Laster2009 Enl Eurocode

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    Laster enligt Eurocode

    Byggnadskonstruktion AE2, ht 2009

    Appendix A: Combination of loads

    Appendix B: Imposed loadsAppendix C: Snow loads

    Appendix D: Wind loads

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    Appendix A: Combination of loads

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    September 2009

    Appendix A: Combination of loads

    Fundamental combination, ULS

    Characteristic combination, SLS

    Quasi-permanent combination, SLS

    Partial safety factors ffor permanentand variable loads (ULS and SLS)

    --1.01.0Accidental

    01.0

    1.01.0

    01.5

    1.01.35

    Fundamental

    favourableunfavourable

    Variable

    action q

    Permanent

    action g

    Variable

    action q

    Permanent

    action g

    SLSULSDesign

    situation

    ACTION 0 1 2

    Imposed load

    Categ. A, B

    Categ. C, DCateg. E

    0.7

    0.71.0

    0.5

    0.70.9

    0.3

    0.60.8

    Wind load 0.3 0.2 0

    Snow loadsk 3 kN/m

    2

    2.0 sk < 3.0 kN/m2

    1.0 sk < 2.0 kN/m2

    0.80.70.6

    0.60.40.3

    0.20.20.1

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    Appendix B: Imposed loads

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    September 2009

    Appendix B: Imposed loads

    =

    Imposed loads (ULS)

    A = 0.5 + 10/A[m2] 1for categories A D

    (0

    = 0.7)

    Imposed loads qkmay be reduced

    (for categories A-E) by

    applying a reduction

    factor A

    Imposed loads qkfrom more than two

    storeys may be reduced

    (for categories A-E) by

    applying a reduction

    factor n

    The reduction factors A and n must not be combined. For the design of floors and roofsA can be used. For structural members that carry imposed loads from several stories ncan be taken.

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    Appendix C: Snow loads EN 1991-1-3:2003 (BFS 2008:19)

    Characteristic snow values sk forsome Swedish town (urban) districts

    Alingss 2.0

    Arvika 2.5

    Bors 2.0-2.5

    Borlnge 3.0

    Falun 2.5-3.0

    Gllivare 3.0-4.5

    Gteborg 1.5

    Halmstad 1.5-2.5

    Haparanda 3.0

    Hofors 2.5

    Hrnsand 3.5

    Jokkmokk 3.0-4.5

    Jnkping 2.5-3.0Karlstad 2.5

    Kiruna 2.5-4.5

    Kunglv/Kungsbaka

    1.5

    Landskrona 1.0

    Lule 3.0

    Lund 1.5

    Malm 1.0

    Stockholm 2.0

    rebro 2.5

    stersund 2.0-3.5

    The upper values of the intervals apply to terrain in high places.

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    Appendix C: Characteristic value of snow load:

    S = i Ce Ct sk s =i sk

    sk characteristic value of snow on the ground,

    Ce exposure coefficient, should be taken as 1,0 unless otherwise specified for different

    topographies

    Ct thermal coefficient, high thermal transmittance (> 1 W/m2K), in particular for someglass covered roofs, because of melting caused by heat loss. For all other cases: Ct= 1,0

    i shape coefficients

    Monopitch roofs Pitched roofs

    Multi-span roofs

    0 15 30 45 60

    0.4

    0

    0.8

    1.6

    1.2

    i

    ()

    0 15 30 45 60

    0.4

    0

    0.8

    1.6

    1.2

    i

    )

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    Appendix C

    Roofs abutting to taller construction works

    1 = 0,8 (assuming the lower roof is flat)

    2 = S+W

    Shape coefficients

    2 = S+ W

    S

    due to sliding of snow from the upper roof

    W due to wind

    For 15 S = 0

    > 15 S = 0.5 () b/ls

    w = (b1 + b2)/2h h/sk

    where: is the weight density of snow, which may be taken as 2 kN/m3. 0.8 w 4

    The drift length: lS = 2h. The recommended restriction is 5 lS 15 m.

    (In Sweden 5 lS 10 m)

    b

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    September 2009

    Appendix C

    Drift against a wall

    Shape coefficients

    Drifting at projections and obstructions

    1 = 0,8 2 = h/sk

    With the restriction: 0,8 2 2,0The drift length: lS = 2h

    With the restriction is 5 lS 10 m

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    Appendix D1:Wind loads prEN 1991-1-4

    Wind forces

    The wind forces for the whole structure or a structural component should be determined: by calculating forces using force coefficients or by calculating forces from surface pressuresThe wind force Fw acting on a structure or a structural component may be determineddirectly by using:

    Fw= cs cdcfqp(ze)Aref

    where cs cdassume to be 1 and cf is the force coefficient for the structure or structuralelement.

