Static Analysis To Small Box Girder Bridge Which Supported First Simply Then Continuously Under Service Loading

Recently, the highway had unprecedented developed with the enhancement of comprehensive national power in our country. The features of highway are fastlysecurity and comfortable. In order to provide fastly reposeful and comfortable driving condition, high qualities of the bridges were required in the highway.The high qualities were better continuous performance and less expansion joints etc.Medium-small span bridges occupy very highly ratio in the highway. Because of the firstly simply supported then continuously supported small span box girder combines the advantages of the continuous beam bridges and the precast beams' batch production, it had been widely applied and developed.Firstly, this thesis summarizes development situation, present research status, analysis theory and method of the simply-supported-to-continuous structure systerm.Secondly, using the finite element software Midas Civil to analyze the construction procedure of the simply-supported-to-continuous structure systerm detailedly.Then find out the change law of the main girder's internal forces, deflections and stresses. Especially, the redistribution law of the internal forces and stresses which induced by prestressing tendon and shrinkage and creep of concrete pre-and post the system transformation.Thirdly, amply study on pouring order of concrete in the post-continuous end region, tension order of the post-continuous prestressed renforcement and removal procedure of the temporary bearings. Then finding out their reasonable procedure to guide the construction.Finally, analyze the finished stage of five spans firstly simply supported then continuously supported small span box girder. Search for the effects of temperature gradient to this structure systerm.