Research On The Incremental Launching Technology Without Temporary Piers Used In Long-Span Prestressed Concrete Continuous Girder Bridge

The incremental launching technology has been a main construction method in short and medium-span bridge construction because of the prominent advantages such as less occupied space under the bridge, higher mechanization, lower input cost, better stability, safety and reliability. This paper is to expand the use area of this mature technology from short and medium-span bridge to long-span bridges, and without temporary piers in min span in order to ensure the navigation.First of all, in this paper, the problems existed in the construction technology of the continuous girder bridge and the difficulty of using the incremental launching technology in navigation span are analyzed, and the method of setting steel brace on the piers instead of the temporary piers in the navigation channel is presented. Secondly, based on the prestressed concrete continuous beam bridge with constant section (5 X 64 meters span) in the north auxiliary navigation channel of the Hongdu Bridge in Nanchang in Jiangxi Province, a method of setting steel brace in the process of incremental launching has been put forward, structural design and calculation of the bridge at the stages of construction and completion have been conducted, the feasibility of the proposed method is verified, and the research on construction techniques have been also performed. Finally, the analysis and comparison in construction and cost between the incremental launching method and cantilever casting method are carried out.The results indicate that the incremental launching technology without temporary piers is feasible to be used in long-span prestressed concrete continuous girder bridge, and it has better performance in construction quality, safety. schedule and cost control etc as compared with the traditional cantilever casting method. Therefore, the incremental launching technology can be widely applied in the construction of long-span PC continuous beam bridge with constant section.