Vérification des ELS Déformation instantanée w_inst = w_(inst,g) + w_(inst,q) w_(inst,g)=(5〖∙g〗_(d,SLS)∙s∙L^4)/(〖384∙E〗_mean∙I)+〖〖6/5∙g〗_(d,SLS)∙s∙L〗^2/(〖8∙G〗_mean A)=2,76mm+0,61mm=3,36mm w_(inst,q)=(5〖∙q〗_(d,SLS)∙s∙L^4)/(〖384∙E〗_mean∙I)+〖〖6/5∙q〗_(d,SLS)∙s∙L〗^2/(〖8∙G〗_mean A)=5,33mm+1,18mm=6,51mm w_inst=3,36 mm+6,51 mm=9,9 mm Déformation finale w_(net,fin) = (1+k_def)∙w_(inst,g) + (1+ψ_2∙k_def)∙w_(inst,q) (4.73) Remarque : Pour la charge due à la neige dans l’Annexe Nationale finlandaise : ψ2 = 0,2. w_(net,fin) = (1+0,6)∙3,36 mm + (1+0,2∙0,6)∙6,51 mm = 12,7 mm Lorsque l’exigence est w_(net,fin)≤L/300=4000/300=13,3 mm→OK net,fin = (1+ def) ∙ inst,g + (1+ 2 ∙ def) ∙ inst,q (4.73) For the snow load in Finnish national annex: ψ2 = 0,2 net,fin = (1+0,6)∙ 3,36 mm + (1 + 0,2∙ 0,6)∙ 6,51 mm = 12,7 mm When the requirement is net,fin ≤ 300 =4 3 0 0 0 0 0 =13,3mm→OK 9. EXEMPLES DE CALCUL DE STRUCTURES EN LAMIBOIS , 226 (255) inst = 3,36 mm + 6,51 mm = 9,9 mm nal deflection net,fin = (1+ def) ∙ inst,g + (1+ 2 ∙ def) ∙ inst,q (4.73) Note: For the snow load in Finnish National annex: ψ2 = 0,2 net,fin = (1 + 0,6) ∙ 3,36 mm + (1 + 0,2 ∙ 0,6) ∙ 6,51 mm = 12,7 mm When the requirement is net,fin ≤ 300 , 4003000mm= 13,3mm → OK 4 Roof purlin ngle-span purlins of the roof of an unheated (service class 2) portal frame hall are 45x240 VL 48 P beams. Roof angle is 15°, span length is L = 4000 mm, spacing s = 900 mm and e purlins are perpendicular to the roof plane having a side support line at the middle of the an. Support length is 45mm. Snow load sk is 2,5 kN/m2 and own weight of the roof ucture is 0,30 kN/m2. For simplification there is no wind load in the example. The purlins e connected to the sides of the portal frame beams and they act also as lateral torsional ckling supports. Therefore the purlins have an axial load of Nk = 3 kN mainly from snow ad. = = 50,3 c,90,d = c,90,d ef = c,90,d ∙� support+15 mm� (4.14) c,90,d = 50,3kN 2∙ 51mm∙ (120mm + 15mm) = 3,7 N/mm2 c,90 ∙ c,90,edge,d = c,90 ∙ mod M ∙ c,90,edge,k =1,0∙ 0 1 , , 8 2∙ 6 N/mm2 = 4 N/mm2 c,90,d ≤ c,90 ∙ m,0,edge,d →OK (4.13) inst = inst,g + inst,q inst,g = 5∙ d,SLS ∙ ∙ 4 384∙ mean ∙ + 6/5∙ d,SLS ∙ ∙ 2 8∙ mean = 2,76mm + 0,61mm = 3,36mm inst,q = 5∙ d,SLS ∙ ∙ 4 384∙ mean ∙ + 6/5∙ d,SLS ∙ ∙ 2 8∙ mean = 5,33mm + 1,18mm = 6,51mm inst = 3,36 mm + 6,51 mm = 9,9 mm ELS ELS ELS ELS 190 Manuel sur le Lamibois (LVL) – Europe
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