Critical Temperature of Load Bearing LSF Walls Under Fire

Abstract

AbstractLight Steel Frame (LSF) walls are widely used in building structures, used as partition walls and load bearing walls. The LSF is usually protected by layers of homogeneous plates or composite plates, with or without insulation materials in the cavity. This investigation presents the experimental and the simulation results of composite LSF walls in reduced scale and full scale, based on variable load levels (20 to 80%). The numerical model is validated with experimental results, at reduced and full scale, both at room temperature and under fire conditions. This modelling technique can follow the thermal and mechanical degradation of the protection layers of the LSF wall and determine the fire rating for load (R) and insulation (I). The fire resistance (R) decreases with the increase of the load level, being the critical temperature of the steel structure presented by the maximum temperature of the Hot Flange (HF). A new proposal is presented for the critical temperature of the LSF, based on the maximum temperature of the LSF during the fire. The insulation ability is also predicted for different protection materials. Relevant conclusions are presented to increase the insulation ability of LSF walls.