Effects Of Wheel Defects On Dynamic Track Buckling In Transition Zones Of Open-Deck Steel Bridges

Track buckling potential can be higher in the transition zones of steel bridges due to the combination of contact loads and large compressive forces present in this region because of rail and bridge thermal loads. Wheel-rail contact loads are also magnified due to wheel defects, which has not been addressed before in the literature. The aim of this paper is to have an in-depth investigation of the effects of wheel defects on dynamic track buckling in the transition zones of open-deck steel bridges by employing a multibody train-track dynamic model and a three-dimensional (3D) finite-element track model. Various amplitudes of wheel defects as well as normal and severe braking scenarios are simulated. Because the magnitude of bridge thermal loads in the transition zones is determined by the longitudinal track-bridge interaction, three fastening profiles between the track and the bridge are introduced using resilient and zero toe load (ZTL) fasteners. Based on the results, it is concluded that wheel defects can have a significant effect on dynamic track buckling. Dynamic track buckling temperature can drop by 33% compared to the static track buckling of open track, depending on the amplitude of wheel defect, type of the wagon wheel brake, and girder temperature. Further experimental tests are required to evaluate the applicability of mitigation methods to avoid track buckling in the transition zones, such as using various shapes of sleepers in this zone.