Cold-formed thin-walled steel sections are usually used in planar structural systems with insulation on both sides. Due to their small thickness, when exposed to tire, they dissipate heat to the surrounding quickly, leading to rapid temperature increases. Also because they employ planar fire protection and are usually exposed to fire attack from one side, a significant temperature gradient through the cross-section of a thin-walled member can be induced. A temperature gradient may also be present in the width direction because thin-walled members lose heat rapidly to their surroundings. As a result, temperature distributions in a thin-walled steel section can be highly non-uniform under fire conditions. Furthermore, the thermal performance of the steel section will depend on the presence or otherwise of the protective layers, usually made from gypsum boards, which may not always stick to the steel section due to possible integrity failure. In this study, the thermal performance of thin-walled steel channel sections in a planar system under fire attack from one side has been investigated both experimentally and numerically. In the experimental study, fire tests were conducted on eight steel stud panels with different types of steel section, different number of gypsum boards and either with or without interior insulation. The numerical study was performed by first validating the capabilities of a commercially available general finite element program ABAQUS. Afterwards, ABAQUS was used to carry out a parametric study to investigate the thermal performance of steel stud systems with different numbers of gypsum boards on the exposed and unexposed sides and that of cassette systems. Results of these investigations indicate that the thermal performance of cold-formed thin-walled steel channel wall panels are not significantly affected by the type of interior insulation and the shape of the cold-formed thin-walled steel cross-section. Temperatures of the steel section of a steel stud panel system depend primarily on insulation panels on the fire exposed side. A cassette section, which has a wide web (300-400 mm), two flanges and two narrow webs, is an alternative to conventional steel stud to eliminate cross-bracing. The thermal performance of this type of wall system is greatly affected by its layout, i.e. whether the continuous steel sheet is on the fire exposed side or the unexposed side. Temperatures in the steel cassette section are higher if the continuous sheet is on the fire exposed side. (C) 2003 Elsevier Science Ltd. All rights reserved.
