Analysis of Steel Columns in Fire with Varied End Restraints

Steel columns subjected to fire are prone to significant variation of boundary restraints while being exposed to fire loading. This paper presents the effect of end restraints on the behavior of hot rolled steel columns under uniform temperature profile (ISO 834-1: 1999) studied numerically. Nonlinear finite-element analysis was done using ABAQUS. Typical slenderness ratio (39), pre-applied axial load ratio (0.2, 0.4 and 0.6) and pre-applied moment ratio (0.1, 0.15 and 0.2) were considered in the present study. In addition to the above, constant axial restraint ratio (0, 0.2, 0.4 and 0.6) within the range as reported in Broadgate phase-8 fire report (0.1–0.9) and varying rotational restraint ratio (0, 2.81, 5.45 and 20.66) with increase in temperature as observed from Cardington test (1998) are used in the analysis. Based on one hundred and forty four trials done, buckling and critical temperature was plotted to assess the interactive effect of various parameters mentioned above.