STRENGTH OF SLOPING SECTION OF PRESTRESSED FLEXURAL ELEMENTS WITH HIGH-STRENGTH AT- 1200 CLASS STEEL REINFORCE
The article presents the trial results of the thermo-mechanical reinforced 30HGS2(30XrC2)grade At-1200steel, one of the best high-strength Russian reinforced steels, on the basis of the first time ever rolled assortment test lots (10 ... 32 mm). This article gives a generalized assessment of physical, mechanical and service properties for the given grade of reinforced steel in as-delivered condition and after prestressing. It reflects the research data of At-1200 reinforced steel prestressing influence on strength and deformation properties. An analytical dependence for the initial and "reinforced" diagrams approximation of deformed steel is offered. The following methods are developed according to the results of experimental and theoretical studies of the trial flexural members with At-1200 reinforced steel during preoperational stage of reinforcement tension release, under load and at simulation of load phase. The first one is a calculation method of the longitudinal crack resistance of the end sections' beam elements at reinforcement tension release. And another one is a calculation method of the standard cross-sections using real rebar load-elongation diagram, method of calculating the strength of sloping sections. It is proved that standard cross-sections' strength of prestressed flexural elements increases due to identified strengthening effect of the reinforced steel. The possibility of rational use of innovative steel class At1200 as a strained fixture of curved elements is justified.