ABSTRACT
ABSTRACT CFS members can be forged into many types of cross sections. Schafer (2006b) suggests that the DSM, a modern design method, is to replace the effective width method when designing CFS members. Bauer (2016) found that the DSM based provisions of SANS 10162-2 may be insufficient to achieve the target reliability provided by the resistance formulation. The objective of this study is to assess the safety levels provided by SANS 10160-1 for CFS compression members. A prequalified C-section is considered for the investigation of the local and global buckling failure modes. Various member lengths are considered for the section. The member is assessed for four ultimate limit-state load combinations as per SANS 10160-1. The considered loads are various ratios of permanent, imposed and wind loads. From a FORM analysis, the global buckling mode yields the lowest reliability levels, ranging from β = 1.78 corresponding to an STR-P load combination with a high permanent load ratio; to β = 2.87 corresponding to an STR load combination with a high ratio of imposed loads. Particularly when a high level of permanent load is present, the low levels of reliability are cause for concern.
