Review of Design Thickness Requirements for ASTM A500 HSS in Canada

The principal options for cold-formed hollow structural sections (HSS) in Canada are product manufactured to CSA G40 and ASTM A500. For CSA G40 HSS, a design wall thickness equal to the nominal thickness of the section is used for design; however, for ASTM A500 HSS, the Canadian Institute of Steel Construction (CISC) stipulates that a design wall thickness equal to 0.9 times the nominal thickness must be used. The design wall thickness requirement for ASTM A500 HSS was first introduced in 1974 and has been unchanged for nearly a half century. Over that same time period, methods of HSS production, material grades, sizes, and quality control procedures have evolved. The primary objective of this research is to conduct a systematic review of the design thickness requirement for ASTM A500 HSS in Canada. This review is expected to provide insight that will help increase the economy of structures (by reducing material requirements), encourage the use of ASTM A500 HSS, and improve the competitiveness of domestically produced steel.