Explicit Approach to Design of Stainless Steel Columns

The paper describes a design procedure for stainless-steel columns failing by flexural buckling. In the approach, the stress-strain curve is assumed to be expressed as a Ramberg-Osgood curve, defined in terms of the initial modulus (E₀), the 0.2% proof stress (σ_0.2), and the parameter n. It is shown that the column curve can be described in terms of the Ramberg-Osgood parameters by adopting a Perry curve as the basic strength curve, and expressing the imperfection parameter in terms of E₀, σ_0.2, and n. By using a Perry curve, the design procedure is explicit. This contrasts with the iterative approach described in the ASCE load and resistance factor design (LRFD) specification for the design of cold-formed stainless steel structural members. The proposed strength curves are compared with those from tests on stainless steel columns. It is shown that the coefficient of variation of the ratio of test strength to design strength is lower using the proposed design approach than when using the ASCE specification; thus, the proposed approach is more accurate than that described in the ASCE specification. It is also more efficient because it is explicit. Using the comparison with test results, the resistance factor to be used with the proposed design procedure is derived.