Local and Overall Buckling of Cold-Formed Members

The combined effects of local buckling, overall column buckling, and nonuniform material properties in compression members are studied. The results are given for 34 tests on two types of columns, one with local buckling occurring in elements supported along both longitudinal edges, and one with local buckling occurring in elements along only one longitudinal edge. Based on these tests, an analytical approach is presented for predicting the ultimate strength of columns subject to the factors just mentioned. Column buckling is accounted for by means of the tangent modulus concept and post-buckling behavior of plate elements by utilizing the effective width expression developed by the third writer. A simpler approximation of the analytical approach is also given for routine design.