The Use of Box Cross‐Sections for Railway Bridges with Encased Steel Girders

Abstract

ABSTRACTIn the area of railway bridges, the use of the superstructure created by reinforced concrete deck with encased steel beams is often a preferred alternative for small spans. Despite of well‐known disadvantages, this type of bridges is still preferred by railway authorities because of their high stiffness and small construction depth. Research on new bridges of this concept is focused in particular on optimization and saving material. The article presents a follow‐up study focused on the optimization and efficiency of the use of existing database of box girders for bridging small spans. The main dimensions of the bridges in the study were based on the already published study. As box cross‐sections, commercially developed and produced beams were utilized. Because of high combined bending and torsion resistance, and advanced fire resistance, as well, they are primarily applied in the building structures. They have not been able to find use in bridges, especially due to higher prices per unit weight. However, similar beams can be produced routinely, so the study can served to point out the possible benefits of applying similarly shaped build‐up cross‐sections. In addition to the material consumption, the influence on stiffness of the bridge cross‐section is also discussed.