| LVL Handbook Europe |
1 |
| Foreword |
5 |
| Contents |
6 |
| 1. LVL as a construction material |
10 |
| 1.1 Introduction |
11 |
| 1.1.1 LVL-P beams and columns – all veneera in the length direction |
12 |
| 1.1.2 LVL-C with cross-bonded veneers for robust structueal panels |
13 |
| 1.2 Where can you see LVL |
14 |
| 1.3 Architect and structural designer appraisals of LVL |
18 |
| 1.4 History, volumes and raw materials of LVL |
20 |
| 1.4.1 History of the globally used engineered wood product LVL |
20 |
| 1.4.2 Material efficiency |
22 |
| 1.4.3 Wood species udes in LVL |
23 |
| 1.4.4 Durable and inert gluing of LVL |
23 |
| 1.5 Sustainable building with LVL |
23 |
| 1.5.1 Traceable raw materialand sustainable sources |
23 |
| 1.5.2 Sustainable over the life cycle |
24 |
| 1.5.3 Global Warming impact of LVL |
26 |
| 1.5.4 Global impact of buildings |
27 |
| 1.6 Production of LVL |
28 |
| 1.6.1 Logs to blocks |
28 |
| 1.6.2 Blocks to veneer |
29 |
| 1.6.3 Drying and grading the veneer |
30 |
| 1.6.4 Layup and hot pressing |
33 |
| 1.6.5 Finishing |
34 |
| 1.6.6 Production summary |
34 |
| 1.7 Further processing |
36 |
| 1.7.1 Sanded surfaces: optical orcalibration sanding |
36 |
| 1.7.2 Special cutting |
36 |
| 1.7.3 CNC Machining |
36 |
| 1.7.4 Edge profiling |
38 |
| 1.7.5 Surface treatments |
38 |
| 1.7.6 Multiple-glued members, GLVL |
39 |
| 1.7.7 Combined structures |
40 |
| 1.8 LVL sixes and layups |
41 |
| 1.9 Tolerances |
43 |
| 1.10 CE marking and certification of LVL products |
44 |
| 1.11 Design tools |
45 |
| 1.12 Basic properties of LVL |
46 |
| 1.12.1 Strength and stiffness properties |
46 |
| 1.12.2 Building physics properties |
46 |
| 1.12.3 Emissions and product safety |
48 |
| 1.12.4 Acoustics |
48 |
| 1.12.5 Fire safety |
48 |
| 1.12.6 Structures for seismic areas |
48 |
| 1.12.7 Visual properties of LVL surface |
49 |
| 1.12.8 Surface coating of LVL |
50 |
| 1.13 Joints between LVL panels |
51 |
| 2. LVL structures in floors, walls, roofsand in special applications |
52 |
| 2.1 General |
53 |
| 2.2 Floor structures |
53 |
| 2.2.1 Beam & joist floors |
53 |
| 2.2.2 Main beams for floors |
58 |
| 2.2.3 Rim boards and rim beams |
60 |
| 2.2.4 Panel structures |
61 |
| 2.2.5 Multiple-glued beams, GLVL |
63 |
| 2.2.6 Stressed-skin panels: rib panels, box panels or open box panels |
63 |
| 2.2.7 Renovation applications |
67 |
| 2.3 Roof structures |
68 |
| 2.3.1 Beam & rafter roofs |
68 |
| 2.3.2 Ridge beams |
72 |
| 2.3.3 Purlins |
73 |
| 2.3.4 Roof elements |
75 |
| 2.3.5 Roof panels |
78 |
| 2.3.6 Bracing panels |
84 |
| 2.3.7 Large LVL I-beams and box beams |
84 |
| 2.3.8 Roof renovation applications |
85 |
| 2.4 Wall structures |
86 |
| 2.4.1 Studs for timber frame walls |
86 |
| 2.4.2 Multiple-glued GLVL columns |
88 |
| 2.4.3 Lintels |
89 |
| 2.4.4 Integrated rim beams |
90 |
| 2.4.5 Ledger beam supports for floors or canopies |
93 |
| 2.4.6 Sole plates, bottom cords, top cords and top binders |
94 |
| 2.4.7 Window frame boards |
94 |
| 2.4.8 Bracing panels |
94 |
| 2.4.9 LVL-C panel walls |
98 |
| 2.5 Special structures |
100 |
| 2.5.1 Trusses and portal frames |
100 |
| 2.5.2 Doors and windows |
103 |
| 2.5.3 Reinforcement of old structures |
104 |
| 2.5.4 Stair cases |
104 |
| 2.5.5 Lift shafts of multi-storey buildings |
105 |
| 2.5.6 Extension of multi-storey buildings |
105 |
| 2.5.7 Bent and curved structures |
106 |
| 2.5.8 Bridges |
108 |
| 2.5.9 Other applications |
109 |
| 3. Purchasing, transport, handlingand storage of LVL |
110 |
| 3.1 Purchasing LVL |
111 |
| 3.2 Transport, handling and storing of LVL |
111 |
| 3.3 Protecting the structure during construction |
112 |
| 3.4 Handling after use of LVL |
113 |
| 4. Structural design of LVL structures |
114 |
| 4.1 Basis of structural design |
115 |
| 4.1.1 Actions (Loads) |
115 |
| 4.1.2 Consequence class, reliability class and factor K_FI |
116 |
| 4.1.3 Load duration |
117 |
| 4.1.4 Service classes |
117 |
| 4.1.5 Partial safety factor of material γM and modification factors k_mod and k_def |
117 |
| 4.1.6 Design resistance and stiffness |
118 |
| 4.2 Structural properties of LVL and strength classes |
118 |
| 4.2.1 Strength classes for LVL-P without crossband veneers |
120 |
| 4.2.2 Strength classes for LVL-C with crossband veneers |
120 |
| 4.3 LVL design according to Eurocode 5 |
122 |
| 4.3.1 Bending |
