The Influence of Heating-up and Rapid Cooling on an Axially Restrained Steel Column in Fire

Abstract

Abstract-Heating-up and rapid cooling by spray water had a large impact on the mechanics and deformation behavior for an axially restrained steel column. During heating, the axial force of the restrained steel columns increased in linearly. During rapid cooling, its axial force rapidly decreased until zero, and then it increased until the peak, and the max axial force was about 16% larger than that produced at heating, and its max bending moment was about 20% lager than that produced at heating. Axially restrained stiffness had a negative affection for its bearing capacity. When the axial stiffness ratio was less than 0.05, the buckling and failure temperature was relatively close, but when it was more than 0.05, there was a significant difference between them. Rotationally restrained stiffness played a beneficial role in its stable bearing capacity in fire. When its rotational stiffness ratio was less than 0.4, the rotational restrained stiffness had a large beneficial effect on its stability, but when the rotational stiffness ratio was more than 0.4, this beneficial effect was relatively small.