Visual grading criteria for Japanese larch (Larix kaempferi) structural timber from Spain

Abstract

Larch wood is structurally classified in many countries as one of conifers with the highest load-bearing capacity (strength class of C30). The Spanish visual classification regulation only assigns a strength class to 4 pine woods: Laricio pine (Pinus nigra Arn. var. Salzmannii), Silvestre pine (Pinus sylvestris L.), Radiata pine (Pinus radiata D. Don), and Pinaster pine (Pinus pinaster Ait.). This work adds to the number of structurally characterised species by creating a visual classification table for Japanese larch wood (Larix kaempferi (Lamb.) Carr.) which differentiates between 2 visual classes, MEG-1 and MEG-2. Characteristic strength values were calculated for each class (f _k,MEG-1 = 31.80 MPa, f _k,MEG-2 = 24.55 MPa), mean module of elasticity (E _0,mean,MEG-1 = 13,082 MPA, E _0,mean,MEG-2 = 12,320 MPA) and density (ρ _k,MEG-1 = 456.6 kg m⁻³, ρ _k,MEG-2 = 469.1 kg m⁻³), before finally assigning a strength class of C30 to visual class MEG-1, and a strength class of C24 to visual class MEG-2.

Keywords

Japanese larch wood / Visual grading / Strength class / Mechanical properties / Density

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