Studies On Stability Behavior And Design Method Of Shuttle-Shaped Axially Loaded Column

The shuttle-shaped axially loaded column, as a new type of structural member,has extensive application perspective in large-span spatial steel structures for itsspecial and beautiful appearance. The aim of this dissertation is to explore its rationaldesign method by studying its local and overall buckling, as well as ultimateload-carrying capacity, so as to promote its application in structural engineering.Firstly, the local and overall buckling behaviors of two kinds of fabricatedshuttle-shaped axially loaded columns, with circular hollow section and rectangularhollow section are studied respectively. The fabricated shuttle-shaped column can besimulated as a prismatic column by employing the effective inertial moment andeffective length where the fabricated shuttle-shaped column has the same overallbuckling load as the equivalent prismatic column. Thus the design procedure ofshuttle-shaped column is simplified by introducing effective slenderness ratio.Secondly, the shear stiffness formula of prismatic latticed columns withlongitudinal and diaphragm steel pipes are derived. With those, elastic critical loadand ultimate load-carrying capacity of prismatic latticed pipe columns can becalculated conveniently.Moreover, the shuttle-shaped latticed columns with two or three longitudinalpipe components are investigated by employing ANSYS, taking into account of bothmaterial and geometric nonlinearity. It is found that because of non-uniform shearstiffness and flexural stiffness along the axial of column, there exist two kinds ofbuckling modes, namely, symmetrical flexural mode and anti-symmetrical shearmode. Based on the elastic critical load, the design method for shuttle-shaped latticedcolumn is proposed and is verified by nonlinear FE numerical results.Lastly, according to the investigation for elastic buckling mode ofmulti-component shuttle-shaped latticed column, it is concluded that the ideal ratio oflength to mid-section radius, namely 13~15 is recommended. It is verified that thedesign method using effective slenderness ratio and column curve is available formulti-component shuttle-shaped latticed column.