Study On Detection And Assessment Of Existing Masonry Arch Bridges

Bridge plays a decisive role in the social traffic system, and about 70 percent are arch bridges among highway bridges in China. With the increase of service life and traffic volume, and overloading, more and more diseases occur in existing bridges to some extend. If not inspected and reinforced timely, it will affect the normal service ability and even cause traffic accidents. The urgent work faced is how to choose an appropriate way to inspect existing bridge and evaluate bearing capacity. In this thesis, inspection methods of masonry arch bridge are summarized, and some evaluation methods of bearing capacity are discussed, and the main works here is as fallows:On the basis of related literature, in this thesis the main inspection method for masonry arch bridge is summarized, and the difficulty is pointed out which the masonry arch bridge lies in inspection. What is focused on is the evaluation method of load-bearing capacity of masonry arch bridge. In theory, the live load effect on the arch is weakened as the action of filler dispersion and the role of anti-push arises because the side walls constraint the arch longitudinal deformation produced under live load. By numerical calculation, the changes is analysed in stress and deflection of the arch in considering and not considering the effect of filler and side wall, Further the influence degree is analysed of filler and side wall to the stress and deflection of the arch with the different ratios of rise to span. On the basis, reduction factor is given to take into account of live load effect of filler and side wall, and the calculation expression is proposed.According to the proposed reduction factor of live load effect, redress the calculation expression, which is used to evaluate the bridge bearing capacity, based on test results in "Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridge" (issued). On the other hand, taking into account the difference between the impact factor tested from load test and that calculated based on structure fundamental frequency, the live load impact factor is redressed in the calculation expression for evaluation of load-bearing capacity of masonry arch bridge. The method for strain test is discussed in masonry structure, and the inadequacy of test methods is pointed out nowadays. A test method is given by rigorous derivationTo verify the reliability of the formula, respectively evaluate the load-bearing capacity of Fushun HongQi stone arch bridge and Jiyu Weishui concrete masonry arch bridge in accordance with revised expressions, which will be more in-depth research on a certain reference.