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 si (σ 0,05; σ 0,1; σ 0,2 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.