Research On Key Technologies Of Construction Monitoring Of Long-span Rail-cum-road Steel Truss Cable-stayed Bridge

With the continuous improvement of relevant structural theory and the continuous development of construction level,steel truss cable-stayed bridge has very significant advantages in the structural selection of long-span bridges,and has gradually become the preferred bridge type for long-span rail-cum-road bridge.The long-span steel truss cable-stayed bridge is a complex high-order statically indeterminate structure,which has high requirements for the linearity and internal force of the structure during construction.During the construction process,the structure and internal force of the structure must be effectively monitored and controlled to ensure the normal construction process.Therefore,it is of great significance to improve the construction technology of bridges to study the construction monitoring technology of long-span rail-cum-road steel-truss cable-stayed bridges.In this paper,the key technology of construction monitoring of long-span rail-cum-road steel truss cable-stayed bridge is systematically studied based on the project of Dalian Islet-Xiaolian Islet Waterway Bridge of Pingtan Strait Rail-cum-Road Bridge.This paper summarizes the development status of construction monitoring of long-span steel truss cable-stayed bridges.The system explained and studied the bridge construction monitoring control method and the typical structure calculation method.Using the research method of structural simulation,the finite element model of the Dalian Islet-Xiaolian Islet Waterway Bridge was established.The combination of the minimum bending energy and the influence matrix method was used to determine the ideal bridge formation state,and the whole process simulation of the construction phase was established based on the target state model.The sensitivity analysis of the key structural parameters of the bridge was carried out,and the sensitivity of each parameter to the structural behavior was obtained,and the sensitive parameters were determined.Based on the results,the least square method was used to identify the sensitive parameters.Calculated and analyzed the structural behavior of the closure in the key working conditions,including the different effects of the closure adjustment measures on the structure,and gave reasonable suggestions for the closure process through calculation and analysis;analyze the structural behavior and simulation calculation results after the final cable adjustment to verify the effectiveness of construction monitoring and provide reference for other similar bridges.