The Excel sheet estimates the variation of wind loads with building height. It calculates the wind pressure intensity at various levels based on standard wind pressure formulae, allowing engineers to understand how wind pressure increases with elevation. This is particularly important when designing tall buildings, towers, and cladding systems.
Why Wind Load Varies with Height
Wind speed is not uniform over the height of a building. Near the ground, surface roughness — from terrain features, vegetation, and adjacent structures — slows the wind significantly. As height increases, the wind is less obstructed and speeds increase, resulting in higher dynamic pressures on the structure.
This phenomenon is captured in wind codes through the velocity pressure exposure coefficient (Kz), which increases with height and depends on the surrounding terrain (exposure category).
The Variation Profile by Exposure Category
Different terrain types produce different height-velocity profiles:
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