Contemporary tall buildings constructed with high-strength and light-weight materials become relatively flexible and lightly damped, and the fluctuating wind forces acting on the buildings may cause excessive vibrations, especially at the vicinity of vortex lock-in wind speed, where the natural frequency of the buildings is synchronized with the vortex shedding frequency. Given that tall buildings tend to be designed with unconventional shape involving innovative structural systems and complex geometry, the correlations among three force components may accentuate building motions significantly. In this study, the coupling characteristics between the alongwind and crosswind vibrations of tall buildings with symmetric shape and distinct natural frequencies in two directions are investigated through a serious of aeroelastic model tests. The response standard deviations and power spectral densities are calculated, respectively, based on the displacement data measured at multiple levels of wind speed and structural damping ratio. Then the coupled response is extracted from the alongwind response in frequency domain through Fourier transform and inverse Fourier transform, and the standard deviations of the coupled response are calculated based on time history analysis, which are compared with that of the crosswind response to investigate the relationship between the alongwind and crosswind motions. Moreover, the amplitude ratio, phase difference, and coherence of the response components are also calculated for further discussing the coupling effects and examining the coupled vibration characteristics.

At the vicinity of vortex lock-in wind speed, the nonlinear aerodynamic damping effect of super-tall buildings is significant, which can greatly promote the surge of vortex-induced vibration in the crosswind direction, where the crosswind response characterized by harmonic amplitude shows narrow-band hardening non-Gaussian characteristic with the kurtosis well below 3, and the corresponding probability distribution of amplitude process distinctly differs from that of typical random buffeting response. Although the moment-based Hermite translation model has been widely used for estimating the extreme value distribution of non-Gaussian process, it fails to represent the probability distribution of hardening non-Gaussian amplitude process, notably for the response with a kurtosis close to 1.5. In this study, a new translation model based on orthogonal expansion of random processes is developed for obtaining the non-Gaussian amplitude process from an underlying Gaussian amplitude process, and the probability density function of the non-Gaussian amplitude process is derived by mapping the cumulative distribution function. The coefficients of translation model are determined by minimizing the errors between the estimated probability density functions and target values through nonlinear optimization, and the closed-form semi-empirical formulations, which connect the model coefficients with response kurtosis, are also proposed using least-square curve fitting. Moreover, the effectiveness and monotonicity of the proposed translation model are examined. This model can be readily incorporated into the extreme value analysis of crosswind response and facilitate the evaluation of wind-induced fatigue of super-tall buildings.

This study investigates the wind-resistant configuration of a seven-row single-span double-layer cable-supported photovoltaic (PV) array through conducting systematic analysis of the interference effect. Wind tunnel pressure measurement tests were conducted on a rigid model to obtain the wind force coefficients and torque coefficients under different wind directions. The time histories of wind pressure obtained from the tests were imported into a finite element (FE) model to calculate the vertical displacement and torsional angle responses. The wind-induced responses of different configurations with varying quantities and arrangements of longitudinal connections and wind-resistant cables were analyzed. The results indicate that in the case of head-on wind, wind force is the most unfavorable, and the correlation between wind force and torque is relatively low. In the case of oblique incoming flow, torque is the most adverse, and the correlation between wind force and torque increases. Directions of vertical displacement are opposite in windward and leeward wind scenarios, but directions of torsion angle remain consistent. Overall, the wind-induced responses at mid-span are greater than those at the edge, and the first-row response is more significant than that of the subsequent rows. The wind-induced vibration under windward flow conditions is more adverse when compared to that under leeward flow conditions. However, the downstream adverse interference effect caused by leeward incoming flow is more prominent. Based on the comprehensive analysis of wind loads and wind-induced responses, the whole structure is divided into three zones, namely, wind-induced response control zone, local wind pressure control zone, and wind effect transition zone. A wind-resistant configuration with longitudinal connection arrangements considering both safety and economic benefits is proposed, which provides a reference for the wind-resistant design of similar structures.