5. DIMENSIONNEMENT DES ASSEMBLAGES t1 est l’épaisseur de l’élément en bois (t1 ≤ 2 tef). La capacité de cisaillement de bloc caractéristique d’un élément LVL-C est calculée à l’aide de l’équation suivante : F_(bt,k)=max{█(L_(net,t)∙t_1∙f_(t,0,k)+0,7∙L_ (v,k)@L_(net,t)∙t_1∙k_bt∙f_(t,0,k) )┤ (5.11) L_(net,v)=2∙(a_3+(n_1-1)∙(a_1-D)) (5.12) fv,k est la valeur caractéristique de la résistance au cisaillement parallèle au fil sur chant, pour le LVL 36 C fv,0,edge,k = 4,5 N/mm2 Les fournisseurs de Lamibois proposent également des instructions plus détaillées dans leur documentation technique. 5.4 ASSEMBLAGES PAR POINTES Les instructions relatives aux assemblages par pointes sont présentées dans la section 8.3 de l’Eurocode 5. Outre ces instructions, les instructions suivantes doivent également être prises en compte : • Les éléments en Lamibois doivent être pré-percés lorsque le diamètre d de la pointe dépasse 6 mm. • Pour les pointes d’un diamètre maximal de 8 mm disposés perpendiculairement au fil, les portances locales caractéristiques suivantes s’appliquent32 : • sans pré-perçage dans le Lamibois ou le GLVL résineux : f_(h,k)=(0,082 ∙ ρ_(k )∙ d^(-0,3))/(k_ • sin^2 β) [N/mm2] (5.13) • avec pré-perçage dans le Lamibois ou le GLVL résineux : f_(h,k)=(0,082 ∙ (1 – 0,01d) ∙ ρ_k)/(k_C ∙〖 (5.14) où ρk est la masse volumique caractéristique, en kg/m³ ; β est l’angle entre l’axe de la pointe et la de la largeur ; et d est le diamètre de la pointe, en mm. k_C {█(1 pour LVL-P et GLVL-P@min{█ pour LVL-C et GLVL-C┤ )┤ (5.15) • Pour éviter le mode de rupture par fendage, pour une file de n pointes parallèle au fil du bois, à moins que cette file ne soit en quinquonce d’une distance d’au moins 1d perpendiculairement au fil du bois, la capacité résistante parallèle au fil du bois (voir EC5, clause 8.1.2(4)) doit être calculée en utilisant le nombre efficace d’organes nef = nkef . kef dans le Tableau 8.1 de l’Eurocode 5 s’applique à la face de la largeur du LVL-P. Pour la face de la largeur du LVL-C kef = 1 et pour les faces de chant du LVL ou GLVL : k_ef=min{█(1@1-0,03(20-a_1/d) )┤ (5.16) • Pour les pointes lisses dans les trous avec pré-perçage dans la face de chant du Lamibois ou du GLVL, la longueur de pénétration de la pointe doit être d’au moins 12d. • Épaisseurs de l’élément en Lamibois : • Le LVL-P ou GLVL-P avec des pointes dans la face de la largeur doivent être pré-percés lorsque l’épaisseur des éléments en bois est inférieure à t=max{█(7d@(13d-30) ρ_k/400)┤ ( 5.17) où t est l’épaisseur minimale de l’élément en bois pour éviter le pré-perçage [mm] ρk est la masse volumique caractéristique du bois [kg/ m³] ; et d est le diamètre de la pointe [mm]. • L’expression (5.17) peut être ignorée pour les pointes dans la face de la largeur du LVL-C ou du GLVL-C. • Le Lamibois ou GLVL avec des pointes dans la face du chant doivent être pré-percés lorsque l’épaisseur de l’élément dans le sens du cloutage est inférieure à t=max{█(14d@(13d-30)ρ_k/200)┤ (5.18) • L’expression (5.17) peut être remplacée par l’expression (5.18) pour les distances de rive a4 ≥ 14d • Dans les assemblages à pointes soumis à une charge axiale, pour les pointes lisses sans pré-perçage et avec une pénétration de la pointe d’au moins 12d, les valeurs caractéristiques des résistances à l’arrachement fax,k et la résistance à l’enfoncement du côté de la tête fhead,k [N/mm2] doivent être déterminées à partir des expressions suivantes 32 : fax,k = 20 ∙ 10-6 ∙ ρ k 2 dans la face de la largeur du Lamibois et GLVL (5.19) fax,k = 0,32 ∙ d + 0,8 pour la face de chant du Lamibois et GLVL avec ρk ≥ 480 kg/m3 (5.20) fhead,k = 70 ∙ 10-6 ∙ ρ k 2 (5.21) où ρk est la masse volumique caractéristique en kg/m3. Cependant, les pointes lisses ne doivent pas être utilisées