Seismic Response And Isolation Performance Of Ridge Bridge

With the development of our country’s economy and technology,urban construction is accelerating and urban traffic is becoming increasingly perfect.As an indispensable part of urban transportation,elevated bridges have developed rapidly.The bridge of the spine is connected to a pier by a ridge beam.After the rib beam is placed on the ridge beam,the bridge panel is cast on it.The spine beam has the characteristics of improving the clearance under the bridge,saving material,and flexible arrangement of piers.Since the seismic performance is a problem that must be considered in the design of the bridge,we must make necessary research for the seismic performance of the bridge of the bridge.For the study of the seismic performance of bridges,we start from two aspects,namely the impact of bridge pier height and geological conditions on the dynamic effect of the bridge structure,and then study the change of the dynamic response of the structure under the action of seismic forces when the above two factors are changed.Beam bridge structure design provides theoretical basis and reference significance.In this paper,a bridge model is established by the theoretical analysis and simulation of the finite element software Midas civil,and the seismic response of the main section of the bridge is studied under seismic load.The main conclusions are as follows:1.When the height of bridge pier bridge increases,the natural vibration frequency of the bridge decreases,indicating that the structural rigidity decreases.The first two main modes of the structure do not change as the pier height increases.When the proportion coefficient m of the foundation soil of the structure becomes larger,the natural vibration frequency of the structure becomes larger,which means that the overall stiffness of the structure becomes larger.When simulating the conditions of rock foundation soil,its natural vibration frequency is basically the same as m=30000(k N/m4).There is a difference in the natural frequency of the model using the pier-bottom fixed model and the pile-soil effect model.2.Using the response spectrum method,it can be seen that under the E1 seismic force,in the displacement of the main section of the main beam,the displacement and internal force along the bridge direction and transverse direction increase with the height of the pier,and the vertical displacement and internal force There is little relationship between pier height changes.The pier section has the same changing properties as the main beamsection.3.In the time history analysis method,it can be seen that under the action of E2 seismic force,the seismic responses of the soil mass to the main section cross-section of the structure are larger than those of the bridge,and the effect on the cross-bridge direction is as the soil mass ratio increases.Big and large.The seismic response of the structure is different from the model considering the pile-soil effect when the model is directly fixed.4.The use of lead-rubber bearings for seismic isolation of bridges can significantly reduce the seismic response of the bridge structure and provide a good isolation effect.