Downburst is the main source of extreme wind speed in non-typhoon areas, which has caused a large amount of transmission line damage all over the world. In order to reveal the wind-induced vibration response characteristics of a transmission tower-line system under downburst, the nonlinear dynamic analysis of a single tower and tower-line system is carried out, and the amplification effect of tower-line coupling and fluctuating wind on the dynamic response is studied. Then, the effects of three wind field parameters closely related to the average wind profile on the wind-induced response of the tower-line system are studied. The results show that under the action of the downburst, the tower-line coupling weakens the dynamic response to a certain extent, and the dynamic amplification factor of a single tower and tower-line system is 1.1 ~ 1.3; for the self-supporting tower, when the height of the peak wind speed is close to the height of tower, the responses of the structure are more unfavorable. When the vector superposition method is used, the storm moving speed (V_t) has little effect on the wind-induced response of the tower-line system. For large-span structures such as tower-line systems, to ensure the safety of the structural design, the value of the characteristic radius (R_c) should not be too small.

Downburst is a hazardous strong wind commonly encountered in thunderstorm weather. Influenced by ambient wind, the downdraft often accompanies horizontal movement while descending. Based on the impinging jet model, this study employs the large eddy simulation method to conduct computational fluid dynamics numerical simulations of stationary and moving downbursts. The evolution process, time-varying wind speed, and wind profile characteristics of the two types of wind fields are compared. This study also discusses the influence of η—which represents the ratio of the storm traveling speed (Vtr) to the jet velocity (Vjet)—on the wind field structure and verifies the applicability of the vector superposition principle in the simulation of the moving downburst. The results show the following: The wind speed and direction time histories obtained from the numerical simulation of moving downbursts have good consistency with the actual wind field records. The movement of the storm causes the near-surface wind field to lose its central symmetry, resulting in a bow-shaped distribution of extreme wind speeds at the storm's leading edge. As η increases, the non-central symmetry of the wind field becomes more pronounced, the maximum horizontal wind speed at the storm's leading edge gradually moves closer to the storm's center, peak wind speeds gradually increase, and the wind speed distribution at the storm's trailing edge shows the opposite trend. The vector superposition principle is not entirely applicable in the simplified analysis of moving downburst, causing significant errors when η is larger than 0.1.

Disaster investigation results have shown that most wind-induced damage to transmission towers is related to downbursts. To clarify the effects of downbursts’ parameters on transmission towers with different heights, studies were conducted on five transmission towers with different diameters under static and moving downburst wind conditions. As a comparison, the responses of the towers under normal wind conditions were studied. The results showed that the effect of downbursts on the response of the transmission tower increased with the distance between the downburst center and the tower (r) when r < 1.0 D_jet (D_jet is the jet diameter of downburst) and then decreased when r > 1.0 D_jet. The effects of jet diameter on the response of transmission towers with different tower heights were similar. As the jet diameter increased, the response of the tower continued growing until it reached a peak value and then steadily decreased soon thereafter. When the tower height was below 81.5 m, the wind load of the downburst on the transmission tower was significantly greater than that of the normal wind. As the tower height increased, the ratio of the transmission tower’s response under the two types of wind fields rapidly declined to about 0.91–1.01.

With the extensive construction of ultra-high voltage (UHV) transmission lines, the fatigue damage of steel tube members caused by vortex-induced vibration (VIV) in tubular towers has received growing attention. Although some progress has been made in the research of the VIV of steel tubes in uniform flow, there is still relatively scarce research on the VIV of steel tubes at various inflow conditions. In this paper, a series of wind tunnel tests are conducted to investigate the VIV of the steel tube subjected to uniform, turbulent, and oblique flows. Three turbulence intensities (I_u = 5.9%, 9.7%, and 12.6%), and four yaw angles (α = 10°, 20°, 30°, and 40°) are considered. The results show that the VIV response of the steel tube in the in-line (IL) direction is negligible compared to that in the cross-flow (CF) direction. The displacement amplitude gradually decreases as the turbulence intensity increases, accompanied by a more unstable response. For the inclined steel tube, the VIV maximum amplitude almost remains constant when α ≤ 20°, while it sharply decreased in the case of α = 30° and α = 40°. Furthermore, it was found that the so-called independent principle is applicable for α ≤ 10°.

The long-span Cross-Rope Suspended (CRS) system is composed of a transmission line (conductor), a long-span suspension cable, and an insulator. The previously introduced long-span CRS with a Tension Insulator (CRSTI) has shown applicability in mountainous areas. However, the tension insulator divided the suspension cable into several sections, which made the construction of a long-span CRS rather difficult. This paper introduces long-span CRS with a Suspension Insulator (CRSSI), in which the suspension cable was not disconnected, and the conductor was supported by a suspension insulator connected to the suspension cable. For the purposes of assessment, the initial shape of the suspension cable with concentrated loading from the self-gravity of the suspension insulator and the conductors was studied, and practical lengths in construction could be calculated exactly. Secondly, the structural performance of CRSSI, including its dynamic properties and the loading effect of wind, was discussed by means of numerical analysis. Vibration modes of the structure were obtained by FE analysis. Finally, structural deformation under static wind loading was studied. The result of the analysis showed that the stiffness of CRSSI was lower than CRSTI. The first frequency of CRSSI was 6% smaller than CRSTI. Regarding static wind loading, additional displacement of the insulator contributed to the maximum displacement of long-span CRSSI. Apparently, the displacement of the suspension insulator increased with wind speed. Moreover, the number of spans has an insignificant influence on tension force and deformation.

Downbursts are intense, short-duration wind events commonly associated with thunderstorms and are known to generate highly localized, near-ground wind loads that can significantly affect the structural safety of high-rise buildings. Despite their destructive potential, the aerodynamic effects of downbursts have not been fully incorporated into conventional design practices. This study investigates the surface pressure distribution and aerodynamic force characteristics of high-rise buildings subjected to steady-state downburst wind fields, with a specific focus on the influence of geometric parameters—namely, height-to-width (H/B) and depth-to-width (D/B) ratios. Experiments were conducted using an impinging jet wind tunnel system capable of reproducing localized, near-ground peak wind features typical of thunderstorm downbursts. Eight rigid building models with systematic variations in H/B and D/B were tested across multiple radial locations. Surface pressure data were used to compute both local and overall aerodynamic force coefficients. The results show that the peak horizontal wind speed occurs at a radial distance of r/Djet = 1.0. The turbulence intensity exhibits an inverse relationship with the mean wind speed and follows a vertical trend of first decreasing and then increasing with height. Increasing H/B significantly reduces mean and fluctuating drag forces and results in smoother lateral load distributions, while D/B modulates suction intensity on roof and rear façades. The findings enhance the understanding of shape-dependent aerodynamic behavior in downburst conditions and provide practical insights for wind-resistant design of high-rise buildings in thunderstorm-prone regions.