Mechanical Performance Analysis Of Precast Segment Small Radius Rigid Frame Ramp Bridge In Urban

Since the 1980s,due to the acceleration of China's economic development,there has been a trend that the population of villages and towns gather in the city,which leads to the dense population in the city and brings great pressure on the urban traffic,more and more urban interchange system construction and put into use.Ramp bridge,as the key engineering control node connecting the upper and lower roads of urban interchange system,plays a self-evident role.However,because of its small radius,narrow deck width and complex stress,how to accurately calculate its internal force and deformation has become a key problem.Therefore,it is necessary to study the structural calculation of ramp bridge.In this paper,a segment prefabricated rigid frame ramp bridge in the rapid engineering of the Fourth Ring Road and Dahe road in Zhengzhou city is taken as an example,and the micro length element is used to simulate the glue at the joint.The finite element model of the whole bridge is established to calculate the stress,internal force and deformation of the real bridge in the main construction stage.For segmental precast assembled beam bridge,the tension of temporary prestress is directly related to the quality of assembly,so it is very important to adopt the correct method to apply temporary prestress.Under the condition of meeting the construction requirements,the temporary tension of the bridge is calculated,and a set of tension scheme of temporary prestress is established.Secondly,on the premise of not changing the pier height and span,this paper studies and analyzes the influence of the change of curvature radius of rigid frame ramp bridge on the internal force and displacement under the action of dead load,as well as the influence of the action position of vehicle load on the internal force.According to the prestress effect of rigid frame ramp bridge with different curvature radius,this paper analyzes the relevant laws of static characteristics of rigid frame ramp bridge.Finally,in order to study the dynamic characteristics of the small radius rigid frame ramp bridge,this paper uses the response spectrum analysis method to analyze the internal force of the structure under different directions of seismic wave excitation,and summarizes and analyzes the dynamic correlation laws of the rigid frame ramp bridge.In view of the above analysis,the stress law of small radius rigid frame ramp bridge is summarized,which provides feasible suggestions for the design and construction of similar structures in the future.