Features of the work of reinforced concrete arches with adjustment of effort under repeated loads

In two-hinged arches, by adjusting the tightening force, it is possible to reduce the maximum values of bending moments in cross-sections under certain loads and dimensions of the structure. Solid two-hinged arches can be manufactured both at factories of reinforced concrete structures and directly at construction sites, depending on the size of the structure, the possibility of transportation, their number and other factors. Such arches are used in constructions covering industrial and public buildings, bridge structures, spatial coverings of buildings (shell diaphragms). In the process of operation, arches as a part of coverings in industrial and civil buildings and structures can be subjected to repeated loads, sometimes overloading and damage, which significantly affect the stress-deformed state of the cross-sections of the arch and tension. In two-hinged arches, there can be a redistribution of forces between the upper belt of the arch and the tightening, which affects their strength and stiffness. The work of two-hinged reinforced concrete arches was experimentally investigated, which makes it possible to investigate the features of the stress-strain state of the belt sections and the nature of the redistribution of arch forces between the upper belt and the tension, the development of deflections and cracks under one-time and repeated short-term static loads. As a result of the formation and development of cracks, the growth of plastic deformations in concrete, the stress-strain state changes and there is a redistribution of internal forces in the cross-sections of the arch, the rigidity of the reinforced concrete belt of the arch decreases and it works as an elastic element. The methodology for calculating the internal forces of two-hinged reinforced concrete arches is presented, taking into account the redistribution of forces during repeated loads. The proposed method will make it possible to more reliably design reinforced concrete arched structures, namely to reduce the moment of cracking of the stretched concrete zone, the deflection of the structure without reducing the bearing capacity of arched structures.