Uncertainty in dynamic properties of flexible buildings to wind load

Setting appropriate values of the modal parameters of tall buildings under wind actions is a challenge. Despite both frequency and damping ratio are affected by uncertainty, the latter is recognized to be the main source of randomness in the assessment of the building response. Different analytical formulations have been proposed through the years, relating the damping ratio to the amplitude of oscillation, to the building height, and to frequency. However, these appear to disagree with each other, leading to ifferent estimates of damping. The main aim of the paper is the assessment of stochastic models for the dynamic properties of flexible buildings. To achieve it, available online frequency and damping databases are used. First, the accuracy of some available analytical models is assessed. Then, the datasets are analysed, and probabilistic models are proposed describing the uncertainty in frequency and damping ratio.