The Research On Deflection Of Long Span PC Continuous Rigid Frame Bridges

With the development of the national infrastructure construction, the continuous rigid frame bridge with its structure characteristics, has become one of the main type of bridges in the highway construction. But along with the more and more long-span continues rigid frame bridge constructed, deflection of the concrete has been become a serious problem, influenced the popularization of this type of bridge in the highway engineering in the further.In prestressed concrete structures, they are important to know how much the prestress losses is and estimate the creep exactly for the deflection of the structures. Therefore, the prestress losses and the creep are the main reasons why the deflection of the girder is larger than that of code.This dissertation takes the example of Huangshi Bridge,a 245m long prestressed concrete box-girder continuous rigid frame bridge,adopt the method of Finite Element Analysis (FEA) method to analyse the stress features of this bridge.Mian research works of this dissertation are included below:(1) Make a review of development and researches about long span prestressed concrete continuous rigid frame bridges in China and abroad, disease status and calculation means of deflection.(2) This thesis introduces mechianics and cause of deflection. We introduce the impact of prestressing tendon losses and shrinkage and creep to total structure, and the impact of long-term analysis of deflection.(3) By the method of FEA, a structural analysis is made about huangshi Bridge, a 245m long prestressed concrete box-girder continuous rigid frame bridge. In the process of post-operation, this bridge appears a large deflection in cross-bridges. Through the FEA, based on the diseases of deflection, we analysis the impact of deflection due to prestressing tendon losses and the concrete shrinkage and creep on the bridge . On the basis of theoretical result, we make recommendations of preventing deflection.(4) Provide the treating ways to reduce deflection of long span prestressed concrete continuous rigid frame bridges,from the factors of design,constructing,etc.