The aim of the present study is to empirically derive a simple and reasonably accurate expression for predicting the ultimate strength of longitudinally stiffened panels under uniaxial compression for use in the context of parametric structural reliability studies of ship hull girder global behavior. Existing test data on the ultimate compressive strength for stiffened panels were used as the starting point for the formulation. A study of the collected data indicated that the data needed supplementation in order for the derived formula to be applicable to a desired wide range of panel dimensions. Hence a series of 12 longitudinally stiffened plates having three different plate slenderness values were in the present study tested up to the collapse state under uniaxial compression. On the basis of the previously collected and newly developed test data, an useful empirical expression for predicting the ultimate compressive strength of stiffened panels, expressed in terms of the plate slenderness ratio and the column (stiffener) slenderness ratio, was derived. The formula implicitly includes the influence of initial imperfections at a moderately large level. All test data (previous and new) are documented.
Stiffened steel panels are the basic strength members in ship and offshore structures. Due to their simplicity in fabrication and excellent strength to weight ratio, stiffened steel panels are also widely used in land based structures such as box and plate girder bridges. During the 1970s, the unfortunate occurrence of a few failures in such bridge structures stimulated extensive theoretical and experimental research work on failure of stiffened panels. In ship design, the hull girder strength of ships is often governed by the collapse behavior of deck or bottom panels (Caldwell 1965, Pail (et al. 1996).
