The Impact of Cross Beam on Stresses of Girders in Low Water Bridges

Abstract

Low water bridges are classified to a group of military bridges, most frequently made of materials obtained at their construction site (steel sections and wood). They are characterised by similar structural solutions as civilian bridges, commonly called detour or temporary ones. However, low water bridges are structures that are not expected to enable the conduct of shipping and the runoff of ice floes. The aim of this study is to determine the impact of the number of cross beams and their rigidity as well as assembly connections made on the stress distribution in spans of low water bridges. The carried out numerical analyses (FEM) have shown that either the number of girders or the number of cross beams significantly affect the stress distribution in main girders. Moreover, these analyses have proved that the rigidity of cross beams and the manner of assembly connections execution with the sufficiently rigid wood plate have little effect on the stress distribution in the major structural elements of low water bridges. The analyses have shown, however, a very large impact of the way of modelling assembly connections in a steel grate on the stress distribution in the wood plate.