The Research About Closure Of Prestressed Concrete Continuous Rigid Frame Bridge

The techniques of designing and constructing continuous rigid frame bridge developed rapidly. As many large span rigid frame bridge emerge, all these facts show that our status of bridge construction in China. Recent years, many investigations about cracking down deflection of continuous rigid frame bridge have been done by scholars who also made lots of practical improvement. Bad stress state after the bridge is completed and Serious Eccentric in Main Pier can be caused by Shrinkage and creep as a problem of continuous rigid frame bridge. In this article mainly analysis about the above problems has been done by the author.Due to the shrinkage of concrete creep effect, deflection in the mid-span and eccentric in the pier will seriously appear after the bridge construction; serious eccentric in the pier will lead local tensile stress, and the tensile stress could lead to the safety problem during the operation. In order to improve the eccentric after the construction, pushing construction should be used. The calculation method of main pier anti-push rigidity of continuous rigid frame bridge and deduced the analytical formula of jacking force are in detail analyzed by the author in this paper. The analytical formula of jacking force is close to the result that is analyzed by finite element method, we can use this method after the result multiplied by the coefficient1.2. At the same time, through the analysis other conclusion can be found that the value of the jacking force should not be too large, and its value to improve70%of the value of the post-shrinkage and creep effects can be.Close concrete quality of continuous rigid frame bridge play a critical role of full-bridge, according to many bridges that have been built, crack usually appears in the bottom slab of closure segment, sometimes concrete crack also can appear in the bottom slab. It related to not only design but also construction technology in the construction process. According to the analysis, environmental temperature has a great affect in the close concrete during the closure segment construction, and the usage of rigid support and temporary prestressed reinforced could improve the affect effectively. The shortest temporary prestressed reinforced in the bottom slab can be only tensioned, and its tension tonnage values can be considered for the design of tension value of35%.In this paper, the bridge linear effect of the program on the bridge is greater than the impact of structural forces and symmetric closed is more favorable than asymmetric close to the bridge, which can be found in the different program of close analysis.