The Study On Design Method Of Prestressed Tendon Layout Of Long-span PC Continuous Rigid Frame Bridge

Long-span prestressed concrete continuous rigid frame bridge have many advantages such as reasonable structure stress,large span capacity,ease of construction etc.But,many problems are exposed in the application of long-span prestressed concrete continuous rigid frame bridge.It becomes necessary to perform a further study on the design theory of long-span prestressed concrete continuous rigid frame bridge to solve these problems.Based on the rational completion status of long-span prestressed concrete continuous rigid frame bridge and starting from the basic concept of prestressed concrete structure design,This dissertation explores a new optimization design method of prestressed tendon layout for long-span prestressed concrete continuous rigid frame bridge.(1)Based on discussing the problem of the long-term deflection and crack of box girder and its research status on long-span prestressed concrete continuous rigid frame bridge,this dissertation generalizes and summarizes the optimized design of longitudinal prestressing tendons?transverse prestressing tendons and vertical prestressing tendons on the continuous rigid frame bridge and introduces some work about the rational completion status of beidges in the present.(2)Finite element analysis software of bridge design was used to contrast and analyze internal force,deflection and stress of three finished actual continuous rigid frame bridges,and the relationship among the bending moment of resistance of prestress,the bending moment produced by the dead load,deflection and stress was discussed,finding that the bending moment of resistance of prestress was greater than the bending moment produced by the dead load was the necessary to reduce the long-term larger deflection of continuous rigid frame.(3)In this dissertation,the prestressed tendon was taken as an adjust inhaul cable,and the internal force equilibrium and stress threshold were taken as constraint conditions of the design of prestressed tendon of large-span prestressed concrete continuous rigid frame bridge.The design of prestressed tendon of roof and floor was studied by using theoretical analysis and numerical calculation,and a new method of optimizing prestressing tendon design was put forward.(4)The method of optimizing prestressing tendon design proposed in this dissertation was used to optimize prestressing tendon of large-span prestressed concrete continuous rigid frame bridge,and made a contrastive analysis of it and the calculated results of the original design,to verify that this method significantly improved long-term large deflection of prestressed concrete continuous rigid frame bridge,make the finished state of this bridge tending to be more reasonable.In this dissertation,the research results can provide the bridge design with valuable reference.