Effective width of stiffened cold-formed steel plates

This paper reviews the experimental data available in the literature concerning the effective width concept. The formulae for effective width that are contained in the AISI-68 and the CSA S136-74 specifications are critically discussed in relationship to the experimental data. The effective width is shown to be clearly a function of the actual width, in contrast to the constant value implied by the CSA S136-74 specification. A formula of the type used in the AISI-68 specification is found to be very suitable. It provides for reduced strength due to interactive effects in plates of moderate width to thickness ratios and places a limiting value on the effective width of very thin plates.A new design rule, of the simple form Be = 2 − 1/B, is proposed as an appropriate guide for the design of stiffened cold-formed steel plates.