ASSESSMENT OF STRAIN & THERMAL HARDENING EFFECT OF REINFORCED STEEL At-1200 (At-VII) DURING PRESTRESSING
Cooperative interaction of ”load+time+temperature” leads to changes in physical and mechanical properties and in stress-deformation diagram for steel as a consequence of the strain-thermal hardening and rheological processes. In this paper, the mechanism of this interaction was investigated in terms of a high-strength reinforced steel 30HGS2 of 1200 At (At-VII) class. It was established experimentally that during prestressing a significant increase of resistance characteristics was observed σ <sub>si </sub>(σ <sub>0,05</sub>; σ <sub>0,1</sub>; σ <sub>0,2 </sub>etc.) which became small plastic deformation. The proposed assesement method of the strain-thermal hardening of steel at a temperature approximation of the deformation diagram through a multi-shop (spline) interpolation is universal and can be used to account for the stress-strain state of structural elements in the strength calculations.