system is best known as “steel framing”. The considerable growth in the use of sheathed wall‐studs rather than traditional masonry walls is primarily due to its lightweight and because it is faster to build. In a “steel framing” building the sheathing – usually plywood, gypsum, and/or oriented strain board (OSB) – braces the cold‐formed steel studs under load and has a significant impact on the stability and strength of cold‐formed steel studs.
a) View from outside the building
b) View from inside the building
Figure 1 – Low‐rise building with cold‐formed steel wall stud. Since 1962 the AISI specification has proposed essentially three different methods (sections 2.1 and 2.2) to design sheathed stud walls. The first method was proposed in 1962 (AISI, 1962), the design method was revisited and a new proposal was published in 1980 (AISI, 1980), which remained on the specification until 2004 when it was abandoned in favor of something similar to the 1962 approach (AISI‐S211, 2007). This paper also discusses in section 3 the double fastener spacing, or “2a” rule, which in essence implies that given the possibility of a missed fastener, where fasteners are at spacing (a), one should design for a stud buckling at a length twice the size of the spacing between fasteners, i.e. 2a.
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