Design Key Parameters for Simply-Supported Beam of High-Speed Railway in China

In order to guarantee the running safety and riding comfort of passenger train, the key parameters for bridge design of high-speed railway have changed to stiffness and deformation instead of strength. According to Code for Design of High Speed Railway, the common span bridges applicable to 350 km/h should meet six limiting values, including vertical deflection under the design live-load, vertical angle of the beam end, horizontal deflection, vertical relative deformation of the two rails in one-line, the arch value on the residual creep and vertical self- vibration frequency. In addition, if there need to train-bridge coupling vibration analysis, the acceleration at bridge deck should not exceed 5.0 m/s2 and the dynamic performance of train should meet the running safety and riding comfort requirements. The formulation background of above-mentioned indexes are introduced in this article. Then, taking 32 m double-line simple supported box girder as an example, the differences between actual design parameters and limits of design code are analyzed, And combined with field tests, the conclusion is made that the actual design parameters are beam end folding angle and the arch on the residual creep. These two indexes are formulated to ensure the high smoothness of track structure. On the basis of above research, proposals for bridge design of higher speed railway are put forward.