Load rate of the circumferential sector of soil-steel bridge structures

In order to calculate the parameters soil-steel structure, a special software based on a 2D model is used. The concentrated forces of a bridge roadway generated by vehicles are being related in this model to a selected sector based on Boussinesq’s theory. This theory, however, does not fully confirm the work effect (internal forces) of soil-steel structures as flexible structures cooperating with soil in carrying external loads. The effectiveness of this theory was estimated according to the 3D model built out of FEM elements. For this reason a comparison algorithm was constructed based on the influence function of internal forces for a selected strip of steel shell. The analysis showed the influence of general parameters of the bridge (width, span) on internal forces being neglected in developing the guidelines for such bridges. The parametric analysis given in this paper refers to a completed construction of a classical soil-steel bridge built in Szczytna. As variable characteristics of the object we assume: thickness of backfill, shell span, haunch radius, kind of steel corrugation as well as sheet thickness of the shell types applied. The analysis proved that some of them essentially influence the system of internal forces. The results of analysis of geometric parameters of the steel shell indicate the possibility (theoretical) of such a modification of the structures that allows reduction in steel usage.