Item File 20477 Eurocode 1-3-A(1)
Transcript of 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
EUROCODE 1Part 1-3: Snow load
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
EUROCODE 1Part 1-3: Snow load
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
EUROCODE 1Part 1-3: Snow load
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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
EUROCODE 1Part 1-3: Snow loadSnow load on the ground
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
EUROCODE 1Part 1-3: Snow loadSnow load on the ground
Characteristic value
(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
EUROCODE 1Part 1-3: Snow loadSnow load on the ground
Characteristic value
- 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
EUROCODE 1Part 1-3: Snow loadSnow load on the ground
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
EUROCODE 1Part 1-3: Snow loadSnow load on the ground
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
EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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
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 loadPitched roofs
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 loadMulti-span roofs
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 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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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
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EUROCODE 1Part 1-3: Snow loadRoof, abutting and close to taller structures
Roof shape coefficientGeneral
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
Roof shape coefficientGeneral
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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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
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EUROCODE 1Part 1-3: Snow loadLocal effects
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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EUROCODE 1Part 1-3: Snow loadLocal effects
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow loadCylindical roofs
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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EUROCODE 1Part 1-3: Snow load
Exceptional snow drift
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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EUROCODE 1Part 1-3: Snow load
Exceptional snow drift
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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EUROCODE 1Part 1-3: Snow load
Exceptional snow drift
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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
l d
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EUROCODE 1Part 1-3: Snow load
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
OCO 1 1 3 S l d
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EUROCODE 1Part 1-3: Snow load
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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EUROCODE 1Part 1-3: Snow load
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
EUROCODE 1 P 1 3 S l d
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EUROCODE 1Part 1-3: Snow load
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