Minimum Weight Plastic Design of Continuous Frames

A method by which typical frames may be designed for minimum weight to resist ultimate loads on a collapse basis is presented. Simple plastic theory is assumed to apply, although the procedure is such that members subject to axial loads are included. There is no attempt to define an optimum design, except in the sense of minimum weight. Factors such as fabrication costs and deflection limitations have been subordinated to the requirements of minimum weight, although it is realized that minimum weight is not always the most important factor. The proposed method is unique, in that it is a procedure leading directly to the correct minimum weight design without recourse to trial mechanisms, load interaction curves, or design charts that characterize existing procedures.