Recent research developments in the design of tubular structures

The statistical evaluation of material properties of cold-rolled tubes reveals that both the yield strength and yield ratio of these sections are expressed in functions of D/ t and are unusually high compared with those of hot-rolled steels. Based on statistical data for cold-rolled tubes, the local buckling and column buckling strengths and the rotation capacity of portals are evaluated and compared with existing test results. The statistical parameters of the resistance of tubular K-joints are shown. The resistance equation is applicable to K-joints in various materials and, further, can be used to develop other prediction equations for estimating the brace local buckling strength of K-joints and the ultimate capacity of multi-planar K-joints. In addition, results of a series of tests on complete tubular trusses are summarized, and the hysteretic behavior of trusses that sustain out-of-plane buckling of braces and chords is discussed. After buckling of the members, the joints are subjected to combined loads. The resistance and failure mode of the joints under cyclic loading are described.