Corrugated plate having variable material thickness and method for making same

A method for producing relatively lightweight, high strength corrugated metal plate by cold rolling it from flat metal plate, the corrugated plate having a generally trapezoidal cross section defined by parallel, longitudinally extending, alternating corrugation peaks and corrugation troughs interconnected by inclined corrugation sides, the method comprising the steps of forming a substantially flat plate having longitudinally extending, alternating relatively thin and relatively thick plate sections;

• corrugating the substantially flat plate by deforming the plate so that the relatively thick sections define at least portions of the corrugation peaks and corrugation troughs and the relatively thin sections define interconnecting corrugation sides;
• and forming longitudinally extending, curved corrugation segments in the relatively thin plate sections between lateral edge portions of the corrugation peaks and corrugation troughs and corrugation sides adjoining such edge portions.