Critical temperature of laterally unrestrained steel plate girders with slender section

Abstract

The results of experimental research and numerical calculations pertaining to the determination of critical temperature value of steel plate girders of slender cross section subjected to lateral torsional buckling are presented in this paper. The experiments conducted in natural scale have been applied to validate the computer model prepared in the environment of ABAQUS computer code. The scope of analysis encompassed mass manufactured plate girders of the IKS type and individually designed girders. Considered components of class 4 cross section were characterized by a high total section height to flange width ratio of 3 to 5.2. Five different load levels, two steel grades and two beam loading schemes have been considered during simulations performed. Based on the results of conducted calculations a simplified method to determine the critical temperature value for the considered class of elements has been formulated. The critical temperature results obtained using this method have been compared against the results of experimental research and results determined using analytical methods. It has been shown that the proposed method assures sufficient accuracy. The influence of relative slenderness, load level and residual stresses on the forecast critical temperature value has been discussed.