Rational design analysis of stub columns fabricated using very high strength circular steel tubes

The mechanics of the compressional behaviour of stub columns fabricated from Grade 350 steel plates welded to very high strength (VHS) circular tubes are investigated in this paper. In the investigations comparisons of experimental load-axial shortening curves are made with the results of a postulated design analysis set up to examine the complete load-shortening behaviour of such members. Ramberg-Osgood type stress-strain equations are set up for the plate and tube materials. A procedure is described to evaluate the loads in individual plate and tube elements as the axial shortening is increased until the 0.2% proof strain for the VHS tube material is attained. Upon reaching this strain it is assumed that failure ensues as the result of a simple plastic mechanism occurring in the tubes. Comparisons of the load-axial shortening curves given by this analysis and experimental results indicate good agreement.