Wind pressure on buildings

Accueil » Air & Wind » Wind pressure on buildings

EOLIOS takes care of the structure of your buildings:

Air & Wind

Continue navigation :

Our latest news :

Meet EOLIOS at Data Centre World Paris 2023!

Dater Center – Paris

CFD simulation for glassworks

CFD simulation: An alternative to wind tunnel testing

Pressure study

Our projects :

Prototype – Natural ventilation chimney

Tour Liberté – La Défense

Impact of wind on a solar power plant

Cooling towers – ICPE

Pedestrian comfort study – La Défense

Confort au Vent – PSG training center

Wind study – La Défense

Our areas of expertise :

Current standards for calculating pressures due to the impact of wind on facades

Eolios specializes in large-scale aeraulic studies.
This expertise enables us to provide you with an in-depth analysis of the actions of natural wind, and to provide guidelines for the design of buildings and civil engineering structures.

We refer to National Annex NF EN 1991-1-4 (Eurocode 1) to simulate and calculate wind pressures on the building, with a reference wind speed corresponding to an annual probability of exceedance equal to 0.02 (event with a return period equal to 50 years, i.e. W50).

When calculating the pressure on a façade, a large number of parameters need to be taken into account.
Wind speed seems obvious, but is precisely defined in the standard.
Other, more technical values are also important, such as the direction reduction coefficient. By convention, this direction is identified by the angle it forms with North, increasing clockwise from 0° to 360°.
Wind speeds are thus modulated according to certain predefined coefficients.
For temporary installations (marquees, etc.), the Cseason can be used to modulate wind coefficients according to the months in which the installation is used.

Identification of regulatory wind (class), site roughness criteria and simulation input data.

Definition Basic speed Vb
Cdir correction
Definition C0
Definition Cseason
Roughness coefficient definition
Defining other coefficients
Wind modelling at the domain entrance
Input synthesis

Other values are essential for this type of study, such as the terrain roughness coefficient.
This parameter varies according to the nature of the site.
The roughness imposed for calculations corresponds to the surrounding urbanization rate.
Indeed, the wind will not behave in the same way on totally open ground as on densely urbanized land.
The reference values are defined in several classes. There are 5 different classes, depending on whether the site is at sea, in open country, in the countryside with scattered dwellings, in an urbanized or industrial area, or in a densely urbanized area.

The precise definition of Eurocode input parameters ensures that calculations comply with the laws in force for this type of study.

The following video presents a CFD project linked to the modeling of the distribution of aeraulics within a city and the impact that air can have on facades. This project covers a range of applications focusing on the evolution of aeraulics over time, enabling us to quantify the evolution of pressures as well as the evolution of air flows in the city.
The main objective of many of these analyses is the impact of wind on structures, in order to validate dimensioning and check thatno undesirable effects occur in the future.

Play Video

CFD calculation of wind pressure coefficients

Each wall of a building is exposed to the wind on both sides (outside and inside).
The pressure exerted by the wind on the building is either attenuated or amplified, depending on the extent of the surface receiving the wind, the openings and its impact on the faces (overpressure or underpressure).
For any structure, it is advisable to determine both effects: external pressure and internal pressure.

Why is CFD necessary to study the impact of wind on facades?

The use of CFD is becoming increasingly common in this type of study.
Indeed, during the various design phases, it can happen that external elements are not taken into account.

An error or parameter not taken into account can have devastating consequences once the building has been constructed.
Take, for example, the accident that occurred on February 18, 2022, when part of the roof of London’s O2 Arena collapsed.
This accident occurred because the design teams failed to take into account the possibility of a strong Venturi effect. could be created between the two neighbouring towers. CFD modeling would have verified the design and highlighted this phenomenon.

Today, simulation provides a fast, low-cost response to such challenges.
CFD allows you to secure your projects and limit the occurrence of problems during operation.