The Parametric Analysis And Simulation For Lateral-torsional Buckling Of Steel Girders With Corrugated Webs In Fire Conditions

Corrugated webs girder has thinner web and no transverse stiffener compared to steel girders with plated webs, so the steel quantity and installation cost of steel girder with corrugated webs is reduced. Nevertheless, its bearing capacity is not decreased. As a new form of steel beams with good economy and mechanical properties, corrugated web steel beams is gradually being knowed and applied by engineer. The poor fire-resistance ability is the main weakness of steel structure. With the extensive use of corrugated web beams, a thorough study of the fire-resistance on corrugated webs girder has great theoretical significance and practical value.Based on the numerical calculation of finite element software ANSYS, lateral torsion-flexure buckling resistance of steel girders with corrugated web in elevated temperature was investigated, and its property was compared with steel girders with plated webs. Meanwhile, the effect of geometric parameter, such as the web thickness, corrugation configuration and so on for lateral torsion-flexure buckling resistance of steel girders with corrugated web in nomal temperature was also analyzed in detail.In normal temperature, lateral torsional buckling performance of steel girders with corrugated webs and plated web steel girders with an equivalent thickness under uniform bending were investigated, and their lateral torsion-flexure buckling critical moments were numerically determined. By comparing the critical bending moment, the bearing capacity of girder with corrugated webs was studied. Simultaneously, the influence of the web thickness and corrugation configuration to the critical moments was analyzed detailedly. It was concluded from the numerical analysis that resistance to lateral torsion-flexure buckling of such girders was 10% to 30% higher than the resistance of plate girders with traditional plane webs to lateral buckling, and tilted angle in corrugation and numbers of corrugation have a more significant effect on the value of the critical moment. The parameter contained load rate, initial imperfections, load types have an effect on critical temperature of corrugated webs beams in evenly distributed temperature field. Critical temperature of corrugated webs beams subjected to uniform moments, and concentrated loads at midspan were computed, and it is approximately equal to plated web girders'. However, when distributed load acted on top flange of corrugated webs beam, critical temperature was higher than girder with plated webs.The effect of temperature gradient and initial imperfections on critical temperature of corrugated webs beams in temperature field with temperature gradient was analyzed in detail. When temperature gradient is samll, lateral torsional buckling failure occured in corrugated web beam, however, when temperature gradient is larger, the mode of failure of corrugated web steel beams transformed into bending damage. But temperature gradient has no effect on failure mode of plated web girders, and its failure mode is always lateral torsional buckling failure.