Second‐Order Elastic‐Plastic Analysis of Multistory Building Frames by Marching Technique

Abstract

In two previous papers, second‐order elastic analysis of multistory building frames by marching technique [1] and elastic‐plastic analysis of rectangular frames [2] have been dealt with. The algorithms described in those two papers are now combined into an efficient computer program for conducting the elastic‐plastic analysis of multistory building frames by marching technique. With this program, the response of a multistory building frame, subjected to uniform loads on the beams and lateral loads at the floor levels, may be traced from the service load condition to proportionate overloads until collapse through sequence of formation of plastic hinges. Because & am spans are not divided into elements in the analysis, plastic hinges are assumed to remain at the same locations once they are installed on them. Consequently, moments in beams may later exceed slightly the plastic moment capacity. It is believed that the algorithm is useful to form a basis for further investigations, such as considerations for more than the two essential second‐order effects, or for effects of semirigid beam‐to‐column connections and of axial force on the plastic moment capacity.