Tomaž Hozjan

BUCKLING OF AN AXIALLY RESTRAINED STEEL COLUMN UNDER FIRE LOADING

Analytical procedure, based on the linearized stability analysis, 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 nonlinear kinematical equations and the nonlinearity of material are considered. The stress strain relation for steel at the elevated temperature and the rules for reduction of material parameters due to increased temperature are taken from European standard EC 3. Theoretical findings are applied in the parametric analysis of a series of Eulers columns subjected to two parametric fires. It is found how the slenderness of the column, the material nonlinearity, the temperature dependence of material parameters, and the stiffness of restraints at supports effect the critical temperature. While these parameters have major influence on the critical temperature, they have no effect on the shape of the buckling mode.

Analytical solution of linear elastic beams cracked in flexure and strengthened with side plates

A new mathematical model and its analytical solution for the analysis of the stress–strain state of a linear elastic beam cracked in flexure and strengthened with plates on its lateral sides is presented. Both the longitudinal and the transversal interactions at the side plate/beam interface are considered. Linear behaviour of the contact connection is assumed. The method is based upon the linearised planar beam theory of Reissner. The weakening of the beam induced by the flexural crack is modelled conventionally as a rotational spring. The suitability of the theory is demonstrated in a case presentation involving the comparison between analytical results of the present beam (one-dimensional) model, the experiments and the numerical results of a full three-dimensional solid model created in the LUSAS finite element analysis software. An excellent agreement between the results is observed and the proposed formulation is found to be accurate and reliable. Finally, the solution is employed in an engineering analysis, discussing the effects of the material and the geometric properties of selected characteristic cases of the observed beams on the static and kinematic quantities, including the boundary conditions of the side plates, the longitudinal and the transversal stiffness of the connection, the size of the cracks, the span of the beam, and the length and the stiffness of the side plates. For the cracked cantilever beam, a substantial effect of any of these parameters is found. In contrast, for the cracked two-span continuous beam, only the effect of the stiffness of the side plates and the effect of the length of the beam spans are noticeable.

Model evaluation of heat and mass transfer in wood exposed to fire

The paper presents sensitivity analysis of coupled heat and moisture transfer model for timber exposed to fire. The objective of the analysis is to discover the non-influential model parameters and the model simplification accordingly. To achieve this, the standardized regression coefficient (SRC) method is introduced to determine the impact of specific permeability of dry timber K, bound water diffusion coefficient

PERFORMANCE-BASED ANALYSIS OF PLANAR STEEL FRAME IN FIRE, The effect of different types of thermal insulation

D_{0}

Fire Analysis of Steel Frames with the use of Artificial Neural Networks

D0, vapour diffusion coefficient

The fire analysis of a steel–concrete side-plated beam

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