Lateral torsional buckling of steel i beams in case of fire: experimental evaluation

In this paper, experimental tests on lateral torsional buckling of steel I Beams under fire conditions are presented. The beam, spans varies from 0.5 to 6.5 [m] length and the temperature was risen up to 600 [ºC]. The initial conditions of the steel beams were measured. The residual stress state was characterized by the hole drilling method, using specific strain gauges, The geometric imperfections was measured by means of a laser beam and the cross section of the beams was dimensionally controlled. The methodology to the thermo-mechanical load was first heat the beam and let it expand for controlling the mechanical load position, and finally increase the load step by step. The aim of this work is to validate the proposal for lateral torsional buckling design resistance suggested in ref.[1] based on numerical results. A set of experimental results• are presented, relating the collapse load with the mid span movement of the beam cross section, when submitted to concentrated moments at the ends and to a uniform distributed load, duo to the ceramic mat, the insulation material weight and the self weight of the beams