Preliminary studies of steel-plywood composite structures

The paper describes a preliminary study into the design and behaviour of steel plywood composite beams. These beams comprise a web using conventional readily available plywood with flanges made from cold-formed steel sections. The most highly stressed parts are the steel flanges and the plywood webs, typically 10-12 mm thick provide shear resistance and are not susceptible to web buckling or crippling. The flanges are attached to the webs using self-tapping screws. The paper describes the manufacture and assembly of steel-plywood beams and presents the results of a series of structural loading tests on the beams. The variables considered in the tests are: the thickness and geometry of the flange, the spacing of fasteners, the thickness of plywood and the use of orientated strand board. The results show that steel-plywood beams are an easily assembled alternative to other lightweight fabricated joist systems for the medium span range 5-12 metres.