Direct Strength Method and Continuous Strength Method for Cold-Formed Lean Duplex Stainless Steel Columns

The direct strength method and continuous strength method are gaining increasing acceptance in design of stainless steel columns. This study investigates the applicability of these design methods for coldformed lean duplex stainless steel columns, which is a relatively new high strength material with low nickel content. Available data were collected and compared with design strengths calculated from the direct strength method for stainless steel and carbon steel columns as well as the continuous strength method. It is shown that these design methods are generally conservative to predict the column strengths. The direct strength method for stainless steel using tangent modulus approach to determine the column buckling strength provides accurate predictions, but this method involves iterative process in the calculation. Modified direct strength method for stainless steel using explicit strength method to determine the column buckling strength is proposed in this paper. It is shown that the modified direct strength method is capable of predicting the column strengths accurately with a relatively simple calculation procedure