Effective Widths of Unstiffened Elements with Stress Gradient

Current American design provisions treat unstiffened elements under stress gradients as if they were uniformly compressed for effective width calculations. Australian, British, and European design provisions allow accurate calculation of the elastic buckling coefficient, however, the same effective width equation for compressed elements is used for elements with stress gradients. In all cases, the design provisions produce conservative bending capacities for sections containing unstiffened elements under stress gradients. This paper presents a design method for calculating the effective width of these elements, based on plate test results of unstiffened elements under strain gradients varying from pure compression to pure bending. It is shown that both elastic and plastic effective widths may be derived from the test results, and effective width methods based on both principles may be used for design.