Effects of Modeling Parameters on Dynamic Performance of Railway PSC Bridge Girders

Abstract

This study investigated the effects of finite element modeling parameters on the dynamic characteristics and responses of railway prestressed concrete bridge girders. Free vibration analyses using different modeling parameters showed that the natural frequencies increased when an anchorage was included or when the upper flange thickness was kept constant in the modeling. The maximum dynamic responses of the girder at different speeds of two trains [a high-speed train (KTX) and a freight train] were compared using different modeling parameters. Changes in the flange thickness did not have any significant effect on the maximum vertical displacement. However, the maximum acceleration of the girder for the flange modeled with the originally designed varying thickness was higher than that for the flange modeled with the average thickness as a constant. This difference became more significant as the train speed approached the critical speed of resonance. Regardless of whether the anchorage was modeled, no significant change was found in the maximum vertical displacement for both KTX and the freight train. The vertical accelerations for both the trains were generally lower when the anchorage was modeled. Particularly, the vertical acceleration for KTX near its critical speed of resonance showed larger differences among the finite element models.