Limit states design of HSS columns

Abstract

Hollow structural sections (HSS) have come into increasing usage for structural purposes over the past number of years. There are several reasons for this development, in particular, the advantages of such shapes from an architectural viewpoint, the strength inherent in a closed cross section, corrosion stability, and ease of maintenance. Due to their shape, the members are particularly suited for use as columns.This paper presents a review of typical HSS production methods used throughout the world today, with emphasis on the effect of several important parameters that vary with the production process. Following a general discussion of column strength theory and its application to HSS columns, the development of limit states design procedures for compression members is evaluated. Special attention is paid to the requirements of the standard CSA S16.1-1974, and the studies that led to these rules.Outlining briefly the philosophy of full-scale column testing and typical procedures that are followed in such work, the ensuing portions of the paper present detailed data from experimental and theoretical studies on Canadian-produced HSS sections. Column tests conducted on heat-treated shapes are compared to other data from similar tests on columns produced by a variety of manufacturing processes. It was generally found that the heat-treated shapes performed somewhat better than the cold-formed columns, considered as a whole, and that within the cold-formed data there was considerable variation between manufacturers. Comparison with data from column tests conducted in Japan and in Europe revealed that the Canadian shapes tended to fall within the upper portions of the data band.In closing, preliminary recommendations are presented for the evaluation of the strength of various manufactured HSS members in limit states design.