Bridge Diseases And Repair Methods Research In Xinjiang Region

Because of the special climate characteristics in Xinjiang region such as dry climate, cold and long winters, high summer temperatures and large day-night temperature difference, frequent sandstorms in spring and autumn weather, etc. the bridge structure there was caused unique features of diseases. Under the action of large temperature difference, repeated freezing and thawing, rain and snow, permafrost, the concrete bridge structures prone to large cracks, these cracks continue to expand, which will accelerate the internal structure of concrete carbonization and corrosion of steel. Repeated freezing, winter snow and ice melting and thawing permafrost will bring about piers tilt, cracking and corrosion of reinforcement and so on. Sandstorm causes blocking of bridge opening and outlet pipe, which will affect the function of drainage and flood discharge of the bridge. With the climate warming in Xinjiang, seasonally frozen soil time gradually shortened, depth of permafrost decreases, bridge foundation construction will cause disturbance to the permafrost, these factors will lead to melting and sinking of permafrost foundation, tilting of subsidence base, eventually leading to the load carrying ability of the bridges.Before reform and opening up, the economic foundation of Xinjiang region was weak, transportation business was underdevelopment, and bridge load rating was in low grade as well as deficiencies in design and construction. With the economy develops there, the bridges built in early stage can't meet the needs of the local transport industry any longer, overload is becoming more and more common. Under the influence of all sorts of natural environment and vehicle load, these early built bridges are in serious conditions, and some even become unsafe ones. This is detrimental to local economic development, and even endangers people's lives and property security. Therefore, maintenance and reinforcement to these bridges has become an urgent affair, but there isn't a corresponding maintenance and reinforcement method to the special disease characteristics of Xinjiang bridges yet.Based on the quality inspection to Yili Bridge, Tarim River Bridge and Provincial Highway 303 medium-sized Bridge in Xinjiang, this thesis analyzes and summarizes a number of diseases of the bridges, mainly on the following aspects:1. A more comprehensive induction and analysis to the bridge diseases mechanism of Xinjiang region is conducted for the first time.2. By comparison and analysis of quality inspection, static load test and dynamic load test of Yili Bridge and Tarim River Bridge in Xinjiang, the deformation and displacement law of bridges in real load effect and design load function is derived.3. After comparative analysis the results of static load test and dynamic load test with the calculation results of MIDAS finite element software, comprehensive assessment of bridges'carrying capacity and working conditions is worked out, and then corresponding maintenance and reinforcing scheme is given.4. The corresponding prevention, maintenance and reinforcement measures to the bridge diseases in Xinjiang region were given according to its special disease characteristics.