Composite columns made of standard cold-formed steel channels and plywood

Twenty-nine column specimens fabricated from 18-gauge cold-formed steel lipped channel sections and plywood were tested to failure under concentric axial compressive loading. The specimens in total consisted of twenty composite columns of cold-formed steel and plywood, six cold-formed steel only columns, and three plywood only columns. The composite columns of cold-formed steel and wood included four different configurations, the cold-formed steel only columns consisted of two different configurations, and plywood only columns consisted of one configuration. Structural connection between cold-formed steel sections and plywood components was achieved by using self-drilling screws and epoxy adhesive.;This research was developed to experimentally evaluate the ultimate strength and buckling behaviour of composite columns with emphasis on the effect of plywood strips and epoxy adhesive. Strips were connected to the flanges of the cold-formed steel sections using epoxy adhesive in addition to self-drilling screws. Except for the singly symmetric cold-formed steel only and plywood only columns, all columns experienced interaction of local and flexural buckling. The singly symmetric cold-formed steel only columns underwent a combination of local and torsional-flexural buckling. The plywood only columns failed by pure flexural buckling. It was found that the plywood components and epoxy adhesive had positive influence on the overall strength and buckling behaviour of the composite columns.;Recommended standard design load values determined in accordance with CSA S136-01 for cold-formed steel structural members and CSA O86-01 for wood structural members were found to be conservative as compared to ultimate capacities obtained for specimens from experimental testing.