PLASTIC-COLLAPSE ANALYSIS OF TORSION

This paper is concerned with the plastic-collapse analysis of structur al steel I-section members subject to torsion. It proposes and exempli fies a method of plastic-collapse analysis that is much simpler than e lastic analysis. The load factor at plastic collapse is obtained from the sum of the independent load factors for uniform-torsion plastic co llapse and warping-torsion plastic collapse. This plastic-analysis met hod allows a method of plastic design to be used for torsion that is m uch simpler and more economical than first yield design. The use of pl astic analysis and design will facilitate the design of steel torsion members and lead to more economical structures.