English：

This paper studies the key construction technology of urban inner ring viaduct expresswaynetwork project, mainly introduces the overall lifting of the old bridge, the laying of polyester alloyformwork, the pouring of the central isolation pier, the installation of the expansion device, the installationof the seismic isolation bearing, and the application of the prestressed intelligent tensioning system.Engineering practice shows that the use of the overall lifting technology of the old bridge can adjust theposition and height of the old bridge without removing the old bridge,which not only saves the project cost,but also reduces the impact on the surrounding environment. The laying of polyester alloy formworkprovides a more efficient and durable formwork solution for bridge construction,which improves theconstruction efficiency and the overall quality of the bridge. The automatic formwork trolley is used in thepouring of the central isolation pier,which realizes the automation and precision of the concrete pouring,and ensures the appearance quality and dimensional accuracy of the isolation pier. The installation of noise-reducing expansion device can effectively reduce the noise generated by bridge expansion and improve thequality of living environment of surrounding residents. The friction pendulum seismic isolation bearingenhances the seismic capacity of the bridge and ensures the safety of the bridge structure. Through theprestressed intelligent tensioning system, the prestressed tensioning process is accurately controlled, andthe bearing capacity and durability of the bridge are improved. Based on BIM technology to check thethree-dimensional sight distance, the bridge sight distance can be simulated and analyzed beforeconstruction, and potential problems can be found and solved in advance to ensure driving safety.