Application Of Bridge Rectification Technique

The thesis makes a study on deviation of the medium-span bridges and small-span bridges which is widespread but easy to be ignored by people. First, it classifies longitudinal and transversal move of bridges caused by various internal and external factors. Then damage causes are checked and analyzed by the numerical method on the basis of above work. Besides, the simulated analysis is used in the process of bridge deviation and construction of rectifying deviation based on the related projects. Finally, the reasonable scheme for construction and monitoring bridge deviation is proposed, and the reasonableness of the scheme is verified by bridge-deviation construction on the spot. Through above systematic research, conclusions can be drawn as follows:(1) There are mainly internal and external factors to cause the bridge deviation. The internal factors contain bridge surface curvature, the layout of supports, concrete shrinkage and creep, etc. The external factors include temperature affection, vehicle load, expansion joints jammed, differential settlement of supports, etc.(2) The temperature affection is the main factor to cause the bridge deviation, which is especially obvious to the curved bridges. Besides, the impact of the live load should not be neglected. Without considering the impact of accidental events(such as earthquake, car and boat clash), deviation amount caused by the impact of temperature is frequent larger than the total amount of the all factors.(3) Curvature is also a vital factor to bridge deviation.To longitudinal displacement, the smaller the radius of curvature, the smaller the displacement; to transversal displacement, the smaller the radius of curvature, the larger the displacement.(4) The boundary conditions of beams’ rising and lowering temperature are different because of the jammed expansion joint that limits the extension of beams but has nothing to do with shortening of beams, which will lead to the creep of beams under the impact of temperature as well as the large increasing of deviation amount. The problem stated above is especially obvious to curved bridges.(5) Layout of supports greatly impacts the beams’ deviation. The thesis analyzes two groups and four typical layout of supports. According to the analysis, the best effect to prevent beams’ deviation is that fixation should be given to the middle parts of the curved bridges while the layout of longitudinal move and lateral restraint should be given to other kinds of bridges.(6) The force in the process of jack-up for bridges with beams is complex. So it’s better to monitor the stress on the section during the jack-up in the construction. Moreover, the adjacent pivot points should be jack up to some degree in order to reduce the stress peak on the section of the jack-up.(7) There are too many bridge spans in the curved bridges which also can influence the change of deviation amount and especially impacts the longitudinal displacement.