Parametric Study on the Nonlinear Dynamics of a Three-Stay Cable Network under Stochastic Free Vibration

Crossties and cable networks are used on cable-stayed bridges to mitigate wind-induced stay vibration. A nonlinear free-vibration analysis of a cable network with random oscillation amplitudes is presented in this study. Specifically, a nonlinear restoring-force spring model is introduced at the crosstie to simulate in-plane network free vibration at large amplitudes. The current constitutive model of the crosstie is also combinedwith taut-cable theory to simulate the dynamics in the stays and is solved by the equivalent linearizationmethod. Stochastic functions are introduced in the model because the measure of the amplitudes produced by windand rain-wind–induced vibrations in the network can be affected by various uncertainties. The stochastic approximation (SA) algorithm is applied to find the roots of the characteristic polynomials associated with a stochastic vibration amplitude parameter. Brute force Monte Carlo methods are also used to analyze the SA convergence properties. DOI: 10.1061/(ASCE)EM.1943-7889.0000887. © 2014 American Society of Civil Engineers.