Basis of force and deformation-force resistance of reinforced concrete at the complex stress-strain state

Abstract

World practice shows that the volumes of using monolith and prefab- ricated reinforced concrete are increasing, and in the coming decades they will remain the main structural material. Therefore, it is obvious that the effective using of reinforced concrete, is possible with the presence of reliable, accurate and economical calculation methods. Thereby, much attention is paid towards the development of the theory of reinforced concrete. The experience of designing, construction and exploitation of span re- inforced concrete structures shows that, practically, all of them work at com- plex stress-strain state. At the same time, the researchers pay much more at- tention to the calculation of strength, deformability and crack-resistance of el- ements in normal sections, than to the calculation of their areas near supports, including the inclined sections. Besides, a significant number of span reinforced concrete elements, is subjected to the action of low-cycle loads. They lead to such specific features of concrete work as nonlinearity of deformation, micro cracking, accumulation of residual deformations, low-cycle fatigue (fatigue damage), decompaction of concrete etc. The results of the research show that the destruction of structure under the action of low-cycle loads occurs at the smaller stresses, than the de- struction of structure under the action of short duration static load.