Vibration analysis of medium and small span bridges subjected to mixed marshalling freight trains

It has been reported several times that train derailment occurs when mixed marshalling freight trains traverse bridges at high speeds in China. This study aims to explain this phenomenon numerically based on the train-bridge coupling vibration theory and its associated computer program. The train-bridge vibration characteristic is analyzed by a computer program when mixed marshalling freight trains traverse 32-meter-span prestressed concrete simple beam bridges. The mechanism that dynamic responses of the bridges are prominent and that empty trains are inclined to derail are derived from the dynamic responses analysis. The analysis indicates that the significant differences of axle loads between heavy vehicles and empty vehicles produce periodic forced loadings of large amplitudes. These periodic loadings cause severe vibration of bridges. In turn, severe vibration of the bridges produces intensive counteraction to empty vehicles. __________ Translated from Journal of Tongji University (Natural Science), 2007, 35(2): 171–175 译自: 同济大学学报(自然科学版)]