Construction Loads of the Flexible Arch Bridges

A characteristic feature of soil-steel structures is that, unlike in typical bridges, the backfill and the carriageway pavement with its foundation play a major role in bearing loads. In the soil-steel structure model one can distinguish two structural subsystems: the shell made of corrugated plates and the backfill with the pavement layers. The interactions between the subsystems are modelled as interfacial interactions, i.e. forces normal and tangent to the surface of the shell. This is a static condition of the consistency of the mutual interactions between the surrounding earth and the shell, considering that slip can arise at the interface between the subsystems. This paper presents an algorithm for determining the internal forces in the shell on the basis of the unit strains in the corrugated plates and subsequently, the interfacial interactions. The effects of loads arising during the construction of a soil-steel bridge when, e.g., construction machines drive over the structure, are taken into account in the analysis of the internal forces in the shell and in the surrounding earth. During construction the forces in the shell are usually many times greater than the ones generated by service loads. Thus the analytical results presented in this paper provide the basis for predicting the behaviour of the soil medium under operational loads.