HARMONISINGHARMONISING EUROPEANEUROPEANSNOW LOADS SNOW LOADS MAPPINGMAPPINGB.EiseltB.Eiselt, R.Peckham, G.Solomos, R.Peckham, G.SolomosISIS, JRC - Ispra (Italy)ISIS, JRC - Ispra (Italy)

"Scientific Support Activity in the field of Structural Stability of Civil "Scientific Support Activity in the field of Structural Stability of Civil Engineering Works related to Snow Loads”, financed by DGIII, lead by Engineering Works related to Snow Loads”, financed by DGIII, lead by

University of PisaUniversity of PisaConsortium: Italy, Germany, France, UK, Norway and Switzerland

FINAL GOAL

PROPOSAL FOR EUROCODESPROPOSAL FOR EUROCODES ROOF SNOW LOADROOF SNOW LOAD

CoverageCoverage:: 18 members of CEN - European Committee for Standardization (15 EU countries plus Switzerland, Norway and Iceland).

MAP OFMAP OF GROUND SNOW LOADSGROUND SNOW LOADS•Harmonised and European wide•Structural engineering design codes (Eurocodes)

•HARMONISED DATA:HARMONISED DATA:

maximum snow load, specific return interval (Project Partners)

•HARMONISED METHOD:HARMONISED METHOD:

SPATIAL EVALUATION OF THE DATA (JRC)

TASK OF JRCTASK OF JRC

IMPORTANCE of GIS:IMPORTANCE of GIS:

• error checking (reference system, double stations, errors in lon/lat)

• data managing• including other spatial information, esp. DTM, boundaries, rivers• spatial analysis• visualisation

Meteo Stations: Meteo Stations: 27862786 Maximum Yearly Snow Load / Snow Height Maximum Yearly Snow Load / Snow Height

Country No. Stations Min. no. of yrs Max. no. of yrs data

Austria 160 28 50 Belgium 13 11 31 Eire 14 30 58 … … … …

• convert snow height to snow load

• no of years of measurements

THE DATATHE DATA

MAPMAP SNOW LOAD - ALTITUDESNOW LOAD - ALTITUDE RELATIONSHIPRELATIONSHIP

• CLIMATIC REGIONSCLIMATIC REGIONS - similar climate

• ZONES:ZONES: specific snow load/ height relationship (curve curve fitting, interpolation, smoothing, reclassfitting, interpolation, smoothing, reclass)

• VALIDATIONVALIDATION check the results (meteorological stations, region boundaries).

METHODOLOGYMETHODOLOGY

SCOPE:SCOPE:

GROUPGROUP STATIONSSTATIONSSIMILAR SNOW LOAD/ALTITUDE RELATIONSHIP

CRITERIA:CRITERIA:• known climatic regionsknown climatic regions (as the 500 m height contour, a known boundary for rainfall patterns), • physical boundaries physical boundaries (sea…) • observed similar behaviourobserved similar behaviour of the data.

CLIMATIC REGIONSCLIMATIC REGIONS

Typical Altitude Function

s = snow load at altitude h

a = related to snow load at sea level

b = related to influence of the altitude

ZONE NUMBER ZONE NUMBER aa: characterise the snow load/altitude relationship

TWO PARAMETER FUNCTION:TWO PARAMETER FUNCTION:• Fix parameter “b” for the whole region - influence of altitude• Determine parameter “a” for every station - SL at sea level

CURVE FITTINGCURVE FITTING

0 500 1000 1500 2000 2500 3000

0

10

20

Alpine Region

Sn

ow

Lo

ad

(k

N/m

2)

Altitude (m)

2

1b

has

INTERPOLATIONINTERPOLATION

•INVERSE DISTANCE WEIGHTING (IDW)INVERSE DISTANCE WEIGHTING (IDW)

Classical Approach: Classical Approach: without buffer zones Revised Approach:Revised Approach: with BUFFER ZONESBUFFER ZONES

•SMOOTHING (mean filter):SMOOTHING (mean filter): eliminate microzones eliminate microzones

•RECLASSIFICATIONRECLASSIFICATION

RESULTSRESULTS

RESULTSRESULTS

VALIDATIONVALIDATION

•METEO STATIONS:METEO STATIONS: compare actual/calculated SL

• BORDERSBORDERS:: compare differences of snow load calculated according to the formulas of the confining climatic regionsformulas of the confining climatic regions.

Improves using BUFFER ZONESImproves using BUFFER ZONES

CONCLUSIONSCONCLUSIONS

• Harmonised European MapHarmonised European Map

• Importance of GISImportance of GIS

• Conversion to Administrative BoundariesConversion to Administrative Boundaries

• MaintenanceMaintenance– new data for existing countriesnew data for existing countries– extend to other countriesextend to other countries