The Discussion On Design Of The Long Span Prestressed Concrete Continuous Rigid-Frame Bridges

Along with the development of transportation enterprise by the impetus of the international economy, the traffic volume is increasesing day by day, and the bridge enterprise is facing the stern test. In recent years, there are many long span prestressed concrete continuous rigid-frame bridges constructed in our country, at the same time, some problems have been exposed which are quite markable, especially the crack, the deflection and so on. It has aroused universal interests in the engineering field.In this thesis, the author carries out the structure analysis to the prestressed concrete continuous rigid-frame bridge at first, including the box girder and the substructure.Next, the problems, such as the crack, the deflection and the insufficiency of ultimate bearing capacity in the practical use, were analyzed. In addition, the author also discussed the disposition of pre-stressed steel, the size of the box section, the check in construction and the maintenance in the control and operation process and so on. It is also pointed out that, to solve this kind of problems, the most effective method is the appropriate arrangement of the nonprestressed reinforcement. The designer and the constructor should achieve the mutual recognition. Simultaneously, several proposals are put forward about how to enhance the security and the durability of the prestressed concrete continuous rigid-frame bridge.Finally, the author focuses on the prestressed concrete continuous rigid-frame bridges with the diseases above which could not be used as the normal. By collecting and analyzing multitudinous existing data, the model examples which have been strengthened and the newest research results, the author carried on the summary and the discussion of strengthening technology frome both the domestic and the other countries. It is the most effective and also the most applicable method to improve the stress of the diseased bridges by useing the externally prestressing technology.