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Snow zones map - Italy

What are the Italian snow zones ?

On the map of the national annex, the Italian territory is divided by provinces into three snow zones identified from 1 to 3. The snow zone 1 is subdivided into two to account for the Alpine or Mediterranean influence.

Zone I-M I-A II III
Characteristic value of snow on the ground without elevation sk,0 1.50kN/m2 1.50kN/m2 1.00kN/m2 0.60kN/m2

Eurocodes - Snow zones map - Italy (2010-2021) Snow zoning of Italy (2010-2021)

How to determine the influence of elevation on the ground snow load in Italy ?

Distinct variation laws must be applied depending on each zone.
Snow loads are calculated as follows:

How to adjust the ground snow load according to return period in Italy ?


Pn is the annual probability of exceedence :
dwl is the design working life, in years. Look at the design working life of buildings in Italy.

V is the coefficient of variation of annual maximum snow load with V=0.2 for a recurrence interval less than 50 years and V=0.6 for a recurrence interval greater than 50 years.

It should not be applied for annual probabilities of exceedence greater than 0,2 (i.e. return period less than approximately 5 years).

Example of results given by the software

See the features of Eurocodes Zoning for snow analysis in Italy
Available in English/French, otherwise «Google Translate»!

B1 - Localization

Italian flag
10.5188° , 43.7455°
Large map
Simple map
56011 Calci, Toscana

B2 - Elevations

Elevation map to calculate orography factor
Coordinates 10.5181°, 43.7303° 10.5198°, 43.7596° 10.5198°, 43.7596° 10.5179°, 43.7901°
Elevations 60m 798m 798m 109m
Obstacle effective height H 738m 689m
Slope actual length Lu / Ld 3261.4m 3379.8m
Slope angle Φ 22.6% 20.4%
Horizontal distance site/top x 1571.5m
Elevation at the place of construction 216m

B3 - Building

common structure
50years
10.0m
15°

B4 - Terrain categories

Terrain map
Sectors 1 2 3 4
Roughness classes C C B B
Radius R of the angular sector : 1000m
Coastline map of Italy
Sectors 1 2 3 4
Sector definition from 330° to 60° from 60° to 150° from 150° to 240° from 240° to 330°
Distance to shore > 100 km > 100 km 21.3 km 19.5 km
Exposure category III III III III

C1 - Snow UNI EN 1991-1-3 Appendice nazionale 24/09/2010

III (sk,0 = 0.6kN/m2)
Pisa,Toscana
sk,216m = 0.613 kN/m2

s50years = 0.613 kN/m2

C2 - Wind UNI EN 1991-1-4 Appendice nazionale 24/09/2010

3 (vb,0 = 27.0m/s)
Pisa, Toscana
Sectors 1 2 3 4
Sector definition from 330° to 60° from 60° to 150° from 150° to 240° from 240° to 330°
Value of the basic wind velocity from the map vb,0,map 27.0m/s
Elevation above which wind velocity increases a0 500m
Fundamental value of the basic wind velocity vb,0 27.0m/s
Shape parameter K 0.138
Exponent n 1.0
Annual probability of exceedence p 0.02
Probability factor cprob 1.0
Directional factor cdir 1.0 1.0 1.0 1.0
Basic wind velocity vb 27.0m/s 27.0m/s 27.0m/s 27.0m/s
Reference roughness length z0,II 0.05m
Roughness length z0 0.1m 0.1m 0.1m 0.1m
Terrain factor kr 0.2 0.2 0.2 0.2
Height above ground z 10.0m
Minimum height zmin 5.0m 5.0m 5.0m 5.0m
Roughness factor cr(z) 0.921 0.921 0.921 0.921
Obstacle type isolated hills
Exposure type downwind - upwind -
Factor depending on the type and dimensions of the obstacle s 0.444 0.0 0.282 0.0
Orography factor* co(z) 1.181 1.0 1.128 1.0
Mean wind velocity vm(z) 29.4m/s 24.9m/s 28.0m/s 24.9m/s
Turbulence factor kl 1.0 1.0 1.0 1.0
Standard deviation of the turbulence σv 5.4m/s 5.4m/s 5.4m/s 5.4m/s
Turbulence intensity Iv(z) 0.184 0.217 0.193 0.217
Air density ρ 1.25kg/m3
Exposure factor ce(z) 2.706 2.138 2.532 2.138
Peak velocity pressure qp(z) 1233.0N/m2 974.0N/m2 1153.8N/m2 974.0N/m2
Peak wind velocity for Serviceability Limit States vp(z),SLS 159.9km/h 142.1km/h 154.7km/h 142.1km/h
Peak wind velocity for Ultimate Limit States vp(z),ULS 195.8km/h 174.1km/h 189.4km/h 174.1km/h
* The orography factor is calculated for a well individualized obstacle (an emergent zone compared to a general ground without marked relief)