Transition Zones of Steel Bridges as Hotspots for Track Buckling

Abstract

Open deck steel bridges are characterized by the direct connection of transoms to the bridge girders. The expansion of steel girders due to thermal loads is transmitted by the fastening system to the track in the transition zones as compressive loads. Adding compressive thermal loads in continuously welded rails (CWRs) and train braking can significantly increase track buckling potential in the transition zones of open deck bridges. This paper treats the static and dynamic track buckling in the transition zones of open deck steel bridges using a multibody train-track dynamic model and a three-dimensional finite-element track model. Considering resilient fasteners and zero toe load (ZTL) fasteners, six fastening profiles are defined. For the train-track interaction, normal and severe braking of wheels is considered. Based on the results, it is concluded that dynamic buckling temperature depends chiefly on steel girder temperature and location of misalignment. Using a combination of resilient fasteners and ZTLs can be an effective way to enhance the performance of CWR tracks on open deck steel bridges.