Fire resistance design method for restrained stainless steel H-section columns under axial compression

摘要

Considering the material and geometric nonlinearity of restrained axially-compressed stainless steel H-section columns, this paper investigates their behavioural responses during fire exposure via the coupled thermo-mechanical analysis method and finite element models that were established by using ABAQUS. 7 restrained stainless steel H-section columns under axial compression were tested in the ISO-834 standard fire. A numerical simulation analysis was carried out, and the validity and feasibility of the finite element analysis model was proven by the test results. On this basis, a parameter-influencing analysis was performed to determine the main influencing factors of the fire resistance of a restrained axially-compressed stainless steel H-section column. The result shows that the load ratio n, slenderness ratio lambda, axial restraint stiffness ratio beta(l) and rotational restraint stiffness ratio beta(r) are the key factors. Based on existing experimental studies and numerical simulations, an equivalent method of rotational restraint at the ends of a stainless steel column in fire is tentatively presented. A simplified formula, based on the effective length coefficient mu(theta) of restrained axially-compressed stainless steel H-section columns, for calculating the critical temperature is proposed.