Study on Short Span Deck Bridges with Encased Steel Beams

A study focusing on optimization and efficiency of relatively common solution for small span railway bridges is presented. The superstructure of the bridges is created by reinforced concrete deck with encased steel beams. Especially, flexural behaviour was analysed in the study. Actual bridge cross-sections as well as spans were taken into account. Actions according to new European codes were implemented. Usually, simplified uniform transverse redistribution of load for every one of encased steel girders across bridge cross-sections is practised in global analysis. As concrete slab and steel beams are composed together through encasement into steel concrete composite deck, its real behaviour is strongly influenced by the plate effects. Simplified procedures were compared to the models developed by finite analyses. Different types of steel cross sections have been analysed. Particularly, hot-rolled and built-up steel beams are compared. Moreover, unsymmetrical I-shaped and upside-down T-shaped welded steel sections were investigated. In addition, optimisation aspects based on material consumption as criterion would be presented. Finally, the influence of deck cantilever and cornice on flexural behaviour would be studied.