Wind load characteristics of a large-span steel structure factory building under downburst

The understanding and research on the wind field characteristics of downbursts and the wind loads on structures under their influence have emerged as pivotal research topics in wind engineering. This paper employs a simulator to generate downburst winds and investigates the wind load characteristics on the surface of a large-span steel structure factory building under such conditions. Initially, based on the theory of impinging jet, a downburst wind field is generated, revealing the spatial distribution patterns of wind speed, wind direction, and wind pressure. The validation of the simulated wind field is confirmed by comparing experimental results with measurements and theoretical models. Subsequently, the wind load characteristics of the factory building model are studied under the influence of downbursts by varying the radial distance of the downburst, wind direction angle and ground surface roughness. The results indicate that within the core region of the downburst, the model is primarily impacted by high pressure, resulting in relatively large positive surface wind pressures and forces. Conversely, in the horizontal diffusion area of the downburst, the model is predominantly influenced by horizontal wind speeds. Specifically, near the radial distance of the diameter of the simulator, the maximum negative pressure emerges at the leading edge of the roof's windward side, corresponding to the occurrence of the maximum lift force, lateral force, and overturning moment. In addition, higher roughness substantially elevates the wind pressure and wind force coefficients on the factory.