Cold-formed steel members maintain a constant thickness around their cross-section, whereas hot-rolled shapes typically exhibit tapering or fillets. History of AISI design standards ĭesign standards for hot-rolled steel (see structural steel) were adopted in 1930s, but were not applicable to cold–formed sections because of their relatively thin steel walls which were susceptible to buckling. A site observation during this renovation confirmed that "these joists from the 'roaring twenties' are still supporting loads, over 80 years later!" In the 1940s, Lustron Homes built and sold almost 2500 steel-framed homes, with the framing, finishes, cabinets and furniture made from cold-formed steel.
Greene engineered a recent renovation to the structure and said that for the most part, the joists are still performing well. According to Chuck Greene, P.E., of Nolen Frisa Associates, the joists were adequate to carry the initial loads and spans, based on current analysis techniques. The walls were load bearing masonry, but the floor system was framed with double back-to-back cold-formed steel lipped channels. One of the first documented uses of cold-formed steel as a building material is the Virginia Baptist Hospital, constructed around 1925 in Lynchburg, Virginia. In the 1920s and 1930s, acceptance of cold-formed steel as a construction material was still limited because there was no adequate design standard and limited information on material use in building codes. The use of cold-formed steel members in building construction began in the 1850s in both the United States and Great Britain. 9 Hot-rolled versus cold-rolled steel and the influence of annealing.8.2 Connectors and fasteners in framing.7.1 Minimum material thickness recommended for welding connections.New design example to illustrate the design of cold-formed steel floor and axial load-bearing wall framing with ledger framing, andĪddition of Appendix L, which provides a complete listing of Technical Notes available from the Cold-Formed Steel Engineers Institute (CFSEI).ĪISI’s codes and standards work is conducted under the Construction Market Council of the Steel Market Development Institute (SMDI), a business unit of AISI, which oversees the industry’s investment in advancing the competitive use of steel by meeting the demands of the marketplace.įor more information on SMDI’s Construction Market program, visit or 4 Common section profiles and applications Modification of an alternative parapet design using cantilevering HSS posts to reflect an approach with more flexibility for field installation, Modification of the slide clip detail for connecting wind-bearing studs that is more typically used in modern construction, Inclusion of distortional buckling calculations in the design example of a wind-bearing infill wall with an unsheathed design approach, Use of load combination factors as required by ASCE/SEI 7-10, Minimum Design Loads for Buildings and Other Structures, Revised design examples that conform to the latest cold-formed steel framing design standards, including AISI S100-12 and AISI S240-15, North American Standard for Cold-Formed Steel Structural Framing, 2015 Edition, They are based on AISI S100-12 – North American Specification for the Design of Cold-Formed Steel Structural Members, 2012 Edition. This issue of the design guide updates the 2007 edition and is available for purchase at the AISI Steel Store, The design examples featured in AISI D110-16 illustrate both screwed and welded connection details. The guide provides a general review of basic structural principles and five comprehensive design examples that cover wind-bearing and axial load-bearing stud walls and joists. The American Iron and Steel Institute (AISI) published AISI D110-16 – Cold-Formed Steel Framing Design Guide, 2016 Edition, to assist practicing structural engineers in designing cold-formed steel framing systems.