Assessment of the Elastoplastic Nonlinear Static and Dynamic Behavior of Guyed Antenna Towers Subjected to Cable Rupture

Cable-stayed antenna towers are slender structures composed of a central mast and several cable levels and exhibit a highly non-linear behavior under static and dynamic loads, due to the mast-cable interaction and the tower height. Many accidents reported in literature are due to cable rupture. Thus, the aim of the present work is to study the effect of cables rupture and plasticity on the load capacity, stability and nonlinear oscillations of a cable stayed tower considering the influence of both geometric and material nonlinearity. For this, finite element models of cable-stayed towers with two levels of pre-tensioned cables are developed, considering both fan and parallel cable distributions. Initially, the linear behavior of the structure is evaluated through the natural frequencies and critical loads. Next, the non-linear equilibrium paths of each model are obtained, applying the concept of modal imperfection. Finally, forced free and damped vibration analyses are performed. For this, time responses, phase plane projections, Fourier transforms and spectrographs are used. The results confirm and quantify the strong influence of the loss of one or more cables on the response of the guyed tower. © 2022 Ernst & Sohn GmbH.