Design of Frames by Relaxation of Yield-Hinges

A method is herein developed for determining the loading condition that causes the collapse of a rigid frame structure. It is shown that the location of the “yield-hinges,” when the structure is on the verge of collapse, is independent of the stiffness of the individual members. The method consists of (1) the arbitrary distribution of moment to the joints of the structure, and (2) the adjustment of this distribution by the trial-and-error method, until the highest ratio of actual moment to limit moment—at any point in the structure—reaches a minimum. The locations of the yield-hinges are the points at which these minima occur.