Low-cycle fatigue mashing behaviours of HTRB630 high-strength steel exposed to high temperatures

The tensile test and low-cycle fatigue test of HTRB630 high-strength steel bars after high-temperature exposure were investigated. Based on the plastic strain energy density theory of mashing behaviours, the values of parameters K and n in the Ramberg–Osgood stress–strain relationship were obtained. The Coffin–Manson model was modified for further modelling of specimens exposed to different temperatures. A fitted formula for the relationship between the plastic strain energy density and fatigue life of HTRB630 high-strength steel bar specimens was established. The parameters obtained in this study can provide a reference for further investigation of the seismic performance of HTRB630 steel bars reinforced concrete structures after exposure to high temperatures.