The influence of lateral bending restrain in numerical and experimental evaluation of lateral buckling resistance design moment of steel I beams at elevated temperatures Conference Paper uri icon


  • The numerical and experimental determination of the buckling design moment of steel I beams is influenced by the type of support and load restrain during the mechanical and thermal load. As a result of beam temperature rise the axial movement will be allowed and the type of load and support restrain will be compared from fully to unrestrained state. For this study a simple supported beam is bent about its axis of greatest flexural rigidity. Taking into account the geometric and material imperfections, the beam may twist before it reaches its strength limit state. This flexural stability limit state is most commonly referred to as lateral torsional buckllng of a beam. The twisting af the beam Occurs when the compression flange becomes unstable as a result of being subjected to flexural induced axial stresses. The design rules in Eurocode 3 related to design of steel structures in fire conditions presents their expressions as a function of the type of support and load. A particular attention will be paid to the type of experimental support and to the numerical finite element model used. The aim of this work is to investigate the value of the effective buckling length of steel 1 beam under the mentioned conditions. A relation between the beam buckling resistance and the lateral bending stiffness will be presented.

publication date

  • January 1, 2001