5. STRUCTURAL DESIGN OF CONNECTIONS Design splitting capacity is calculated from the characteristic splitting capacity according to equation (4.3), in subsection 4.1.6. For softwoods, the characteristic splitting capacity for the arrangement shown in Figure 5.9 should be taken as: F_(90,k)=14∙b√(h_e/((1 - h_e/h) )) [N] (5.3) (EC5 8.4) where F90,Rk is the characteristic splitting capacity [Ν]; he is the loaded edge distance to the centre of the most distant fastener [mm]; h is the timber member height, [mm]; and b is the member thickness, however, not more than the penetration depth of the fasteners [mm]. Equation (5.3) does not need to be checked for wide face (flatwise) LVL-C connections since it is not sensitive to splitting due to connection forces at an angle to the grain due to its cross veneers. 5.3.2 Effective number of fasteners to prevent splitting or row shear An effective number of fasteners nef shall be used for bolt, dowel and d > 12 mm screw connections at tension-loaded ends of LVL members to prevent splitting or row shear failure mode. For one row of ni fasteners parallel to the grain direction, the load-carrying capacity parallel to grain should be calculated using the effective number of fasteners nef according to the equation 31: n_ef=min{█(n_i@n_i^0,9 ∜((a ∙ t)/(50∙ 〖 (5.4) where ni is the number of fasteners in a row i; d is the effective diameter of the fastener, for screws def; a={█(min(a_1;a_3 ),when n_i≥2@a_3,when n_i=1)┤ (5.5) a1 is the spacing of fasteners in the grain direction; a3 is the end distance of fasteners; t={█(min(t_1;t_ connection with timber only in outer members @min( other two and multiple shear connection (5.6) t1 and t2 are the thicknesses of outer timber members (disregarded if the outer member is not timber); and ts is the thickness of the inner member of double shear connections or the smallest thickness of the inner member of a multiple shear connection. Figure 5.10. Row shear failure mode. Figure 5.8. Inclined force transmitted by a connection (modified from EC5 Figure 8.1). (Kuva_107_a splitting force in connections 190314, Kuva_107_b splitting force in connections 190314, Kuva_107_c splitting force in connections 190320) Design splitting capacity is calculated from the characteristic splitting capacity according to equation (4.3), in subsection 4.1.6. For softwoods, the characteristic splitting capacity for the arrangement shown in Figure 5.8 should be taken as: 90,k =14 ∙ √ ℎe (1 − ℎ ℎ e) [ ] (5.3) (EC5 8.4) where F90,Rk is the characteristic splitting capacity [Ν]; he is the loaded edge distance to the centre of the most distant fastener [mm]; h is the timber member height, [mm]; and b is the member thickness, however, not more than the penetration depth of the fasteners [mm]. Equation (5.3) does not need to be checked for wide face (flatwise) LVL-C connections since it is not sensitive to splitting due to connection forces at an angle to the grain due to its cross veneers. 5.3.2 Effective number of fasteners to prevent splitting or row shear An effective number of fasteners nef shall be used for bolt, dowel and d > 12 mm screw connections at tension-loaded ends of LVL members to prevent splitting or row shear failure mode. For one row of ni fasteners parallel to the grain direction, the load-carrying capacity parallel to grain should be calculated using the effective number of fasteners nef according to the equation 31: ef =min{ i i 0,9 √ ∙ 50∙ 2 4 (5.4) where ni is the number of fasteners in a row i; d is the effective diameter of the fastener, for screws def; ef =min� i i 0,9 � ∙ 50∙ 2 4 =�min( 1; 3),when i ≥2 3,when i =1 ef =min� i i 0,9 � ∙ 50∙ 2 4 =�min( 1; 3),when i ≥2 3,when i =1 =�min( 1; 2) connection with timber only in outer members min(2 1;2 2; s) other two and multiple shear connection 150 LVL Handbook Europe
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