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LVL Handbook Europe 		1
Foreword 3 		5
Contents 4 		6
1. LVL as a construction material 8 		10
1.1 Introduction 9 		11
1.1.1 LVL-P beams and columns - all veneers in the length direction 10 		12
1.1.2 LVL-C with cross-bonded veneers for robust structural panels 11 		13
1.2 Where can you use LVL 12 		14
1.3 Architect and structural designer appraisals of LVL 16 		18
1.4 History, volumes and raw materials of LVL 18 		20
1.4.1 History of the globally used engineered wood product LVL 18 		20
1.4.2 Material efficiency 20 		22
1.4.3 Wood species used in LVL 21 		23
1.4.4 Durable and inert gluing of LVL 21 		23
1.5 Sustainable building with LVL 21 		23
1.5.1 Traceable raw material and sustainable sources 21 		23
1.5.2 Sustainable over the life cycle 22 		24
1.5.3 Global warming impact of LVL 24 		26
1.5.4 Global warming impact of buildings 25 		27
1.6 Production of LVL 26 		28
1.6.1 Logs to blocks 26 		28
1.6.2 Blocks to veneer 27 		29
1.6.3 Drying and grading the veneer 28 		30
1.6.4 Layup and hot pressing 31 		33
1.6.5 Finishing 32 		34
1.6.6 Production summary 32 		34
1.7 Further processing 34 		36
1.7.1 Sanded surfaces: optical or calibration sanding 34 		36
1.7.2 Special cutting 34 		36
1.7.3 CNC Machining 34 		36
1.7.4 Edge profiling 36 		38
1.7.5 Surface treatments 36 		38
1.7.6 Multiple-glued members, GLVL 37 		39
1.7.7 Combined structures 38 		40
1.8 LVL sizes and layups 39 		41
1.9 Tolerances 41 		43
1.10 CE marking and certification of LVL products 42 		44
1.11 Design tools 43 		45
1.12 Basic properties of LVL 44 		46
1.12.1 Strength and stiffness properties 44 		46
1.12.2 Building physics properties 44 		46
1.12.3 Emissions and product safety 46 		48
1.12.4 Acoustics 46 		48
1.12.5 Fire safety 46 		48
1.12.6 Structures for seismic areas 46 		48
1.12.7 Visual properties of LVL surface 47 		49
1.12.8 Surface coating of LVL 48 		50
1.13 Joints between LVL panels 49 		51
2. LVL structures in floors, walls, roofs and in special applications 50 		52
2.1 General 51 		53
2.2 Floor structures 51 		53
2.2.1 Beam & joist floors 51 		53
2.2.2 Main beams for floors 56 		58
2.2.3 Rim boards and rim beams 58 		60
2.2.4 Panel structures 59 		61
2.2.5 Multiple-glued beams, GLVL 61 		63
2.2.6 Stressed-skin panels: rib panels, box panels or open box panels 61 		63
2.2.7 Renovation applications 65 		67
2.3 Roof structures 66 		68
2.3.1 Beam & rafter roofs 66 		68
2.3.2 Ridge beams 70 		72
2.3.3 Purlins 71 		73
2.3.4 Roof elements 73 		75
2.3.5 Roof panels 76 		78
2.3.6 Bracing panels 82 		84
2.3.7 Large LVL I-beams and box beams 82 		84
2.3.8 Roof renovation applications 83 		85
2.4 Wall structures 84 		86
2.4.1 Studs for timber frame walls 84 		86
2.4.2 Multiple-glued GLVL columns 86 		88
2.4.3 Lintels 87 		89
2.4.4 Integrated rim beams 88 		90
2.4.5 Ledger beams supports for floors or canopies 91 		93
2.4.6 Sole plates, bottom cords, top cords and top binders 92 		94
2.4.7 Window frame boards 92 		94
2.4.8 Bracing panels 92 		94
2.4.9 LVL-C panel walls 96 		98
2.5 Special structures 98 		100
2.5.1 Trusses and portal frames 98 		100
2.5.2 Doors and windows 101 		103
2.5.3 Reinforcement of old structures 102 		104
2.5.4 Stair cases 102 		104
2.5.5 Lift shafts of multi-storey buildings 103 		105
2.5.6 Extension of multi-storey buildings 103 		105
2.5.7 Bent and curved structures 104 		106
2.5.8 Bridges 		108
2.5.9 Other applications 107 		109
3. Purchasing, transport, handling and storage of LVL 108 		110
3.1 Purchasing LVL 109 		111
3.2 Transport, handling and storing of LVL 109 		111
3.3 Protecting the structure during construction 110 		112
3.4 Handling after use of LVL 111 		113
4. Structural design of LVL structures 112 		114
4.1 Basis of structural design 113 		115
4.1.1 Actions (Loads) 113 		115
4.1.2 Consequence class, reliability class and factor K_FI 114 		116
4.1.3 Load duration 115 		117
4.1.4 Service classes 115 		117
4.1.5 Partial safety factor of material Ym and modification factors k_mod and k_def 115 		117
4.1.6 Design resistance and stiffness 116 		118
4.2 Structural properties of LVL and strength classes 116 		118
4.2.1 Strength classes for LVL-P without crossband veneers 118 		120
