Item File 20477 Eurocode 1-3-A(1)

8/10/2019 Item File 20477 Eurocode 1-3-A(1)

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Eurocode 1- Actions on structures -

Part 1-3: General ActionsSnow loads

Dr.-Ing. Gerhard Scheuermann


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CONTENTS

General

Snow load on the ground and on roofs

Classification of actions

Design situations

Roof shape coefficient

Local effects

Exceptional snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow load

General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

National Annex (NA)

- values/and or classes where alternatives are given

in the Eurocodes

- values to be used where a symbol only is given- country specific data, e.g. snow map or a wind map

- the procedure to be used when alternative procedures are given

- decisions on the application of Informative Annexes

- reference to non-contradictory Annexes


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


This Part does not apply for sites at altitudes above 1500 m

- Advice for the treatment of snow loads for loads above

1500m may be given in the National Annex

- Based on local conditions an alternative altitude limit may be

given in the National Annex


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


This Part does not give guidance on specialistaspects of snow loading, for example:

- impact snow loads resulting from snow sliding off orfalling from a higher roof

- the additional wind loads which could result from changesin shape or size of the building structure due to the

presence of snow or the accretion of ice

- loads in areas where snow is present all year round

- ice loading (see ISO 12494: Athmospheric icing of

structures)- snow loads on bridges

- lateral loading due to snow (e.g. lateral loads exerted bydrifts)


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps



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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

EUROCODE 1Part 1-3: Snow loadSnow load on the ground

Characteristic value(1) statistical model


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


Characteristic value

(1) statistical model

(2) annual maximum snow load

(3) characteristic snow load skhas a probability of 98%(=mean return once in 50 years)


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps



(4) characteristic snow load skhas a probability of98% (=mean return once in 50 years)

where:

sn is the ground snow load with a return period of n years

Pn is the annual probability of exceedance (equivalent to approximately1/n, where n is the corresponding recurrence interval

V is the coefficient of variation of annual maximum snow load

57722,01lnln6

1

5923,21

n

nk

PV

Vss


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps



- The characteristic value of snow load on the ground (sk)

should be in accordance with EN 1990

- The national Annex specifies the characteristic valuesto be used

- To cover unusual local conditions the National Annex

may allow, for an individual project, the client and the

relevant authority to agree upon a different

characteristic value


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


Exceptional values of snow load sAD

- may be considered outside the usual statistical

methods if

sextr.> 1,5 sk,98%


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


Exceptional values of snow load sAD

- may be considered outside the usual statistical

methods

sextr.> 1,5 sk,98%

sAD= Ceslsk,98%

where:

sADis the design value of exceptional snow load on the ground for thegiven location

Ceslis the coefficient for exceptional snow loads; the recommended

value Cesl is 2,0


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

EUROCODE 1Part 1-3: Snow loadSnow load on roofs

Nature of load

caused by the propertiesof a roof- the shape of the roof

- its thermal properties

- the roughness of its surface- the amount of heat generated under the roof

- the proximity of nearby buildings

- the surrounding terrain

- the local meteorological climate, in particular its

windiness a..s.o.

Load arrangements- undrifted snow load on roofs

- drifted snow load on roofs


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

EUROCODE 1Part 1-3: Snow loadDesign situations

Load arrangements

for the persistent/transient design situations

s=iCeCtsk

for the accidental design situations where exceptionalsnow load is the accidental action

s=iCeCtsAd

for the accidental design situations where exceptional

snow drift is the accidental action

s=isk

where:

i is the snow load shape coefficient

Ce is the exposure coefficient (from 0,8 to 1,2)

Ct is the thermal coefficient (Ct= 1,0)


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General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


Snow loads shall be classified as variable, fixed

actions. They should be classified as static

actions:

1 1

,,0,""

1,1,""""

,,j i ik

QiiQk

QQ

PPjk

GjG

leading variable action sk

accompanying variable action sk


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Exceptional snow loads or exceptional snow

drifts can be treated as accidental actions:

1 1

,,2""

1,)(""""

, 1,21,1j i ikQik

QorAjk

G d

design value of exceptional snow load sAd

General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Representative values

combination value 0s

frequent value 1s

quasi-permanent value 2s

General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Roof shape coefficientsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow loadMonopitch roof


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow loadPitched roofs


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow loadMulti-span roofs


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow loadCylindical roofs

Roof shape coefficientGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

For 60 3= 0

For 60 3= 0,2 + 10h/b


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Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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EUROCODE 1Part 1-3: Snow loadRoof, abutting and close to taller structures


Snow load on

ground and roof

Design situations

Classificationof actions

coefficient

Local effects

Snow drifts

Snow load maps For 15 s= 0

For 15 s= 50% of snow load on adjacent slope

w= (b1 + b2) / 2h h / sk with = 2 kN/m

The recommended range of w is0,8 w 4

ls= 2h


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EUROCODE 1Part 1-3: Snow loadRoof, abutting and close to taller structures


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load mapsFor 15 s= 0

For 15 s= 50% of snow load on adjacent slope

w= (b1 + b2) / 2h h / sk with = 2 kN/m

The recommended range of w is0,8 w 4


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EUROCODE 1Part 1-3: Snow loadLocal effects

Drifting at projections and obstructionsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps 1= 0,8 2= h / skwith the restriction 0,8 22,0

= weight density for snow taken as 2 kN/m

lS= 2h

5 lS 15m


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Drifting at projections and obstructionsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Snow overhanging at the edge of a roofGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

se= k s /

= weight density for snow taken as 3 kN/m

k = 3 / d , but k d


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Snow loads on snow guards and other obstaclesGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

Fs= s b sin


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Exceptional snow drift

Multi-span roofsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

1

= 2h/sk

or 1

= 2b3

/ (ls1

+ls2

) or 1

= 5


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Snow driftsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Roofs, abutting and close to taller roofsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

ls= least value of

5 h or b1or 15m


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Roofs where drifting occurs at projections ,

obstructionsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

= least value of 2 h / sk or 5

ls= least value of 5 h or bi and h 1m

2b / ls


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Roofs where drifting occurs at parapetsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

= least value of 2 h / sk or 5

ls= least value of 5 h or bi and h 1m


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Snow Load Maps

European Climatic RegionsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Snow Load Maps

Altitude-Snow Load RelationshipsGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Snow Load Maps


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps


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Snow Load Maps


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

l d


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Snow Load Maps


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

OCO 1 1 3 S l d


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Snow Load Maps

Latvia republicGeneral

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

EUROCODE 1 P 1 3 S l d


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Snow Load Maps


Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

EUROCODE 1 P 1 3 S l d


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Snow Load Maps

General

Snow load on

ground and roof

Design situations

Classification

of actions

coefficient

Local effects

Snow drifts

Snow load maps

1,7 kN/m

1,7 kN/m

1,6 kN/m

1,5 kN/m

Item File 20477 Eurocode 1-3-A(1)

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Transcript of Item File 20477 Eurocode 1-3-A(1)