Influence of snow loading character on optimal lattice`s geometric shape of the combined arch system

Abstract

In the article, the authors investigate the question of determining of the lattice made from flexible elements geometric share in a combined arch system proceeding from the condition of its operability and the minimum of the structure material consumption. This question is supposed to be solved with the help of the lattice geometric shape, without using the elements preliminary tension at this stage of the study. Evenly distributed load throughout the span (constant load with the snow load distributed along two triangles with peaks on the supports and zero values in the middle, because this combination of loads can cause a compression force in some elements of the flexible grating) is accepted as a load for determining the lattice geometry. The investigations carried out by the authors have shown that the optimal lattice shape depends not only on the ratio of the constant and snow loads, but also on the upper belt panels number. At what, the snow load according to the scheme of two triangles has determining value, in comparison with the snow load evenly distributed in half of the span. The obtained results of the investigation make possible to designate the combined arch system's lattice geometric share, taking into account the given ratio of constant and time loads in such a way that all flexible lattice's elements will work on tension and the material consumption of the structure will be the smallest.