Strength of Square Steel Panels

New design formulas are derived for the large-deflection strength of square steel panels subjected to simultaneous lateral pressure and inplane thrust. Using a rigid-plastic planar-segment idealization the influence on strength of inplane edge conditions that are: (1)Fully restrained; (2)free to pull in but constrained to be straight; and (3)completely unrestrained; all three conditions with and without flexural clamping, is examined. It is shown that strength under both types of loading at high deformations is largely dependent on inplane conditions for which asymptotic strengths are given. By relating the lateral deflection parameter of the planar-segment idealization to the edge-slope as well as the central deflection of actual panels, predicted strengths bound published test data.