4.2.2 Strength classes for LVL-C with crossband veneers 118 		120
4.3 LVL design according to Eurocode 5 120 		122
4.3.1 Bending 120 		122
4.3.2 Shear 121 		123
4.3.3 Tension parallel to the grain 122 		124
4.3.4 Tension perpendicular to the grain 122 		124
4.3.5 Compression parallel to the grain 122 		124
4.3.6 Compression perpendicular to the grain 123 		125
4.3.7 Bending stress at an angle to the grain 126 		128
4.3.8 Tension stress at an angle to the grain 126 		128
4.3.9 Stability of LVL members 127 		129
4.3.10 Notches 130 		132
4.3.11 Tapered beams 132 		134
4.3.12 Holes 134 		136
4.3.13 Serviceability limit state design: Deflections 136 		138
4.3.14 Serviceability limit state design: Floor vibrations 137 		139
4.4 Combined cross sections 138 		140
4.4.1 Theory 138 		140
4.4.2 Beams and columns 140 		142
4.4.3 Multiple-glued GLVL panels 141 		143
4.4.4 Rib slabs and box slabs 141 		143
5. Structural design of connections 142 		144
5.1 Design of LVL connections according to Eurocode 5 143 		145
5.2 Fastener spacing and edge and end distances 144 		146
5.3 Wood failure modes of connections 149 		151
5.3.1 Risk of splitting due to connection forces at an angle to the grain of face veneers 149 		151
5.3.2 Effective number of fasteners to prevent splitting or row shear 150 		152
5.3.3 Block shear and plug shear failure modes at multiple dowel-type steel-to-timber connections 151 		153
5.4 Nailed connections 152 		154
5.5 Screwed connections 153 		155
5.5.1 Laterally loaded screws in LVL 153 		155
5.5.2 Axially loaded screws 154 		156
5.5.3 Inclined screw connections 154 		156
5.6 Bolted and doweled connections 156 		158
5.7 Fastening LVL panels to frames 156 		158
5.8 Special cases 156 		158
6. Performance of LVL in fire 158 		160
6.1 Wood and fire 159 		161
6.2 Reaction to fire 159 		161
6.3 Fire protection ability, K-classes of coverings 160 		162
6.4 Fire resistance of LVL structures 160 		162
6.4.1 Fire resistance design process 160 		162
6.4.2 Charring rates of LVL 162 		164
6.4.3 Design of unprotected beams and panels 163 		165
6.4.4 LVL-C panel as a protection against fire exposure 165 		167
6.4.5 Summary of LVL-C panels for fire protection 165 		167
6.5 Fire resistance design of floor & wall structures with cavities 166 		168
7. Durability 168 		170
7.1 Service life of wooden buildings and LVL structures 169 		171
7.2 Durability classifications of structural LVL products 169 		171
7.2.1 Durability of adhesive bonding strength of structural LVL 169 		171
7.2.2 Biological durability of softwood LVL 169 		171
7.2.3 Structural LVL’s suitability for different use classes and service classes 169 		171
7.2.4 Discussion of durability class definitions 170 		172
7.3 Structural wood protection 170 		172
7.3.1 Resistance against temporary moisture exposure of structural LVL products 170 		172
7.3.2 Resistance against UV radiation 170 		172
7.3.3 Chemical durability 170 		172
7.4 Chemical wood protection 171 		173
7.4.1 Surface treatment 171 		173
7.4.2 Pressure impregnation 171 		173
8. Building physics 172 		174
8.1 LVL and moisture 173 		175
8.1.1 Moisture content of LVL 173 		175
8.1.2 Measuring the moisture content 173 		175
8.1.3 Dimensional changes due to moisture 175 		177
8.1.4 Water vapour resistance 176 		178
8.2 Thermal properties of LVL 176 		178
8.2.1 Influence of temperature on the mechanical properties of LVL 176 		178
8.2.2 Thermal conductivity of LVL products 176 		178
8.2.3 Temperature deformations 176 		178
8.2.4 Heat combustion and specific heat capacity 176 		178
8.2.5 Ignition temperature of LVL 177 		179
8.3 Airtightness 177 		179
9. Calculation examples of LVL structures 178 		180
9.1 LVL 48P joist floor 179 		181
9.2 Lintel over a window opening 184 		186
9.3 Double LVL 48 P ridge beam for roof 188 		190
9.4 Roof purlin 191 		193
9.5 Wall stud 195 		197
9.6 Axially loaded screw connection at the edge face 198 		200
9.7 Inclined screw connection 200 		202
9.8 Laterally loaded nail connection 203 		205
9.9 Hole in LVL beam 206 		208
9.10 Bracing of a stud wall 209 		211
9.11 Main beam of roof structure in 30min fire exposure 211 		213
10. References 214 		216
Disclaimer 222 		224
Notes 223 		225
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