.200 Km Of Speed Railway Prestressed Concrete 32mt Beam Torsion Problem Under Study

In the engineering project of railway-speeding transition by electrification on XX Speeding Line, deflection occurred in part of 9753-I type 32m prestressed simple supported T beams of A and B two large bridges. According to that phenomenon, work of investigation, test and theoretical analysis are developed in this paper, so that the functional performance and operation reliability of these beams are synthetically evaluated. The main work is as followers:1 Appearance detection, dynamic load test, static load tests and strength test are organized in the field. The deflection phenomenon is commonly existed in the two bridges, which are confirmed in appearance detection. The results of dynamic and static load test shows that, the functional performance of these beams are normal and meet the requirements of design and codes.2 Static and dynamic analysis by finite element method for normal beams and the beams with deflection are proceeded, so that the rationality of design are confirmed and test results are verified which fit close with the theoretical analysis results.3 The record data of beam-fabricating provided by the fabrication yard are investigated and analyzed, which showed that the key cause for the deflection is the configuration control during the fabrication, not the other mechanic defects.4 The control technology such as stretching of prestressed reinforcement and mechanic parameter are analyzed , then the limit deflection value of the beams are deduced ,and safety performance of the structure are judged which met the requirement of safety operation.5 Based on the conclusion of this paper, great work of beams-exchanging for the bridges is avoided, so that large amount of funds are saved. And summarize of design and construction in this paper can be the reference for engineering projects of the same kind.