Stability of Bridge Motion in Turbulent Winds

ABSTRACT Turbulence in wind velocity is shown to change the stability condition for the motion of suspension bridges. When the turbulence is convected at a high velocity, the time variation of the random excitation field becomes fast as viewed by the nonmoving structure. In this case the structural response can be approximated by components of a Markov vector process. Modeling the structure as a linear system and considering only the dominant torsional mode, the stability boundaries for the first and the second stochastic moments are obtained in terms of the mean wind velocity and the spectral level of the turbulence component.