Stability of steel struts with externally anchored prestressed cables

Externally anchored prestressed cables can be employed to enhance the stability of steel truss compression elements significantly. To demonstrate this concept, a system comprising a tubular strut subjected to an external compressive load and a prestressed cable anchored independently of the strut is studied. Energy methods are utilized to define the elastic stability of the perfect and imperfect systems, after which the first yield and rigid–plastic responses are explored. The influence of the key controlling parameters, including the length of the strut, the axial stiffness of the cable and the initial prestressing force, on the elastic stability, the inelastic response and the ultimate strength of the system is demonstrated using analytical and finite element (FE) models. To illustrate the application of the studied structural concept, FE modelling is employed to simulate the structural response of a prestressed hangar roof truss. A nearly two-fold enhancement in the load-carrying capacity of the truss structure is shown to be achieved owing to the addition of the prestressed cable. •Analytical modelling of steel struts with externally anchored prestressed cables.•Post-buckling stability dependent on ratio of cable axial stiffness to strut bending stiffness.•Failure evaluated from Perry-Robertson type approach and a rigid-plastic analysis.•Ultimate strength predictions verified through FE modelling of a prestressed truss.•Two-fold enhancement in capacity demonstrated compared to system without cables.