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Ferenc Papp
Steel Buildings – Design of secondary elements
cL
purlin to be designed
3.2.2.2 Characteristic loads
Dead load
Self weight of purlin, external trapezoidal sheet, insulation and internal trapezoidal sheet
according to paragraph 2.1:
kN
p g := cL⋅ ( q tr.ext + q tr.int + q ins + qins.other) ⋅ cos ( α) + qpurlin⋅ cos ( α) = 1.212 ⋅
m
Snow load
Totally distrubuted snow load according to paragraph 2.2.1:
kN
2
p s := cL⋅ s ⋅ cos ( α) = 2.56⋅
m
Wind load
Pressure due to cross wind on zones F and G according to paragraph 2.3.3.1:
kN
- external wind effect
pw.e.pres := cL⋅ wFGH.0 = 0.109 ⋅
m
kN
- internal wind effect
pw.i.pres := −cL⋅ wi.0 = 0.22 ⋅
m
Sucking effect:
a) sucking due to cross wind according to paragraph 2.3.3.1:
- external wind effect
kN
zone F
pw.e.suck.F.a := cL⋅ wF.0.10 = −1.421 ⋅
m
kN
zone G
pw.e.suck.G.a := cL⋅ wG.0.10 = −1.093 ⋅
m
- internal wind effect: opposite to external wind effect, it is negligable
b) sucking due to the longitudinal wind according to paragraph 2.3.3.2:
- external wind effect
kN
zone F
pw.e.suck.F.b := cL⋅ wF.90.10 = −1.585 ⋅
m
zone H
zone I
pw.e.suck.H.b := cL⋅ wH.90.10 = −0.71 ⋅
pw.e.suck.I.b := cL⋅ wI.90.10 = −0.86 ⋅
kN
m
kN
m
- internal wind effect: opposite to the external wind effect, it is negligable
3.2.2.3 Design load combinations
Partial factors
dead load: γ G.sup := 1.35 γ G.inf := 1.0
snow load: γ s := 1.5
wind load: γ w := 1.5
Combination factor for wind effect Ψ w.0 := 0.6
Load combinations for two load cases
Load Combination 1 : " Pressure' effect
ppres.ULS := γ G.sup⋅ p g + γ s⋅ p s + Ψ w.0⋅ γ w⋅ ( p w.e.pres + p w.i.pres) = 8.23 ⋅
ppres.SLS := p g + p s + Ψ w.0⋅ ( p w.e.pres + p w.i.pres) = 5.658 ⋅
ppres.ULS ; ppres.SLS
13
kN
m
kN
m