Plastic response of laterally restrained adhesive-bonded compound steel beams

Compound beams are generally formed by welding or bolting steel elements to the flanges of an I-section or universal beam. A compound beam is used where the depth is limited and the universal beam is not strong enough to resist the bending stresses. Steel plates or other steel elements are welded or bolted on both flanges of the I-section to enhance its capacity. The purpose of this study is to determine the suitability of using an adhesive as an alternative to bolting or welding in fabricating compound beams. Unlike welding and bolting, adhesive bonding eliminates stress concentration and residual stresses, however, adequate bonding techniques are required if this method is to be applied more widely. Two series of compound cross-sections of four specimens each were fabricated and tested in flexure under a two-point loading, and the results compared to the theoretical plastic capacity of the compound section. Of the eight specimens tested, six failed by flexural yielding, proving that adhesives can serve as a suitable alternative to bolting and welding in the manufacturing of compound beams.