Buckling behavior of a transversely stiffened aluminum beam flange

An offshore aluminum floor structure made from inverted T-shaped beams and a transversely stiffened deck was investigated experimentally and numerically. The deck assembly contained weld-connected extruded profiles with a closed trapezoidal stiffener and flat plating, which constituted the beams' top flange. A bending test was designed to produce a state of pure axial compression perpendicular to the stiffeners in the deck without the influence of transverse loading on the deck. The compressed floor deck developed buckling deformations where the deck profiles/stiffeners deflected elastically with alternating upward/downward buckling bows between the floor beams, occurring at an average membrane compression stress of 30 N/mm2 in the deck plate. Ultimately, the average membrane stress was 54 N/mm2, and the deck stiffener deflections were >10 mm. The compressive deck plate stresses gradually redistributed to the regions near the webs of the floor beams, where failure occurred by inelastic buckling of the deck plate. FE simulations accurately reproduced the bending resistance of the floor structure, the observed buckling forms and displacements in the deck, and the strain and stress distributions in the deck plate. The existing design provisions for compressed transversely stiffened plates are insufficient and provide capacities less than half of that from the experiment.