Comparison of international wind loading codes with a proposed Computational Fluid Dynamics framework considering the slenderness of buildings

This study compares the latest editions of five international wind loading codes -namely, the American code (ASCE 7-22), the Japanese code (AIJ-2019), the Australian/New Zealand code (AS/NZS 1170.2:2021), the European code (EN 1991-1-4:2018), and the Canadian code (NBCC 2020)- against a proposed Computational Fluid Dynamics (CFD) framework. The comparison is based on 12 isolated square buildings situated in open terrain, with height-to-plan-dimension ratios (H/B) ranging from 1 to 12. The objective is to classify each code according to the H/B ratio, identify its strengths and limitations, and highlight the scenarios where wind tunnel testing becomes essential. The influence of building natural frequency is also examined. Numerical results reveal that, for along-wind loads, ASCE 7-22 aligns well with CFD predictions for H/B ≤ 6, when the directionality factor is not considered. AIJ 2019 and NBCC 2020 show good agreement for H/B ≤ 8, AS/NZS 1170.2:2021 for H/B ≤ 5, and EN 1991-1-4:2018 for H/B ≥ 6. For across-wind base moments, AS/NZS 1170.2:2021 matches the CFD results well at H/B ratios of 3 and 4. In terms of acceleration, EN 1991-1-4:2018 provides the best match for along-wind acceleration, while NBCC 2020 performs best for cross-wind acceleration. Furthermore, the findings confirm the necessity of employing wind tunnel testing or a CFD-based approach when the building exceeds an H/B ratio of 4, as across-wind effects become dominant beyond this threshold. • Using the Computational Fluid Dynamics (CFD) method, this study conducted 96 simulations. • CFD analysis results have been compared against 5 international wind loading standards and wind tunnel data. • This study concludes by classifying each wind code based on the building height-to-plan dimension ratio (H/B). • The influence of varying building frequencies was investigated for each wind standard. • This study identifies a threshold H/B ratio beyond which a wind tunnel test is necessary.