Structural Reinforcement Of Reinforced Concrete Box Arch Performance Model Test And Design Methods

There are many kinds of the strengthening methods of reinforced concrete box arch. The more commonly used methods currently are the technique of anchor spraying, Fiber-reinforced plates, the technique of using reinforced concrete yoke to strengthen bridge arch, the technique of using bonded steel angles, the technique of using Steel wire mesh with polymer mortar. The technique of using reinforced concrete yoke to strengthen bridge arch is widely used in the structure reinforcement due to the method's simpleness. But the deep research in the strengthening effect of the method and strengthening design is lacked. Based on an actual project, the paper does some necessary model test research on the strengthening method and performance about the strengthening design of reinforced concrete box arch (the technique of using reinforced concrete yoke to reinforce the main arch ring and using polymer mortar to deal with interface),and home discusses its strengthening design theory and methods .1 .Rechecking the calculation of the actual bearing capacity of the reinforced concrete arch bridge, and bringing forward the method of using yoke to strengthen reinforced concrete bridge arch. After strengthening, recheck the bearing capacity of the arch bridge again. The conclusion of the finite element analysis of the bridge after strengthening is the bridge bearing capacity is enough to the actual traffic load.2. Research on five reinforced model beams has shown: (1) The bearing capacity and rigidity of beam after reinforcement are all improved effectively. (2) The section strain of strengthening beam changed linearly in the whole process from the beginning of upload to the yield of ordinary steel bars, the reinforced design of the section could be designed on the method of《Design specification for reinforced concrete》(GB10050-2002) .(3) Ordinary steel reinforcement beams bending damage occurred. High-strength steel reinforcement beams interface bonding damage occurred. When the damage happened, high-strength steel was not on yield strength. (4)Reinforced structure make the strain of steel bars lags behind the strain of reinforcement about 500-800με.3. The design method of the reinforcement beam cross-section bearing capacity is discussed. The delayed response of reinforcement bars is input, the formula of calculating the bearing capacity of reinforced concrete beams is erected. The calculation results and experimental values explained: Considering strain delay or not has little effect on bearing capacity of the reinforcement beam, about 5% range. However, the balance limits depth of relatively compression zone of reinforcement beam cross-section value greater impact.4. Five shear reinforcement models test is carried on, and the design method of shear bearing capacity is discussed. (1) The strength of stirrups used in the reinforcement should not be too high, otherwise it can't be fully utilized. (2) Analysis of shear strength values compared with the experimental values shows that shear bearing capacity of the shear reinforcement beam according to the《Design specification for reinforced concrete》(GB10050-2002) calculated values is a bit high. Therefore, the formula of calculating the bearing capacity of reinforced concrete beams was amended in this paper. From the comparison with the test results we can conclude that the shear strength of reinforcing beam has a more appropriate security after amended.