pour résister à une charge axiale permanente ou à long terme. Sur la face de chant des LVL-C et GLVL-C, le diamètre minimum des pointes d est de 3 mm. Les informations suivantes doivent être tirées de la DoP du fournisseur de pointes : • Moment d’écoulement plastique caractéristique My,k [Nmm] • Valeur caractéristique de la résistance à l’arrachement du côté de la pointe fax,k [N/mm2] d is the fastener diameter. The characteristic block shear capacity of a timber member is calculated using the equation: bt,k = net,t ∙ 1 ∙ bt ∙ t,0,k (5.10) where net,t is according to equation (5.8) 1,50, for solid wood and glued laminated timber and 1,25, for LVL; and t1 is the thickness of the timber member (t1 ≤ 2 tef). The characteristic block shear capacity of a LVL-C member is calculated using the equation: bt,k =max{ net,t ∙ 1 ∙ t,0,k +0,7 ∙ net,v ∙ 1 ∙ v,k net,t ∙ 1 ∙ bt ∙ t,0,k (5.11) net,v =2 ∙ ( 3 +( 1 −1) ∙ ( 1 − )) (5.12) fv,k is edgewise shear strength, for LVL 36 C fv,0,edge,k = 4,5 N/mm2 LVL suppliers have also more advanced instructions in their technical documentation. 5.4 Nailed connections Instructions for nailed connections are presented in Section 8.3 of Eurocode 5. In addition to those instructions, the following instructions shall also be taken into account: • LVL members shall be predrilled when the diameter d of the nail exceeds 6 mm • For nails with diameters up to 8 mm arranged perpendicular to the grain, the following characteristic embedment strengths apply 32: o without predrilled holes in softwood LVL or GLVL: h,k = 0,082 ∙ k ∙ −0,3 C ∙ cos2 + sin2 [N/mm2] (5.13) o with predrilled holes in softwood LVL or GLVL h,k =0,082 ∙ (1 − 0,01 ) ∙ k C ∙ cos2 + sin2 [N/mm2] (5.14) Where n2 is the number of fastener rows perpendicular to the grain; a1 is the fastener spacing parallel to the grain; a2 is the fastener spacing perpendicular to the grain; a3 is the fastener end distance; D is the hole diameter; ft,0,k is the tension strength of the timber member: 35 N/mm2 for LVL 48 P and 19 N/mm2 for LVL 36 C; fv,0,k is the shear strength of the timber member: fv,0,flat,k is 2.3 N/mm2 for LVL 48 P and 1.3 N/mm2 for LVL 36 C in flatwise connections; Rk is the characteristic load-carrying capacity per shear plane per fastener; and d is the fastener diameter. The characteristic block shear capacity of a timber member is calculated using the equation: bt,k = net,t ∙ 1 ∙ bt ∙ t,0,k (5.10) where net,t is according to equation (5.8) is 1,50 for solid wood and glued laminated timber and 1,25 for LVL; and t1 is the thickness of the timber member (t1 ≤ 2 tef). The characteristic block shear capacity of a LVL-C member is calculated using the equation: bt,k =max{ net,t ∙ 1 ∙ t,0,k +0,7 ∙ net,v ∙ 1 ∙ v,k net,t ∙ 1 ∙ bt ∙ t,0,k (5.11) net,v =2 ∙ ( 3 +( 1 −1) ∙ ( 1 − )) (5.12) fv,k is edgewise shear strength, for LVL 36 C fv,0,edge,k = 4,5 N/mm2 LVL suppliers have also more advanced instructions in their technical documentation. 5.4 Nailed connections Instructions for nailed connections are presented in Section 8.3 of Eurocode 5. In addition to those instructions, the following instructions shall also be taken into account: • LVL members shall be predrilled when the diameter d of the nail exceeds 6 mm • For nails with diameters up to 8 mm arranged perpendicular to the grain, the following characteristic embedment strengths apply 32: o without predrilled holes in softwood LVL or GLVL: h,k = 0,082 ∙ k ∙ −0,3 C ∙ cos2 + sin2 [N/mm2] (5.13) o with predrilled holes in softwood LVL or GLVL 182 (255) h,k = 0,082 ∙ (1 − 0,01 ) ∙ k C ∙ cos2 + sin2 [N/mm2] (5.14) where ρk is the characteristic density, in kg/m³ β is the angle between nail axis and wide face d is the nail diameter, in mm C{ 1 min{ or LVL − P and GLVL − P ( −2) 3 for LVL− C and GLVL − C (5.15) • To prevent splitting failure mode, for one row of n nails parallel to the grain, unless the nails of that row are staggered perpendicular to grain by at least 1d, the load-carrying capacity parallel to the grain (see EC5, clause 8.1.2(4)) should be calculated using the effective number of fasteners nef = nkef. kef in Table 8.1 of Eurocode 5 applies to LVL-P wide face. For LVL-C wide face kef = 1 and for LVL or GLVL edge face: ef =min{ 1 1 − 0,03(20 − 1/ ) (5.16) • For smooth nails in predrilled holes in the edge face of LVL or GLVL the pointside penetration length should be at least 12d • LVL member thicknesses: o LVL-P or GLVL-P with nails in the wide face should be pre-drilled when the thickness of the timber members is smaller than =max{ 7 (13 − 30) k 400 (5.17) where t is the minimum thickness of timber member to avoid pre-drilling [mm] 182 (255) ρk is the characteristic density, in kg/m³ β is the angle between nail axis and wide face d is the nail diameter, in mm C{ 1 pour LVL − P et GLVL − P min{ ( −2) 3 pour LVL − C et GLVL − C (5.15) • To prevent splitting failure mode, for one row of nnails parallel to the grain, unless the nails of that row are staggered perpendicular to grain by at least 1d, the load-carrying capacity parallel to the grain (see EC5, clause 8.1.2(4)) should be calculated using the effective number of fasteners nef, = nkef . kef in Table 8.1 of Eurocode 5 applies to LVL-P wide face. For LVL-C wide face kef = 1 and for LVL or GLVL edge face: ef =min{ 1 1 − 0,03(20 − 1/ ) (5.16) • For smooth nails in predrilled holes in the edge face of LVL or GLVL the pointside penetration length should be at least 12d • LVL member thicknesses: o LVL-P or GLVL-P with nails in the wide face should be pre-drilled when the thickness of the timber members is smaller than =max{ 7 (13 − 30) k 400 C{ 1 min{ or LVL − P and GLVL − P ( −2) 3 for LVL− C and GLVL − C • To prevent splitting failure mode, for one row of n nails parallel to the g nails of that row are staggered perpendicular to grain by at least 1d, the capacity parallel to the grain (see EC5, clause 8.1.2(4)) should be calcu effective number of fasteners nef, = nkef . kef in Table 8.1 of Eurocode 5 a wide face. For LVL-C wide face kef = 1 and for LVL or GLVL edge face: ef =min{ 1 1 − 0,03(20 − 1/ ) • For smooth nails in predrilled holes in the edge face of LVL or GLVL th penetration length should be at least 12d • LVL member thicknesses: o LVL-P or GLVL-P with nails in the wide face should be pre-drille thickness of the timber members is smaller than =max{ 7 (13 − 30) k 400 where t is the minimum thickness of timber member to avoid preρk is the characteristic timber density [kg/m³]; and d is the nail diameter [mm]. o Expression (5.17) may be disregarded for nails in the wide face GLVL-C. o LVL or GLVL with nails in the edge face should be pre-drilled w of the member in nailing direction is smaller than = max { 14 (13 − 30) k 200 o Expression (5.17) may be replaced by expression (5.18) for edg 14d • In axially loaded nail connections for smooth nails without predrilled ho pointside penetration of at least 12d, the characteristic strength values fax,k and pull-through fhead,k strengths [N/mm2] should be found from the expressions 32 : ax,k =20 ∙ 10−6 ∙ k2 for in the wide face of LVL and GLVL ax,k = 0,32 ∙ + 0,8 for in the edge face of LVL and GLVL wit head,k =70 ∙ 10−6 ∙ k2 where ρk is the characteristic density kg/m3. However, smooth nails sh resist permanent or long-term axial loading. The following information should be taken from the nail supplier’s Dop: C{ 1 min{ or LVL − P and GLVL − P ( −2) 3 for LVL− C and GLVL − C • To prevent splitting failure mode, for one row of n nails parallel