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Wood Structure Hardwood Softwood.

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Presentation on theme: "Wood Structure Hardwood Softwood."— Presentation transcript:

1 Wood Structure Hardwood Softwood

2 Variability in wood products
Solid wood frequency strength

3 Variability in wood products
mean lower 5th percentile Solid wood ÷ safety factors frequency allowable design stress strength

4 Variability in wood products
mean mean lower 5th percentile ÷ safety factors Solid wood lower 5th percentile Wood composite A frequency ÷ safety factors strength allowable design stress allowable design stress

5 Anisotropy (St. Regis Paper Co.) (Indospectrum.com) (Côté)

6 Anisotropy Parallel to grain Perpendicular to grain

7 Wood sections/surfaces/planes
Longitudinal section Transverse section T T R R R R T T L L L T = tangential R = radial L = longitudinal

8 Anisotropy – perpendicular to grain
Radial Tangential

9 Hygroscopicity Hydrogen Bond  H  O  H H   O H Water 

10 Hygroscopicity Hydrogen Bond  H Wood O   H  O H 

11 Water in cell wall O H O H

12 Water in wood Free water Bound water Cell wall Cell lumen
Oven dry > Fibre saturation point 0% m.c – 30% m.c > 30% m.c.

13 Effect of moisture content on wood properties
Fibre Saturation Point

14 Comparative Environmental Impact Assessment Life Cycle Analysis
Canadian Wood Council

15 Comparative Environmental Impact Assessment
Canadian Wood Council


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