Resumen de Cold-formed steel portal frames in fire: full-scale testing and finite element analysis
R.P.D. Johnston, J.B.P. Lim, Y. Xu, M. Sonebi, C.G. Armstrong, H.H. Lau, C. Switzer, C.C. Mei
A full-scale, non-uniform natural fi re test on a cold-formed steel portal frame building is described. The results of the fi re test are used to validate a non-linear, elasto-plastic, fi nite element shell idealisation, for the purposes of later forming the basis of a performance-based design approach for cold-formed steel portal frames at elevated temperatures. The test building had a span of 8m, height-to-eaves of 2.2m, length of 10m, with a frame spacing of 2.5m. The member and connections of the frame were constructed entirely from coldformed steel and the eaves and apex joints were classifi ed as semi-rigid.
In order to reduce the infl uence of diaphragm action, the cladding was detailed to act independently from the frames. The frame collapsed with an eventual inwards asymmetrical collapse mechanism at 714°C, with collapse being due to member buckling rather than failure of the screws or joints. The collapse temperature predicted using the shell idealisation was 682°C, with a deformed shape similar to that observed in the fi re test.
