Analysis Of Prestressed Concrete Continuous Girder Bridge Diseases And Externally Prestressed Reinforcement Technology Research

In recent years, Prestressed concrete continuous girder bridge has gotten rapid development with advantages of strong spanning ability, good mechanical performance and beautiful appearance in our country. But excessive cracking and deflection also exist generally. Cause of these problems is analyzed in this article in the view of design, particularly in creep effect of concrete and shear lag effect of box girder, which will provide reference for the design.The deep discussion on the reasons for stress characteristics of box girder and deflection of PC girder bridge shows that inaccurate calculation of creep effects mainly causes the excessive deflection of long-span PC girder bridge. Deeply study the current commonly used methods of bridge design software and their defects of calculating creep effect, put forward and realize the calculation method of creep effects with three-dimensional entity unit, which is based on ANSYS and joined relaxation process affect of prestressed girder, and analysis the creep effect of three line viaduct, conclusions which have certain reference value to the design are gotten in the end.Analyze common cracks and causes estressed girder bridge, and analyze the effects of Shear lag effect on box girder bridge with the viewpoint that Shear lag effect has great influence on cracks of box girder brige. Particularly analyze the shear lag effect of three line viaduct, and study the wide span ratio, thickness of top plate, length of wing cantilever, effect of web leaning on the shear lag effect, the results show that the impact of wide span ratio and length of wing plate cantilever is significant. From the viewpoint of reducing the shear lag effect, Suggestions of certain value of are raised.Common methods for the bridge reinforcement are studied and discussed, and analyze some key technical problems of external prestressed strengthening method. Externally prestressed reinforcement is carried out on three line viaduct, and the results show that the method can effectively correct the deflection with obvious reinforcement effect.