4. STRUCTURAL DESIGN OF LVL STRUCTURES 4.2.1 Strength classes for LVL-P without crossband veneers For structural LVL made of spruce or pine the most relevant class is LVL 48 P for beam applications. LVL 32 P is suitable for stud applications where mechanical property requirements are lower. LVL 80 P is made from beech hardwood. The symbols of properties related to different directions of LVL are described in Table 4.4. Table 4.5. Strength classes for structural LVL-P without crossband veneers 15. 4.2.2 Strength classes for LVL-C with crossband veneers For structural LVL made of spruce or pine the most relevant class is LVL 36 C for load-bearing panels. LVL 25 C is suitable for panel applications where mechanical property requirements are lighter. LVL 70 C and LVL 75 C are made from beech hardwood. The symbols of properties related to different directions of LVL are described in Table 4.4. Table 4.5 Strenght class Property a Symbol Unit LVL 32 P LVL 35 P LVL 48 P LVL 50 P LVL 80 P Bending strength Edgewise, parallel to grain (depth 300 mm) fm,0,edge,k N/mm² 27 30 44 46 75 Flatwise, parallel to grain fm,0,flat,k N/mm² 32 35 48 50 80 Size effect parameter s - 0,15 0,15 0,15 0,15 0,15 Tension strength Parallel to grain (length 3 000 mm) ft,0,k N/mm² 22 22 35 36 60 Perpendicular to grain, edgewise ft,90,edge,k N/mm² 0,5 0,5 0,8 0,9 1,5 Compression strength Parallel to grain for service class 1 fc,0,k N/mm² 26 30 35 42 69 For service class 2 according to EN 1995-1-1 b 21 25 29 35 57 Perpendicular to grain, edgewise fc,90,edge,k N/mm² 4 6 6 8,5 14 Perpendicular to grain, flatwise (except pine) fc,90,flat,k N/mm² 0,8 2,2 2,2 3,5 12 Perpendicular to grain, flatwise, pine fc,90,flat,k,pine N/mm² DoP c 3,3 3,3 3,5 – d Shear strength Edgewise parallel to grain fv,0,edge,k N/mm² 3,2 3,2 4,2 4,8 8 Flatwise, parallel to grain fv,0,flat,k N/mm² 2,0 2,3 2,3 3,2 8 Modulus of elasticity Parallel to grain E0,mean e N/mm² 9 600 12 000 13 800 15 200 16 800 Parallel to grain E0,k f N/mm² 8 000 10 000 11 600 12 600 14 900 Perpendicular to grain, edgewise Ec,90,edge,mean g N/mm² DoP c DoP c 430 430 470 Perpendicular to grain, edgewise Ec,90,edge,k h N/mm² DoP c DoP c 350 350 400 Shear modulus Edgewise, parallel to grain G0,edge,mean N/mm² 500 i 500 i 600 650 760 Edgewise, parallel to grain G0,edge,k N/mm² 300 i 350 i 400 450 630 Flatwise, parallel to grain G0,flat,mean N/mm² 320 i 380 i 380 600 850 Flatwise, parallel to grain G0,flat,k N/mm² 240 i 270 i 270 400 760 Density ρmean kg/m³ 440 510 510 580 800 ρk kg/m³ 410 480 480 550 730 a Additional strength, stiffness and density properties not covered by the classes given in this table may be declared as individual values b Value may also be applied in Service Class 1 as a conservative value c Property is not expressed for the strength class but it may be given in the Declaration of Performance (DoP) of the LVL manufacturer d Class not produced from pine e Covering Em,0,edge,mean, Et,0,mean, Em,0,flat,mean, and Ec,0,mean f Covering Em,0,edge,k, Et,0,k, Em,0,flat,k, and Ec,0,k g Also covering Et,90,edge, mean h Also covering Et,90,edge,k i Property need not be tested if all other properties meet the minimum values for the strength class 118 LVL Handbook Europe
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