Fire resistance behaviour of non-load bearing LSF walls with restrained thermal elongation

In this research study, based on suitable and rational thermal and sequentially coupled structural FE (finite element) analyses, the fire resistance behaviour and FRLs (fire resistance levels) of non-load bearing LSF (light gauge steel framed) walls with restrained thermal elongation were deeply analysed. The FE analysis results confirmed that CFS (cold-formed steel) channel studs of the mentioned walls collapsed prematurely due to additional compression loads caused by the effects of fire and the thermal elongation restraints at stud ends, which led to the reduced FRLs of these walls. Besides, the wall height and the clearance between the stud ends and rigid floors were shown as having significant effects on the FRLs of non-load bearing LSF walls with restrained thermal elongation. In contrast, the effects of the thickness and depth of CFS channel studs and cavity insulation were inconsiderable. Finally, a simplified and reliable design equation and some recommendations were proposed for some types of non-load bearing fire-rated LSF walls commonly used in Australia. This paper presents details of this study, including its analyses, outcomes, and proposals. • Investigated non-load bearing light gauge steel framed walls with restrained thermal elongation. • The FRLs of these walls can be reduced due to the thermal elongation restraints at stud ends. • The wall height and clearance between the stud ends and rigid floors could significantly affect the FRLs. • Effects of thickness and depth of studs and cavity insulation on the FRLs were minor. • Proposed a suitable design equation and recommendations.