When air warms up, the air pressure changes. Wind is generated by the difference in air pressure between different air masses of warm and cold air. Air particles from a high-pressure area flow into a low-pressure area until the difference in air pressure equalises again. The greater the pressure difference between the air masses, the faster the wind speed. A storm will form when a high-pressure area meets a low-pressure area.
Wind speed is measured in metres per second, kilometres per hour or nautical miles per hour. It depends not only on air density, temperature and solar radiation, but also on the topography, i.e. the surface composition and height structures of the terrain. Wind strength is not an exact or objective scale. The Beaufort scale for determining wind strength, named after Sir Francis Beaufort, is based on its observable effects: from calm weather (wind force 0), when smoke rises straight up, to the most severe destruction wreaked by nature, a hurricane (wind force 12).
Wind loads are one of the climatic variables that can affect a building. Like other impacts, they must be taken into account in the construction planning and statics calculations. When wind flows onto a structure, positive pressure is created on the surface facing the wind, and negative pressure (suction) is created on the opposite side. At the same time, turbulence is created at the corners of the building due to the so-called ‘wind tunnel effect’, which leads to higher wind suction. A particularly good example of this can be observed on motorways when driving past a lorry. The tarpaulin on the sides of the cargo just behind the driver's cab can sometimes be seen lifting outwards. This difference in the relative motion of air and object is an example of the wind tunnel effect. The velocity pressure in kN/m² is determined from the wind speed in m/s.
The force with which wind acts on a building varies depending on its location. Areas with similar conditions are grouped into wind load zones in DIN EN 1991-1-4. This European-wide standard (also called Eurocode) regulates how the effects of wind loads on a building are to be determined. The shape of the building, roof pitch and building height as well as many other factors are also taken into account in order to determine the wind load to be used in the structural calculations.
A lightweight building’s load-bearing capacity depends on its static system, construction and the strength of its aluminium profiles. Herchenbach’s modular system offers four different profile thicknesses. In principle, the wider and higher the building and the higher the snow or wind zone, the stronger the profiles used must be. Different profile thicknesses are used in the various wind zones depending on the building’s height, width and length. A freely selectable truss spacing of 4 or 5 m configures the safest and most cost-effective construction for the respective wind zone. Approved structural analyses are already available for more than 500 building geometries in the Herchenbach modular system, eliminating the need for expensive individual structural analyses. Lightweight buildings from Herchenbach can be erected in different wind zones and are as safe as buildings made of steel, concrete or masonry.
What effects does the wind load have on a lightweight building?
Lightweight buildings are exposed to various impacts. In addition to constant loads such as the building’s dead load, there are variable loads such as wind load or snow load. The velocity pressure acting on the building depends on the wind speed or wind zone, the terrain and the building height. The shape of the roof also plays a role. To ensure that the building construction is safe and load-bearing, the individual components must be perfectly calibrated and expertly assembled. As the forces acting on the lightweight building can be optimally distributed according to the building statics from the Herchenbach modular system, the aluminium buildings are stable and safe in different wind load zones. Buildings from Herchenbach can withstand wind loads of up to 1.71 kN/m².
How does the wind load affect the anchoring of the building?
Lightweight buildings made of aluminium are significantly lighter than steel or reinforced concrete buildings of the same size, while being more stable. Anchoring on existing surfaces with ground spikes is possible in many cases. In addition to the building size, the wind load zone also determines the length, diameter and number of ground spikes used. Anchoring with heavy-duty dowels is another option. Building without foundations not only saves costs of around €100,000 per 1000 m² of hall; the construction time is also shortened by at least four weeks.
Lightweight buildings from Herchenbach combine the safety aspects of the legally applicable standards, which are the same for all buildings (regardless of whether they are steel, concrete or masonry constructions) with the demand for a variable warehouse or logistics building into one simple and cost-effective solution. The Herchenbach engineering departments have developed a flexible modular construction system using their experience gained from thousands of building construction projects. With four different aluminium profiles and high-strength alloys, buildings can be constructed in self-supporting widths from 5 m to a large building. The individual components are optimally calibrated to each other to offer optimum construction safety with minimum use of materials, while simultaneously ensuring assembly is as quick as possible. By selecting the appropriate profile thickness and suitable anchoring, Herchenbach lightweight buildings can be erected in different wind zones. Experts from Herchenbach determine the wind load to which your building will be exposed. They then plan the most cost-effective building for your needs and its wind load zone in collaboration with you. Approved structural analyses are available for over 500 building geometries, which can be used immediately. This ensures your new lightweight building can be built quickly and easily in different wind load zones.