Quasi-secant behaviour of elastic cables for cable-stayed structures

In order to overcome the drawbacks of the Dischinger's theory when it is employed for modelling cable-stayed structures, a "quasi-secant" approach for the analysis of elastic stays is proposed. Starting from the secant approach, an explicit constitutive relationship for the cable is deduced, giving a second order approximation both with respect to the stress variation and the apparent chord-strain one. Furthermore, the cable-structure interaction is modelled through a second order displacement approach, able to take into account the finite variation of the cable's chord direction induced by the deformation of the stay-supported structure. In this way a closed-form formulation is obtained which, unlike classical secant model, does not need iterative procedures. Several test-cases and benchmarks are developed on different stay configurations, in order to show the effectiveness and the accuracy of the proposed model.