122 |
| 4.3.2 Shear |
123 |
| 4.3.3 Tension parallel to the grain |
124 |
| 4.3.4 Tension perpendicular to the grain |
124 |
| 4.3.5 Compression parallel to the grain |
124 |
| 4.3.6 Compression perpendicularto the grain |
125 |
| 4.3.7 Bending stress at an angle to the grain |
128 |
| 4.3.8 Tension stress at an angle to the grain |
128 |
| 4.3.9 Stability of LVL members |
129 |
| 4.3.9.1 Members subjected to combined bendingand axial compression or tension |
129 |
| 4.3.9.2 Columns subjected to either compression orcombined compression and bending |
129 |
| 4.3.9.3 Beams subjected to either bending or combined bending and compression – Lateral torsional buckling (LTB) |
131 |
| 4.3.10 Notches |
132 |
| 4.3.11 Tapered beams |
134 |
| 4.3.12 Holes |
136 |
| 4.3.13 Serviceability limit state design: Deflections |
138 |
| 4.3.14 Serviceability limit state design: Floor vibrations |
139 |
| 4.4 Combined cross sections |
140 |
| 4.4.1 Basic principles |
140 |
| 4.4.2 Beams and columns |
142 |
| 4.4.3 Multiple-glued GLVL panels |
143 |
| 4.4.4 Rib slabs and box slabs |
143 |
| 5. Structural design of connections |
144 |
| 5.1 Design of LVL conections according to Eurocode 5 |
145 |
| 5.2 Fastener spacing and edge and end distances |
146 |
| 5.3 Wood failure modes of connections |
151 |
| 5.3.1 Risk of splitting due to connection forces at an angle to the grain of face veneers |
151 |
| 5.3.2 Effective number of fasteners to prevent splitting or row shear |
152 |
| 5.3.3 Block shear and plug shear failure modes at multiple dowel-type steel-to-timber connections |
153 |
| 5.4 Nailed connections |
154 |
| 5.5 Screwed connections |
155 |
| 5.5.1 Laterally loaded screws in LVL |
155 |
| 5.5.2 Axially loaded screws |
156 |
| 5.5.3 Inclined screw connections |
156 |
| 5.6 Bolted and doweled connectiond |
158 |
| 5.7 Fastening LVL panels to frames |
158 |
| 5.8 Special cases |
158 |
| 6. Performance of LVL in fire |
160 |
| 6.1 Wood and fire |
161 |
| 6.2 Reaction to fire |
161 |
| 6.3 Fire protection ability, K-classes of covering |
162 |
| 6.4 Fire resistance of LVL structures |
162 |
| 6.4.1 Fire resistance design process |
162 |
| 6.4.2 Charring rates of LVL |
164 |
| 6.4.3 Design of unprotected beams and panels |
165 |
| 6.4.4 LVL-C panel as a protection against fire exposure |
167 |
| 6.4.5 Summary of LVL-C panels for fire protection |
167 |
| 6.5 Fire resistance design of floor & wall structures with cavities |
168 |
| 7. Durability |
170 |
| 7.1 Service life of wooden buildings and LVL structures |
171 |
| 7.2 Durability classifications of structural LVL products |
171 |
| 7.2.1 Durability of adhesive bonding strength of structural LVL |
171 |
| 7.2.2 Biological durability of softwood LVL |
171 |
| 7.2.3 Structural LVL’s suitability for different use classes and service classes |
171 |
| 7.2.4 Discussion of durability class definitions |
172 |
| 7.3 Structural wood protection |
172 |
| 7.3.1 Resistance against temporary moisture exposure of structural LVL products |
172 |
| 7.3.2 Resistance against UV radiation |
172 |
| 7.3.3 Chemical durability |
172 |
| 7.4 Chemical wood protection |
173 |
| 7.4.1 Surface treatment |
173 |
| 7.4.2 Pressure impregnation |
173 |
| 8. Building physics |
174 |
| 8.1 LVL and moisture |
175 |
| 8.1.1 Moisture content of LVL |
175 |
| 8.1.2 Measuring the moisture content |
175 |
| 8.1.3 Dimensional changes due to moisture |
177 |
| 8.1.4 Water vapour resistance |
178 |
| 8.2 Thermal properties of LVL |
178 |
| 8.2.1 Influence of temperature on the mechanical properties of LVL |
178 |
| 8.2.2 Thermal conductivity of LVL products |
178 |
| 8.2.3 Temperature deformations |
178 |
| 8.2.4 Heat combustion and specific heat capacity |
178 |
| 8.2.5 Ignition temperature of LVL |
179 |
| 8.3 Airtightness |
179 |
| 9. Calculation examples of LVL structures |
180 |
| 9.1 LVL 48P joist floor |
181 |
| 9.2 Lintel over a window opening |
186 |
| 9.3 Double LVL 48 P ridge beam for roof |
190 |
| 9.4 Roof purlin |
193 |
| 9.5 Wall stud |
197 |
| 9.6 Axially loaded screw connection at the edge face |
200 |
| 9.7 Inclined screw connection |
202 |
| 9.8 Laterally loaded nail connection |
205 |
| 9.9 Hole in LVL beam |
208 |
| 9.10 Bracing of a stud wall |
211 |
| 9.11 Main beam of roof structure in 30min fire exposure |
213 |
| 10. References |
216 |
| Disclaimer |
224 |
| Notes |
225 |