NUMERICAL ANALYSIS OF COLD-FORMED STEEL BEAMS IN FIRE

摘要

An investigation into the structural behavior of cold formed steel beams commonly used inrnwarehouses and industrial buildings subjected to fire is presented in this paper. A large series ofrnnumerical simulations performed with the finite element program ABAQUS were carried out and thernresults are discussed in this paper. Therefore, in the first phase of this research several experimentalrnfire tests of cold-formed steel beams were undertaken to obtain the failure loads and failure modes ofrnthe beams, in other words, the results needed to validate the developed finite element model. Thernsecond phase of this research involved obviously the development and validation of a suitable finiternelement model in order to simulate the structural response of the beams in fire and subjected torndistortional buckling and lateral-torsional buckling effects. Finally, a parametric analysis was carriedrnout using the validated finite element model with the purpose to investigate numerically the effect ofrnsome parameters such as section geometry, initial applied load on the beam, span and magnitude of therninitial geometric imperfections of the beams on their structural behavior. Some conclusions of thisrnresearch study were that the hollow beams may have an increase of about 50% in the fire resistance,rncomparing to the open beams and that the initial geometric imperfections may cause a significantrnreducing in the critical temperature of the beams in function of the applied loading. They may evenrnreduce by 20% the critical temperature of the beams.