An approximate procedure for determining the elastic critical or buckling loads of plates, subjected to combinations of in-plane loading, is described. The analysis is sufficiently economical in computer requirements to permit parametric studies and has been used to obtain interaction formulas for different combinations of loading. A general description of the method is followed by its application to the evaluation of the critical loads of simply supported rectangular plates subjected to in-plane patch, shear and bending stresses, and combinations of such stresses, which occur in the web panels of fabricated plate girders carrying significant wheel loads

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