Research On Mechanic Behavior And Reinforcement Technique Of Assembly Hollow Slab Bridge

Assembly hollow slab bridge is a structure type which is widely used in medium and small bridges. Assembly hollow slab bridge carries the advantages of simple structure, clear force, small building height, beautiful appearance, convenient construction, mature technique and good adaptability. The past design theory for assembly hollow slab bridge has its limitation, and with acceleration of the pace of China's economic construction and the modern traffic, hinge joints in assembly hollow slab bridges have been damaged in different degrees due to its large transverse force.The destruction of hinge joints represents the damage of transverse connection. It causes some other diseases in upper structure of assembly hollow slab bridges directly, and even single slab bearing phenomenon. Therefore, study on reinforcement technique of hollow slab bridge aimed at its diseases has important theory significance and economic value. The main research contents and conclusions of this paper are as follows:(1) Summarize the typical diseases of assembly hollow slab bridges through joints, pavements and beams. Analyze the causes of all kinds of diseases, and put forward two reinforcement methods for hollow slab bridges:bridge deck strengthening method and lateral external prestressing reinforcement method.(2) This paper studies from the design theory --- hinged plate method to study the transverse connection form of assembly hollow slab bridges. The lateral load distribution coefficients of a 10-meter span simply supported hollow slab bridge under vehicle load were calculated respectively by both hinged plate method and rigid plate method. The calculation concluded that the transverse distribution coefficients show little difference when the transverse connection of hollow slab bridge turns from joint to rigid connection.(3) Establish three kinds of models of assembly hollow slab bridge according to three different methods by using ABAQUS finite element analysis software. The results of different models were compared to seek the most reasonable numerical simulation method. The analysis established the foundation for the research of strengthening technology below.(4) Put forward to use the high-strength and light-weight concrete in bridge deck strengthening method. Analyze the influence of strengthening layer's thickness to structure's internal force. Compare the strengthening effort of bridge deck strengthening between using common concrete and high-strength light-weight concrete.The contribution of reinforcing steel bar to the whole structure is also studied. The results show that bridge deck strengthening method can effectively improve the stress status of hollow slab bridge.(5) Analyze the strengthening effort of lateral transverse prestressed reinforcement applied to old bridges and new bridges. Study the influence of the external prestressing tendons' vertical position to the reinforcement effort. Use both bridge deck strengthening method and lateral transverse prestressed method to reinforce hollow slab bridge and analysis its effort. It concluded that transverse prestress can effectively improve the stress status of hinge joints and increase the lateral stiffness.