An analytical procedure is presented for the determination of the buckling load and the buckling temperature of a straight, geometrically perfect, axially loaded steel column subjected to an increasing temperature simulating fire conditions. The non-linearity of material at high temperatures is considered. The stress-strain relations and the thermal parameters are taken from European standard EC 3. The proposed theoretical model is applied in the parametric analysis of a series of Euler's columns subjected to two parametric fires. It is found how the slenderness of the column, the material non-linearity, the temperature dependence of material parameters and the stiffness of restraints at supports effect the critical temperature.
COBISS.SI-ID: 5405537
The paper investigates the effects of slip and moisture transfer on the behaviour of a planar steel-concrete composite beam subject to fire conditions. The moisture and the heat transfer is assumed to be governed by a coupled problem, while the mechanical behaviour accounting for slip between layers is described by strain-based beam finite elements. The fire analysis is perfomed in two separate steps, of which the moisture and heat transfer analysis is performed first, followed by the mechanical analysis. The present novel finite-element formulation proves to be appropriate for the thermo-mechanical analysis of frame-like structures, as it is robust, reliable and accurate.
COBISS.SI-ID: 5154913
A mathematical model for structural behavior of timber columns under fire has been proposed. The semi-analytical study has been carried out for evaluating the load-carrying capacity of timber columns exposed to fire. Emphasis is given to buckling loads. A parametric study has been performed showing the influence of the slenderness ratio, the load level, and the water content on the buckling load of timber columns. The results of this preliminary study show that the present semi-analytical method is conservative compared to the two simplified calculation methods offered by Eurocode 5 if the transfer of water is neglected, while, on the other hand, the results agree well for a water content of 12%. Moreover, for higher water contents, the present semi-analytical model is non-conservative compared to the Eurocode 5 methods.
COBISS.SI-ID: 5504097