Chengtao Zhang’s research while affiliated with Chongqing University of Science and Technology and other places

The nonlinear effects exhibited by structures under the action of wind loads have gradually stepped into the vision of wind-resistant researchers. By summarizing the prominent wind-induced nonlinear problems of four types of wind-sensitive structures, namely tall buildings, high-rise structures, flexible bridges, and transmission lines, the occurrence mechanism of their nonlinear effects is revealed, providing cutting-edge research progress in theoretical studies, experimental methods and vibration control. Aerodynamic admittance provides insights into the aerodynamic nonlinearity (AN) between the wind pressure spectrum and wind speed spectrum of tall building surfaces. The equivalent nonlinear equation method is used to solve nonlinear vibration equations with generalized van-der-Pol-type aerodynamic damping terms. The elastic–plastic finite element method and multiscale modeling method are widely employed to analyze the effects of geometric nonlinearity (GN) and material nonlinearity (MN) at local nodes on the wind-induced response of latticed tall structures. The AN in blunt sections of bridges arises from the amplitude dependence of the aerodynamic derivative and the higher-order term of the self-excited force. Volterra series aerodynamic models are more suitable for the nonlinear aerodynamic modeling of bridges than the polynomial models studied more in the past. The improved Lindstedt–Poincare perturbation method, which considers the strong GN in the response of ice-covered transmission lines, offers high accuracy. The complex numerical calculations and nonlinear analyses involved in wind-induced nonlinear effects continue to consume significant computational resources and time, especially for complex wind field conditions and flexible and variable structural forms. It is necessary to further develop analytical, modeling and identification tools to facilitate the modeling of nonlinear features in the future.

Wind-induced vibration coefficient β is an essential parameter for the structural wind-resistant design. In order to provide accurate design wind loads, β of a landscape tower with curved and twisted columns and spiral beams (short for LT) is studied by wind tunnel test and numerical simulation. The results show that the displacement wind-induced vibration coefficient is greatly affected by wind yaw angle. Moreover, the inertial load wind-induced vibration coefficients increase along the height and increase sharply at the platform position. Due to the influence of nonuniform shape and mass distribution and wind yaw angle, β calculated by the Chinese and American load code does not apply to LT structures. In addition, this article puts forward some suggestions for the shortcoming in the use of code to calculate β of LTs and made some prospects for future research on wind-resistant design of LTs, hoping to provide theoretical guidance and thinking inspiration for future research.

The complex aerodynamic shape and structural form affect the wind-induced vibration coefficient β of landscape towers with a twisted column and spiral beam (short for LTs). To clarify the β distribution characteristics, evaluate the applicability of existing load codes, and provide accurate design wind loads, wind tunnel tests and numerical simulations were carried out on a LT. The LT’s aerodynamic coefficients and wind-induced responses were measured using rigid sectional and aeroelastic models. Furthermore, the displacement wind-induced vibration coefficient βd and inertial load wind-induced vibration coefficient βi(z) of the LT were calculated from these measured data. Combined with test data and a finite element model, the impacts of the wind speed spectrum type, the structural damping ratio ξ, and the peak factor g on β of the LT are analyzed. The accuracy of β of the LT calculated by Chinese and American load codes was examined and given the correction method. The results showed that the wind yaw angle had a significant impact on βd of the LT, which cannot be neglected in current load codes. The abrupt mass increase at the platform location makes the distribution characteristics of βi(z) of the LT different from conventional high-rise structures. The values of ξ and g have a significant impact on the calculation results of β, which are the key to the accurate design wind loads of LTs. The existing load codes are not suitable for LTs, and the correction method proposed in this paper can be used to improve them.