Response of steel beam-columns exposed to fire

Steel beams when exposed to fire develop significant restraint forces and often behave as beam-columns. The response Of Such restrained steel beams under fire depends oil many factors including fire scenario, load level, degree of restraint at the supports, and high-temperature properties of steel. A set of numerical studies, using finite element computer program ANSYS, is carried Out to Study the fire response of steel beam-columns under realistic fire, load and restraint scenarios. The finite element model is validated against experimental data, and the importance of high-temperature creep on the fire response of steel beam-columns is illustrated. The validated model is used to carry out a set of parametric studies. Results from the parametric studies indicate that fire scenario, load level, degree of end-restraint and high-temperature creel have significant influence on the behavior of beams under fire conditions. The type of fire scenario plays a critical role in determining the Fire response of the laterally-unrestrained steel beam within a space subframe. Increased load level leads to higher catenary forces resulting in lower fire resistance. Rotational restraint enhances the fire resistance of a laterally-unrestrained steel beam, while the axial restraint has detrimental effect on fire resistance. (C) 2008 Elsevier Ltd. All rights reserved.