to the grain, nails of that row are staggered perpendicular to grain by at least 1d, the load capacity parallel to the grain (see EC5, clause 8.1.2(4)) should be calculated effective number of fasteners nef, = nkef . kef in Table 8.1 of Eurocode 5 applie wide face. For LVL-C wide face kef = 1 and for LVL or GLVL edge face: ef =min{ 1 1 − 0,03(20 − 1/ ) • For smooth nails in predrilled holes in the edge face of LVL or GLVL the poin penetration length should be at least 12d • LVL member thicknesses: o LVL-P or GLVL-P with nails in the wide face should be pre-drilled wh thickness of the timber members is smaller than =max{ 7 (13 − 30) k 400 where t is the minimum thickness of timber member to avoid pre-drillin ρk is the characteristic timber density [kg/m³]; and d is the nail diameter [mm]. o Expression (5.17) may be disregarded for nails in the wide face of LV GLVL-C. o LVL or GLVL with nails in the edge face should be pre-drilled when th of the member in nailing direction is smaller than = max { 14 (13 − 30) k 200 o Expression (5.17) may be replaced by expression (5.18) for edge dis 14d • In axially loaded nail connections for smooth nails without predrilled holes an pointside penetration of at least 12d, the characteristic strength values of the fax,k and pull-through fhead,k strengths [N/mm2] should be found from the follow expressions 32 : ax,k =20 ∙ 10−6 ∙ k2 for in the wide face of LVL and GLVL ax,k = 0,32 ∙ + 0,8 for in the edge face of LVL and GLVL with ρk ≥ head,k =70 ∙ 10−6 ∙ k2 where ρk is the characteristic density kg/m3. However, smooth nails shall no resist permanent or long-term axial loading. The following information should be taken from the nail supplier’s Dop: ρk is the characteristic density, in kg/m³ β is the angle between nail axis and wide face d is the nail diameter, in mm C{ 1 min{ or LVL − P and GLVL − P ( −2) 3 for LVL− C and GLVL − C • To prevent splitting failure mode, for one row of n nails parallel to the grain, u nails of that row are staggered perpendicular to grain by at least 1d, the load capacity parallel to the grain (see EC5, clause 8.1.2(4)) should be calculated effective number of fasteners nef, = nkef . kef in Table 8.1 of Eurocode 5 applie wide face. For LVL-C wide face kef = 1 and for LVL or GLVL edge face: ef =min{ 1 1 − 0,03(20 − 1/ ) • For smooth nails in predrilled holes in the edge face of LVL or GLVL the poin penetration length should be at least 12d • LVL member thicknesses: o LVL-P or GLVL-P with nails in the wide face should be pre-drilled wh thickness of the timber members is smaller than =max{ 7 (13 − 30) k 400 where t is the minimum thickness of timber member to avoid pre-drillin ρk is the characteristic timber density [kg/m³]; and d is the nail diameter [mm]. o Expression (5.17) may be disregarded for nails in the wide face of LV GLVL-C. o LVL or GLVL with nails in the edge face should be pre-drilled when th of the member in nailing direction is smaller than = max { 14 (13 − 30) k 200 o Expression (5.17) may be replaced by expression (5.18) for edge dis 14d • In axially loaded nail connections for smooth nails without predrilled holes an pointside penetration of at least 12d, the characteristic strength values of the fax,k and pull-through fhead,k strengths [N/mm2] should be found from the follow expressions 32 : ax,k =20 ∙ 10−6 ∙ k2 for in the wide face of LVL and GLVL ax,k = 0,32 ∙ + 0,8 for in the edge face of LVL and GLVL with ρk ≥ head,k =70 ∙ 10−6 ∙ k2 where ρk is the characteristic density kg/m3. However, smooth nails shall no resist permanent or long-term axial loading. The following information should be taken from the nail supplier’s Dop: 152 Manuel sur le Lamibois (LVL) – Europe
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