Lateral Stability of Beam and Deck Structure

The theoretical equations describing lateral buckling of deep beams attached to a nailed wood deck were verified by experiment. Because the effects of beam depth and span length on lateral stability are well known, the experiments were designed to study the influence of deck stiffness on stability of a beam-deck structure. A pair of deep beams, with attached deck, was loaded with end moments to produce pure bending in vertical planes parallel to the longitudinal axis of the beams. The critical bending moment at which lateral buckling of the beam-deck structure occurred was observed for several decks having different shear stiffnesses. Observed critical bending moments were within 7% of those predicted by theory. It was found that critical bending moments twice those for unsupported beams could be obtained with a deck of moderate shear stiffness fastened to the compression side of the beams.