Comparative investigation of force coefficients for complex open frames

l Open framed buildings are a feature of mining and mineral processing facilities. While often unclad, they can vary significantly in the density of structural elements and equipment within, creating wind flow blockages that strongly influence wind loads. Estimating these loads presents challenges for structural engineers in developing a conservative yet practical wind force-resisting system. A limited number of publications provide guidance, generally based on low-blockage lattice structures, and their application to higher-blockage frames may not be appropriate. A review of the historical basis of several guidelines highlights the need for further work examining higher blockages. To address this, a conceptual model of flow through an idealized open framed building was developed as the basis for reviewing published guidance. This was undertaken using calculations from Australian Standard AS/NZS 1170.2 "Structural design actions, Part 2: Wind actions," ASCE "Wind Loads for Petrochemical and Other Industrial Facilities," and CFD simulations, with results compared across the three methods. While the study cannot fully determine applicability, it shows that predicted force coefficient trends from AS/NZS 1170.2 and CFD are generally aligned, whereas ASCE predictions are consistently higher.