Vindlast

Vindlast is a term used in civil and structural engineering to denote the wind load acting on a structure. It encompasses the external forces produced by wind on building surfaces and components, including horizontal pressures on façades, vertical uplift on roofs, and torsional or dynamic effects on irregular shapes. The term originates from Danish and Norwegian where vind means wind and last means load; it is widely used in Northern European practice, and the concept is covered by international design standards such as Eurocode 1.

Wind load is determined by several factors: the external wind speed at height, the exposure category of the site, terrain roughness, and topography, as well as the geometry and orientation of the structure. In simplified form, dynamic pressure q = 0.5 rho V^2 is used, where rho is air density and V is wind speed. The surface pressure p on a given element is p = Cp * q, with Cp a pressure coefficient that depends on the surface orientation and shape. For dynamic effects and gusts, a gust factor or dynamic amplification is applied, and the load is obtained by multiplying p by the affected area.

In design practice, vindlast is incorporated into codes and specifications to ensure structural safety and serviceability. National and regional standards, alongside Eurocode 1, provide procedures for determining wind loads under different exposure categories and for various structural forms. Related topics include wind engineering, wind tunnel testing, and load combinations in structural design.