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Eurocodes Zoning

Snow, wind and seism zones for a building place

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- What are the Belgian wind zones ?
- How to adjust the basic wind velocity for each direction of wind and according to return period in Belgium ?
- Which are the terrain categories in Belgium ?
- Example of results given by the software
- Get the zones for a localisation using Eurocodes Zoning !

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On the map of the national annex, the Belgian area is divided into four wind zones.

Fundamental value of the basic wind velocity v_{b,0} | 23m/s | 24m/s | 25m/s | 26m/s |
---|

Wind zoning of Belgium (2010-2021)

A variation have to be considered with the probability factor c_{prob}.

When the wind comes from a direction where the probability of occurrence of strong winds is less, a reduction can be considered with the directional factor c_{dir}.

You should also take in account the effect of the roughness of the terrain (vegetation / urbanization) and the effect of orography (terrain relief) to accurately determine the peak velocity pressure for each wind direction.

- 0 - Sea or coastal area exposed to the open sea.
- I - Lakes or area with negligible vegetation and without obstacles.
- II - Area with low vegetation such as grass and isolated obstacles (trees, buildings) with separations of at least 20 obstacle heights.
- III - Area with regular cover of vegetation or buildings or with isolated obstacles with separations of maximum 20 obstacle heights (such as villages, suburban terrain, permanent forest).
- IV - Area in which at least 15% of the surface is covered with buildings and their average height exceeds 15m.

See the features of Eurocodes Zoning for wind analysis in Belgium

Available in English/French, otherwise «Google Translate»! ## B1 - Localization

## B2 - Elevations

## B3 - Building

## B4 - Terrain categories

## C1 - Snow NBN EN 1991-1-3 ANB (october 2007)

## C2 - Wind NBN EN 1991-1-4 ANB (december 2010)

^{*} The orography factor is calculated for a well individualized obstacle (an emergent zone compared to a general ground without marked relief) ## C3 - Seism NBN EN 1998-1 ANB (october 2011)

Available in English/French, otherwise «Google Translate»!

4.9053° , 50.2445°

688279m , 603864m

Rondchêne, 5500 Dinant, Wallonie

688279m , 603864m

Coordinates | 4.9013°, 50.241° | 4.9044°, 50.2436° | ||
---|---|---|---|---|

Elevations | 96m | 189m | ||

Obstacle effective height H | 93m | |||

Slope actual length L_{u} / L_{d} | 361.4m | |||

Slope angle Φ | 25.7% | |||

Horizontal distance site/top x | 121.2m | |||

Elevation at the place of construction | 197m |

common building with floors (apartments and/or office spaces)

100years

7.0m

35°

Sectors | 1 | 2 | 3 | 4 |
---|---|---|---|---|

Categories | II | II | III | II |

Radius R of the angular sector : 300m

Belgium (s_{k,0} = 0.5kN/m^{2})

Dinant, Namur

s_{k,197m} = 0.613 kN/m^{2}

s_{100ans} = 0.695 kN/m^{2}

24 m/s

Dinant, Namur

Belgium

Sectors | 1 | 2 | 3 | 4 |
---|---|---|---|---|

Sector definition | from 350° to 80° | from 80° to 170° | from 170° to 260° | from 260° to 350° |

Fundamental value of the basic wind velocity v_{b,0} | 24.0m/s | |||

Shape parameter K | 0.2 | |||

Exponent n | 0.5 | |||

Annual probability of exceedence p | 0.01 | |||

Probability factor c_{prob} | 1.038 | |||

Directional factor c_{dir} | 1.0 | 0.983 | 1.0 | 1.0 |

Basic wind velocity v_{b} | 24.9m/s | 24.5m/s | 24.9m/s | 24.9m/s |

Reference roughness length z_{0,II} | 0.05m | |||

Roughness length z_{0} | 0.05m | 0.05m | 0.3m | 0.05m |

Terrain factor k_{r} | 0.19 | 0.19 | 0.215 | 0.19 |

Height above ground z | 7.0m | |||

Minimum height z_{min} | 2.0m | 2.0m | 5.0m | 2.0m |

Roughness factor c_{r(z)} | 0.939 | 0.939 | 0.678 | 0.939 |

Obstacle type | cliffs | |||

Exposure type | - | - | downwind | - |

Factor depending on the type and dimensions of the obstacle s _{max} | 0.0 | 0.0 | 0.598 | 0.0 |

Orography factor^{*} c_{o(z)} | 1.0 | 1.0 | 1.308 | 1.0 |

Mean wind velocity v_{m(z)} | 23.4m/s | 23.0m/s | 22.1m/s | 23.4m/s |

Turbulence factor k_{l} | 0.995 | 0.995 | 1.247 | 0.995 |

Standard deviation of the turbulence σ_{v} | 4.713m/s | 4.634m/s | 6.696m/s | 4.713m/s |

Turbulence intensity I_{v(z)} | 0.201 | 0.201 | 0.303 | 0.201 |

Air density ρ | 1.25kg/m^{3} | |||

Exposure factor c_{e(z)} | 2.124 | 2.124 | 2.456 | 2.124 |

Peak velocity pressure q_{p(z)} | 824.7N/m^{2} | 797.5N/m^{2} | 953.3N/m^{2} | 824.7N/m^{2} |

Peak wind velocity for Serviceability Limit States v_{p(z),SLS} | 130.8km/h | 128.6km/h | 140.6km/h | 130.8km/h |

Peak wind velocity for Ultimate Limit States v_{p(z),ULS} | 160.2km/h | 157.5km/h | 172.2km/h | 160.2km/h |

1 (0.39m/s^{2})

Dinant, Namur

A seismic analysis may be required for this building.