Wind Load Characteristics of Large-Span Shell-Shaped Roof with Decorative Spiral Strips

In order to understand the effect of decorative structure on the wind load characteristics of a large-span shell-shaped roof, the wind pressure distribution characteristics of a high-speed railway station roof with a decorative spiral strip on a certain surface were studied. First, a numerical wind tunnel model for a long-span shell-shaped roof with decorative strips on its surface was established, and the wind pressure distribution on this roof was simulated on the basis of the Reynolds time-averaged RNG k-ε turbulence model. The reliability and applicability of the numerical model were then verified through comparative analysis against wind tunnel test results. Meanwhile, a numerical wind tunnel model for the same roof without decorative strips was also built, and numerical simulations were carried out. By comparing the numerical results of roofs with and without surface decorative strips, the wind field variation characteristics of the long-span shell-shaped roof with decorative spiral strips were analyzed from the aspects of wind-load lift coefficient, wind-load local shape coefficient, and regional velocity vector distribution. Results show that the relative error of the shape coefficient between the numerical simulation and the wind tunnel test was within ± 25%. The deviation rate of the wind-load lift coefficient was between −7.1% and 6.1%. Compared with the simulation result of the roof without surface decoration strip, the wind-load lift coefficient of the roof with surfacedecoration strip was smaller, and the maximum deviation rate could reach 22.4%, which means that the setting of the decorative strip is beneficial for reducing the wind-resistance of the large-span shell-shaped roof. It was also found that the setting of decorative strips would reduce the local wind pressure in most areas of the roof by 0%–50%. However, it also increased the wind pressure in individual regions on the roof by 2–5 times, which should be paid more attention to in the design of local accessory components on the roof. Besides, there is some narrow pipe effect between the decorative strips, and the blocking effect of the decorative strips on airflow leads to the generation of apparent vortices between the strips, making the wind pressure at the strips higher. Furthermore, as the wind flows around the building, the roof with decorative strips on the surface will produce a larger range of trailing vortices on the leeward side than the roof without decorative strips.