The Finite Element Analysis Of Old Bridge Strengthened By High-tensile Bolt And Dimension Optimum Of Anchorage

The high-tensile bolt anchorage system through tensioning the longitudinal linear prestressing high-tensile bolts under the beam to realize the application of the exteral reinforcement prestressing, and which was anchored by the bearing anchorage in the anchor-side. And the anchorage was fixed on the bottom of girder by prestressing which provided by the vertical high-tensile bolts. The level prestressing was transferred to the beam rely on friction between the beam and transmisssion equipment. At last, the polymer mortar was sprayed on the bottom of the beam, the reinforcement has completed at this point. The methord is not only simple, but also can ensure the integrity of the structures. The old and new systems can work coordinately, and it has overcome the stress hysteresis of other methods. In addition, it can also reduce the structural deflection and crack width, improve the structural carrying capacity, the resistance of cracks significantly and the stress state of the structures effectively.In this paper, finite element analysis model was based on the destructive load test beam and simulated limited load. The stress of high-tensile bolt anchorage system and anchorage steel plate was analysised in the model. According to the calculation results of the finite element analysis model and destructive load test, comparative and judge the reinforcement method whether it is reasonable, and anchoring plate size whether can meet the design requirement. The high-strength bolts optimal design method was proposed. In this paper, the following works have been carried out:(1) Understand the bridge reinforcement method, as well as the research status of the bridge reinforcement method and anchoring device at home and abroad.(2) This paper introduces the high-tensile bolt anchorage system composition and the method of reinforcement construction technology of it, the system failure load test in bonded state are briefly introduced in this article. According to the basic theory of finite element method, mechanical constitutive relations of materials and stress characteristics of components, the high-strength bolt anchorage system and ultimate load were simulated in ANSYS software. (3) The failure characteristics of concrete, concrete cracks development and distribution and the stress distribution characteristics of anchoring plate were compared between the simulated results and the destructive load test data.(4) The load-deflection curves of reinforced beam, stress-strain and displacement distribution of anchoring steel plate were received. The results show that the finite element analysis results which has a a good precision are in good accord with the experimental results.(5) According to the results of finite element analysis, size optimization design of the anchoring plate has been done, and four types of anchoring steel plate were computed respectively to get the optimal size. The method provided some theoretical reference for high-strength bolts anchorage system design and is of certain guidance for bridges reinforcement field.