    Wind pressure on surfaces

    Wind pressure combination of external (we) and internal (wi) pressures wnet = we wi

    External pressure: pecezpqew = Internal pressure: pii cizpqw =

    where: cpe and cpi are the pressure coefficients for the external and internal pressurerespectively

    The net pressure on a wall, roof or element is the difference between the pressures on theopposite surfaces taking due account of their signs. Pressure, directed towards the surfaceis taken as positive, and suction, directed away from the surface as negative. Examplesare given in Figure 5.1.

    Pressure on surfaces

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    September 2009

    Appendix D2

    ULS: ( )b

    qzeczpq = )( 2

    21

    bv

    bq =

    The recommended value for is 1.25 kg/m3. Reference wind speed vb in Sweden, see Appendix

    D2Terrain categories and terrain parameter

    Illustration of the exposure factor ce(z) for c0=1.0, kr=1.0

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    Appendix D3.

    Reference wind speed vb in [m/s] for Sweden

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    Appendix D4

    Internal pressure coefficients

    For a building with a dominant face the internal pressure should be taken as a fractionof the external pressure at the openings of the dominant face. The values given by Eq (7.2)and (7.3) should be used.When the area of the openings at the dominant face is twice the area of the openings inthe remaining faces,

    cpi = 0,75 cpe (7.2)When the area of the openings at the dominant face is at least 3 times the area of theopenings in the remaining faces,

    cpi = 0,9 cpe (7.3)where cpe is the value for the external pressure coefficient at the openings in the dominantface.

    For buildings without a dominant face, the internal pressure coefficient cpi should be

    determined from Figure 7.13, and is a function of the ratio of the height and the depth ofthe building, h/d, and the opening ratio for each wind direction , which should bedetermined from Eq (7.4).

    Figure 7.13 Internal pressure coefficients for uniformly distributed openings

    =

    openingsallofarea

    0,0-ornegativeiscwhereopeningsofarea pe

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    Appendix D5

    Reference height, ze, depending on h and b, and corresponding velocity pressure profile

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    Appendix D6Pressure coefficients on the external walls

    The values ofcpe,10and cpe,1 may be given in the NA. The recommended values are givenin Table below, depending on the ratio h/d. For intermediate values ofh/d, linear

    interpolation may be applied. The values of Table also apply to walls of buildings withinclined roofs, such as duopitch and monopitch roofs.

    For intermediate values ofh/d, linear interpolation may be applied.

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    Appendix D7Flat roofs

    Flat roofs are defined as having a slope () of 5< < 5

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    Appendix D8Flat roofs

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    Appendix D9 Monopitch roofs

    The roof, including protruding parts, should be divided into zones as shown in Figurebelow. The reference height ze should be taken equal to h.

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    Appendix D10

    Monopitch roofs

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    Appendix D11

    Duopitch roofs

    The roof, including protruding parts, should be divided into zones as shown in Figurebelow. The reference height ze should be taken equal to h.

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    Appendix D12

    Duopitch roofs

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    Appendix D13 Canopy roof

    A canopy roof is defined as the roof of a structure that does not have permanentwalls, such as petrol stations, dutch barns, etc.

    The degree of blockage under a canopy roof is shown in Figure 7.15. It depends onthe blockage , which is the ratio of the area of feasible, actual obstructions under thecanopy divided by the cross sectional area under the canopy, both areas being normal tothe wind direction. = 0 represents an empty canopy, and= 1 represents the canopy

    fully blocked with contents to the down wind eaves only (this is not a closed building).The overall force coefficients, cf, and net pressure coefficients cp,net, given in Tables

    7.6 to 7.8 for= 0 and= 1 take account of the combined effect of wind acting on boththe upper and lower surfaces of the canopies for all wind directions. Intermediate valuesmay be found by linear interpolation.

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    Appendix D14 Duopitch canopy

    Duopitch canopy (Table 7.7) the centre of pressure should be taken at the centre of eachslope (Figure 7.17). In addition, a duopitch canopy should be able to support one pitch withthe maximum or minimum load, the other pitch being unloaded.

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    Appendix D15

    + values indicate a net downward acting wind action; - values represent a net upward

    acting wind action