Effect of static deflection of long-span bridges due to temperature variation on safety and riding comfort of running train

초록

According to a recent trend of speed-up of rail traffic, the construction of long-span bridges, such as extra-dosed bridges and multi-span arches, is in a growing trend in Korea. Temperature is a very important factor in the design of bridges, especially of these long-span bridges. Until now, the temperature load was considered only in checking the stress of bridge members. However, large deflection of bridge superstructure makes worse the long-wave track irregularity, and may aggravate the running safety of train or the ride comfort of passengers. In general, the longer is the span length, the bigger becomes the effect of temperature on the deflection of bridge superstructure. So it is required in the design of the long-span bridges, to check the effect of temperature on the running safety and ride comfort. This study is, therefore, aimed to investigate this temperature effect on the long span bridges constructing in Korea through the following procedures. Firstly, the deflection of bridge due to temperature variation has been calculated by FE analysis for 4 different load cases. Secondly, evaluated is the track irregularity caused by this thermal deflection of bridge. Finally the running safety and the ride comfort are assessed by the dynamic analysis of coupled train-track system considering interaction. For this, the criteria of running safety and ride comfort have been set based on international codes. Through the parametric study for several types of long span bridges, it is known that the train velocity and the bridge type(main material) are the key factors on running safety and ride comfort, and that the condition of concrete curing can make a significant influence on the train behaviors.