This scheme not only meets the seismic design specification requirements, but also improve the ability of cable-stayed bridge’s material durability and the ability of structure’s seismic aspects. The study can also provide a reasonable reference in other kinds of bridges in seismic design.