Fire performance of gypsum-sheathed cold-formed steel walls with rectangular section studs: Fid-Bau Portal

Fire performance of gypsum-sheathed cold-formed steel walls with rectangular section studs

Liu, Kang / Chen, Wei / Ye, Jihong / Jiang, Jian

Abstract This study conducted axial compression experiment of one full-scale CFS wall at ambient temperature and four full-scale fire experiments of CFS walls with two initial load ratios of 0.27 and 0.85. Specimens were sheathed with double layers of gypsum plasterboard, rock wool was the cavity insulation and the wall studs had rectangular cross sections. A finite element model was used to optimize the arrangement of rock wool cavity insulation for the CFS walls. The results showed that the failure mode changed from local buckling of the hot flange under a load ratio of 0.27 to local buckling of the whole stud section under a load ratio of 0.85. The fire resistance time of the specimen without rock wool insulation in the stud cavity was 7 min longer than that of the specimen with rock wool insulation. This was attributed to the thermal radiation effect of the stud cavities, which delayed the increase in hot flange temperature and improved the fire resistance time of the CFS walls. Thus, for CFS walls with rock wool-insulated cavities, the stud cavity configuration was more reasonable without than with rock wool insulation. When the axial thermal expansion load was considered, the load on the wall studs increased by a maximum of 43.3 kN per stud. In addition, for CFS walls with low load ratios of 0.27, the wall studs near the face-layer board joints tended to buckle first.

Highlights • Fire experiments were conducted on four full-scale CFS walls with rectangular section studs. • Illustrated the benefits of using rectangular section studs in cavity insulated CFS walls. • Under low load ratios, the wall studs near the face layer board joints tended to buckle first. • Under a high load ratio the failure mode of the CFS wall was changed.