ABSTRACT

The paper presents a semi-analytical procedure for a determination of the buckling load and the critical temperature of a straight, axially loaded steel column subjected to an increasing temperature simulating fire conditions. The main novelty is in consideration of explicitly modeled viscous creep, which is combined with two stress-strain relationships for structural steel. For description of viscous creep strains Harmathy’s (1967) explicit model of viscous creep, with parameters for a structural steel grade S355, is employed. A uniform, yet non-stationary temperature field in the column is assumed. The influence of different mechanical loads, heating regimes, boundary conditions and viscous creep of steel on the buckling of steel column, are studied. It is observed that material models containing viscous creep are time dependent. Parametric study reveals, that the critical temperatures and time, calculated with explicitly considered viscous creep, are greater than those calculated without inclusion of viscous creep in the material model.