Study On Anchor Spray Cement Concrete In Reinforcing Double Curved Arch Bridge

Because of the merits in the structure, such as novelty, light, saving material, convenient for construction, the double curved arch bridge spread all over the country and made a great contribute for the development of our country's highway and bridge causes. However, the double curved arch bridges had inbonr demerits for the design lever and the load criterions on the low side, and the steel was scarce in the structure. When the bridges were loaded heavily and in heavy traffic for a long time, all of them had some damages after some periods of usage. This dissertation summarizes and analyses the damage types and reasons of the double curved arch bridge, studies the reinforcing method of shot concrete, which is suit for the double curved arch bridge.The double curved arch bridge is a space structure. In order to ascertain the bearing capacity of the double curved arch bridge after being reinforced, the damages of the original bridge should be considered synthetically. This dissertation introduces relative equations of nonlinear finite element design theory about using shot concrete reinforce the double curved bridge, and considers that the junction plane of the new and the original concretes is weak, for there are a lot of crack in the concrete surface before reinforced, which also distribute broadly. Suppose the crack firstly appear in the junction plane of the new and original concretes, and further expand along the original crack trace, on basis of which the rigidity of cracking elements are revised. After considering each kind of nonlinear factors, every element stiffness matrix is synthesized a synthetical stiffness matrix, and then the computation is carried on.Through the project example, this dissertation establishes the finite element mode of the main span of the bridge, contrasts and analysis the deflection and the stress value of the original and the reinforced bridge in different load conditions, as well as the actual value from the load experiment, to check the reinforcement result and model; and then do a preliminary study on optimization design of the reinforcement thickness of the main arch ring.Finally this dissertation obtains the appropriate anchor depth, and suggests taking the round steel as the anchor bolt; detects the cohesional strength of the new and the original concrete considering the effect of the anchor bolt, which is much bigger than the tensile strength of the concrete, through the anchor bolt pulling capacity experiment and the cohesional strength of the new and the original concretes experiment. So the reinforcement method is proved to be reliable.