Influence of rigidity of a flange ridge knot of a double hinged arch on the redistribution of efforts in its elements

The theoretical determination of the actual stiffness of the ridge knot of a steel perforated arch was carried out using the initial parameter method, which made it possible to calculate the stress in the upper reference section of the structure belt. The application of the proposed calculation method makes it possible to determine the rigidity of the bolted flange connection, taking into account its actual operation, and to change it by changing the geometrical parameters of the nodal details, that is, the diameter of the bolts or the thickness of the flanges.It is marked that in the calculation of building constructions an important value has exact determination of boundary conditions of connection of nodal elements, that substantially influences on the redistribution of efforts in the separate elements of constructions on their length and rigidity of knots. Especially it touches of flange bolted joints. Current design rules use idealized schemes of nodal joints, which, according to numerical researches, do not fully correspond to the actual operating conditions of nodal joints and constructions on the whole. For realization of aim of researches, that is, theoretical determination of rigidity of ridge knot of the steel preliminary tense perforated arch, the method of initial parameters is used, which allowed to define theoretical tensions in the supporting cut of fastening upper belt to the ridge knot of arch. Divergence in the values of actual tensions in the cuts of beam and theoretical, calculated according to the current design rules, is explained by the flexibility of the flanged bolted joints, that due to the actions in the knot of bending moment opens up, although in theoretical calculations this joint is accepted by absolutely rigid. Rigidity depends on the thickness of flanges, diameter of bolts, the distances between them, the values of the previous tension of the bolts and external loading. The conclusion is set forth, that the application of the offered methodology of calculation allows to define the rigidity of the bolted flanged joint taking into account its actual work, and which, according to experimental researches and theoretical calculations, differs from the idealized calculation schemes. In addition the proposed methodology allows to change the rigidity of the bolted jont, changing the diameter of the bolts or the thickness of the flanges, and also to use the additional resource of material due to some reduction of the maximum tensions in weak cuts of elements.