Research on Dynamic Behaviors of 32m Prestressed Concrete Simply Supported Box Beam in High-speed Railway

摘要

32m simply supported box beam is a standard beam which has been widely used In Chi -nese high-speed railway. So,it is r necessary to do an indepth analysis of the dynamic behaviors pa -rameters(include the natural frequency of beam , dynamic r deflection, lateral amplitude, vertical amplitude and vertical acceleration) of 32m girder. In this paper, the theoretical r analysis model of 32m simply supported box beam were built and the dynamic response ,the potential resonance frequency , the r resonance speed and super -harmonic resonance speed of it subjected to the CRH multiple unit were researched in detail. The r comparisons between the calculated results and measured results were made. The research results show that, (1)The dynamic r behaviors of girder is good. The lateral and vertical rigidity of girder are much more than the limits specified by relevant r code and design file. (2)The resonance of 32m girder would not occur at current operating speed. The peaking effects of the r vertical dynamical response at mid -span of 32m girder would appear when the speed of CRH mul -tiple unit is close to the r super -harmonic resonance speed , however, the measured value of the vertical dynamic response were still small because of r the low incentive energy of CRH multiple unit with low mass and short marshalling. (3)Under the present designed lateral and r vertical rigidity of girders ,the tested dynamic response of different 32m simply supported box beams arranged with r continuous equal span are similar. The periodicity irregularity effects of it did not appear.