5. STRUCTURAL DESIGN OF CONNECTIONS The characteristic block shear capacity of a timber member is calculated using the equation: F_(bt,k)=L_(net,t)∙t_1∙k_bt∙f_(t,0,k) (5.10) where Lnet,t is according to equation (5.8) kbt 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: 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 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: • without predrilled holes in softwood LVL or GLVL: f_(h,k)=(0,082 ∙ ρ_(k )∙ d^(-0,3))/(k_ • sin^2 β) [N/mm2] (5.13) • with predrilled holes in softwood LVL or GLVL f_(h,k)=(0,082 ∙ (1 - 0,01d) ∙ ρ_k)/(k_C ∙〖 (5.14) where ρk is the characteristic density, in kg/m³; β is the angle between nail axis and wide face; and d is the nail diameter, in mm. k_C {█(1 for LVL-P and GLVL-P@min{█ 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: k_ef=min{█(1@1-0,03(20-a_1/d) )┤ (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: • 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 t=max{█(7d@(13d-30) ρ_k/400)┤ ( 5.17) where t is the minimum thickness of timber member to avoid pre-drilling [mm] ρk is the characteristic timber density [kg/m³]; and d is the nail diameter [mm]. • Expression (5.17) may be disregarded for nails in the wide face of LVL-C or GLVL-C. • LVL or GLVL with nails in the edge face should be predrilled when the thickness of the member in nailing direction is smaller than t=max{█(14d@(13d-30)ρ_k/200)┤ (5.18) • Expression (5.17) may be replaced by expression (5.18) for edge distances a4 ≥ 14d • In axially loaded nail connections for smooth nails without predrilled holes and with a pointside penetration of at least 12d, the characteristic strength values of the withdrawal fax,k and pull-through fhead,k strengths [N/mm2] should be found from the following expressions 32 : fax,k = 20 ∙ 10-6 ∙ ρ k 2 for in the wide face of LVL and GLVL (5.19) fax,k = 0,32 ∙ d + 0,8 for in the edge face of LVL and GLVL with ρk ≥ 480kg/m3 (5.20) fhead,k = 70 ∙ 10-6 ∙ ρ k 2 (5.21) where ρk is the characteristic density kg/m3. However, smooth nails shall not be used to resist permanent or longterm axial loading. In the edge face of LVL-C and GLVL-C the minimum nail diameter d is 3mm. 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) 1,50, for solid wood and glued laminated timber and 1,25, for LVL; and 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 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) 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 = ( − 1) ∙ ( − ) ef = k ∙ h,0,k fh,0,k is the embedment strength according to subsection 5.5.1 or 5.6; n1 is the number of fasteners in rows parallel to the grain; 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) 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 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) 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 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: 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: 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 LVL Handbook Europe
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