DYNAMIC ANALYSIS OF A GUYED MAST WITH UNCERTAINTIES ON THE STIFFNESS AND THE NOMINAL WIND VELOCITY

JORGE BALLABEN; MARTA B. ROSALES; RUBENS SAMPAIO

Buenos Aires

Congreso; PANACM 2015-1st Pan-American Congress on Computational Mechanics and XI Argentine Congress on Computational Mechanics; 2015

AMCA, AMMNI,ABMEC, ACMENICA,USACM,SCMC,SVMNI

Nowadays the use of guyed structures as support for telecommunication antennas (radio, TV, internet, cell signals) is a practice widely adopted. Nevertheless, detailed studies of the dynamic response of the structural system under natural actions, as wind or earthquake are not frequent, despite the potential of adverse impact, particularly in the quality of the transmission. In this work, the dynamic response of a guyed mast is analyzed under wind load action. The simplified structural model consists of a beam-column model accounting for the second order effect due to axial loads and one guy. The guy is represented by an extensible cable governed by nonlinear equations. The wind load is calculated from the wind velocity field. The resulting governing system is discretized using finite elements and a reduced order model is afterwards developed using vibration modes as a basis. The tower stiffness can vary due the reinforcement of the structure. Since it is not easy to foresee their behavior, an uncertainty quantification study appears necessary. Because the nonlinear structures show special sensitivity to dynamic loads, the nominal value of wind velocity (used to construct the wind loads) is also considered as a stochastic parameter. Then, Monte Carlo simulations are performed. The probability distribution functions (PDF) of the results are observed accounting for each parameter separately. Afterwards, both parameters are considered stochastic by means of a joint distribution. Both parameters show very different types of influence on the statistics of the response.