Wind tunnel tests and numerical simulations for snow load design of saddle-shaped roofs

Integrating wind tunnel tests and numerical simulations, this study systematically investigates snow load distribution on saddle-shaped roofs. Scaled model tests under varying wind directions (0°, 45°, 90°) and supplementary simulations (22.5°, 67.5°) identified the 0° direction as the most unfavorable case. A validated numerical model (normalized RMSE = 8.87%) was then employed for parametric analyses of inflow wind velocity, roof span, and rise-span ratio. Key findings reveal that wind velocity governs the erosion-transport-deposition process, with higher velocities exacerbating load non-uniformity. Roof span determines snow coverage extent: smaller spans exhibit a typical half-span distribution, whereas larger spans result in wider coverage and more uniform patterns. The rise-span ratio exhibits a synergistic amplification effect with wind velocity: a larger ratio leads to more pronounced flow acceleration, which enhances windward erosion and exacerbates leeward accumulation. Based on these findings, three representative snow load distribution patterns (uniform-expanded distribution pattern; half-span distribution pattern; and windward-erosion and leeward-deposition pattern) and their corresponding snow load coefficients are proposed, offering theoretical insights and practical references for engineering design of saddle-shaped roofs.