Application And Research Of The Bonded Prestressed Reinforcement Systems On Prestressed Concrete Box Girder Bridge

With the rapid economical development of our country, traffic volume and load are growing, requiring higher standards for bridges. However, relevant statistics show that a lot of substandard bridges are still running and rebuild these bridges is apparently impossible. Therefore appropriate strengthening measures are required to ensure roads passable.Prestressed concrete continuous girder bridge, a very common type of bridge, is suffering more and more serious bridge disease, so study on appropriate reinforcement and maintenance on this type of bridge is crucial. Starting with the common damages of prestressed concrete continuous girder bridges, this dissertation conclude the main forms of bridge diseases and some popular reinforcement methods. Moreover pros and cons of every method are listed.The bonded prestressed reinforcement system is a whole new structural design, which applies new materials including mild galvanized steel wire, HTCM high-performance tensile composite mortar and AP multifunctional composite resin mortar. Because of its combination of strengths such as its simple anchoring, convenient stretch-draw,excellent durability and remarkable reinforcing effect, this system has been valued at home and abroad. To research the application of this reinforcement technology on prestressed concrete continuous girder bridges, the main text of this dissertation is carried out by the following aspects.(1) The basic theories of bonded prestressed reinforcement system are introduced including usage, materials and strengthening principles, which are elaborated with calculations on capacity of normal and sloping section in flexural member.(2) Combined with the survey report of Baizhang bridge, this dissertation models this bridge example by applying FEM software MIDAS civil. Besides capacity assessment of the bridge present is carried out, which shows that the shear capacity of oblique section is deficient and the principal tensile stress of web in the mid span section which about from piers a quarter of the length of span is greater than the requirement of the specification. Therefore it is necessary to reinforce its sloping section.(3) After the selection of a variety of reinforcement scheme, bonded prestressed reinforcement system is finally chosen to reinforce the sloping section, and MIDAScivil is applied again to simulate the reinforcement. The comparison between the analysis results before and after reinforcing tells that the reinforcement improves the shear capacity of oblique section significantly and the principal tensile stress of web meets its objectives mostly. It just shows the reinforcement achieve the goal. In addition,the factors that may effect the strengthening are discussed, such as different kinds of high-performance tensile composite mortar and the size of the web, etc.Wish the above application research of the bonded prestressed reinforcement system on prestressed concrete continuous girder bridge providing some reference for the reinforcement of this bridge type by using the system.