EXPERIMENTAL STUDY ON POST-FIRE MECHANICAL PROPERTIES OF HIGH STRENGTH FIRE-RESISTANT STEEL

A series of static tensile tests on high-strength fire-resistant steel such as grades Q460FR, Q420FR, Q345FR after fire were carried out in this study. The stress-strain curves and mechanical parameters of high-strength fire-resistant steel with post-fire temperatures from 200℃ to 800℃ were obtained. After comparing their mechanical properties with those of ordinary structural steels after high-temperature cooling, the coefficient of variation fitting equationthe of yield strength and tensile strength were proposed. It is shown that: the yield strength and tensile strength of high-strength fire-resistant steel with natural cooling after fire have been improved, while the modulus of elasticity is not influenced by exposing to fire. The results of this study can be applied to the assessment of load-bearing performance of fire-resistant steel structures after fire.