Design Method for Buckling Failure of Plate Elements

The compressive stress required to cause initial local buckling of a flat element is related to a “normalized slenderness.” This value is used in a normalized buckling curve, appropriate to the material, to give the normalized buckling stress. Flat elements supported on the two long edges possess postbuckling strength, which is obtained by taking the square root of the normalized initial buckling stress to give an “effective strength.” This “effective strength” replaces the yield strength in the design of columns in which local buckling affects overall flexural buckling, and it is used as the limiting extreme fiber stress in beam-columns. “Effective strength” may be interpreted as an “effective thickness” or, less conveniently as an “effective width.” Uniform and gradient compressive stresses and shear stress are treated. Comparisons are made with current code requirements.