In view of the increasing urban traffic pressure in recent years, more and more urban elevated bridges can no longer meet the traffic needs, and the renewal and transformation of bridges is imperative. However, the renewal and transformation of bridges carried out under closed traffic will have a great impact on existing traffic. Starting from the aspects of improving, restoring and extending urban elevated functions, the project has carried out in-depth, systematic and comprehensive innovative research on urban elevated bridge renewal and reconstruction construction technology, and achieved the following results: 1. For the first time, research on the construction technology for improving urban elevated functions under uninterrupted traffic was systematically carried out. Aiming at the problems of insufficient functions of the two major types of existing elevated bridges, excessive node traffic flow and insufficient elevated clearance, bridge ramps were carried out. Research on construction technology for adding and overall jacking of bridges. Innovatively use post-demolition anti-collision wall bridge technology, large-span and large-section steel box girder segment cantilever assembly technology and prefabricated bridge technology to add existing bridge ramps; and carry out the overall jacking technology of multi-span simply supported beam bridges. Systematic research has solved many problems such as high steel support height, long linkage distance and high precision of synchronous control systems during the jacking process. A series of key construction technologies for uninterrupted traffic have been formed. 2. We have developed key technologies for the restoration and construction of urban elevated functions under uninterrupted traffic conditions. In view of the increase in the service life of bridges and the harm of overloaded vehicles, the cumulative damage to the existing bridge structure is increasing, and it is gradually unable to meet the needs of transportation. Construction will seriously affect traffic. Research on the replacement technology of the superstructure of existing urban elevated bridges has been carried out, effectively solving the traffic guarantee problem during the replacement of existing bridges with slab beams. Key technologies for the restoration and construction of urban elevated functions under uninterrupted traffic have been formed. 3. Research and development key technologies for the extension construction of urban elevated bridges under uninterrupted traffic conditions. Aiming at the problem that the existing urban elevated bridges extend to the periphery of the city, which seriously affects the traffic flow of existing intersecting roads, two major types of new bridge structures have been carried out, steel box beams and The research on the construction technology of cast-in-place beams has formed the key technologies for the push-up construction of steel box girders and the rotation method of cast-in-place box girders, which has effectively solved the traffic impact during the outer extension construction of urban elevated bridges, and achieved good results. The research results of this project have resulted in 3 authorized invention patents, 6 utility model patents, 3 published papers, 2 city-level construction methods, and 1 Shanghai City Engineering Construction Specification is editor-in-chief. The search results of the Shanghai Science and Technology Inquiry and Consulting Center of China Academy of Sciences and expert acceptance opinions believe that the research results of this project have generally reached the international advanced level. Through the combination of industry, academia and research, the project systematically studied key technologies for urban elevated renewal and reconstruction under uninterrupted traffic conditions, solved a series of construction problems in urban elevated renewal and reconstruction, significantly reduced the impact on road traffic, and promoted urban viaduct The further development of renewal and reconstruction technology has greatly promoted, and has cultivated a number of professional technical research and development and engineering project management teams. The research results have been applied in a number of key projects such as the addition of Humin Ramp, the repair of Wusong Bridge, the raising of the beam body of the Hangzhou-Shenyang Line, and the track bridge of Shanghai Line 11 across the S2 Expressway. Good social and economic benefits have been achieved. During the period, a total of 26 million yuan was generated.