Study On Technology Improvement Of Hyperbolic Arch Bridge In Detection, Evaluation And Reinforcement

Because of the long-year’s building, outdated maintenance and serious damage of the hyperbolic arch bridge, it is a very important and meaningful thing to test and reinforce it. However, currently existing hyperbolic arch bridge test content and method are not perfect. Moreover, it is necessary to optimize its technical condition evaluation. Study on reinforcement technology of hyperbolic arch bridge which the positive and negative bending moment too large of arch foot and the vault is flawed. This article studies on detection,evaluation and reinforcement technique of hyperbolic arch bridge with the way of theoretical research, finite element calculation combining test. It mainly includes the following several aspects:(1) Put forward improvement test ways in view of arch axis detection, concrete strength detection and so on, which provides basis for hyperbolic arch bridge test work.(2) The arch axis deformation is not classified The arch axis deformation is divided into "M"shape and uniform deformation. Use a software-MIDAS-CIVIL,building different span different rise-span ratio of plane truss bridge model and take vault deformation values as target parameters to analyze internal force deflection changes under different deviation value. In accordance with the principle that the change rate of internal force is the same, dividing vault deviation value into different interval and take the intervals as the boundaries of arch axis deformation rating scale, which perfect the evaluation criteria of hyperbolic arch bridge arch axis deformation.(3) The arch foot defined standards are not clear in hyperbolic arch bridge technique condition evaluation criterion. The article use a software-MIDAS-CIVIL, building different span different rise-span ratio of plane truss bridge model to analyze arch ring control section internal force, the change of the stress and bearing capacity under different displacement of arch feet. Taking the requirements of bearing capacity as the standard, concluding the arch foot displacement limit value with finite trial and grid curve method. Results show that the displacement of the arch foot, before has not yet reached the limit parameters approximate linearly with the increase of displacement of arch foot. So the displacement of the arch foot limit can be divided into three intervals as arch foot rating scale line that has yet to reach the limit of displacement, which perfect the hyperbolic arch bridge arch foot displacement evaluation criteria.(4) As for a problem that because of the too large bending moment value of vault, appearing damage of hyperbolic arch bridge, put forward a new method of externally prestressed reinforcement hyperbolic arch bridge and design two different forms of reinforcement. According to the principle that external prestressing, producing negative bending moment in the vaults "offset" positive bending moment vault in dead load, give amount of reinforcement and prestressed anchorage position calculation formula under different forms of steel bar arrangement. Use the finite element software to establish different span and rise-span ratio of plane truss model, analyzing the change of stress, deflection and bearing capacity of each section arch ring under different pretension value in two kinds of steel bar arrangement. Results show that use the way of the external prestressed strengthening vault is a good way to offset positive bending moment, lower arch deflection, improve arch section carrying capacity.(5) As Meng Yan bridge in GuiZhou province for an example, detecting and evaluating this bridge on the basis of exist hyperbolic arch bridge detection and evaluation combined with improvement of detection and evaluation. Using straight-line externally prestressed reinforcement this bridge on the basis of study on the prestressed reinforcement. Finite results show that reinforcement reduce the tensile stress in the down edge of vault and improve the bearing capacity of vault.