Bending properties of dimension lumber produced from Siberian larch (Larix sibirica) in Mongolia

Bayasaa Tumenjargal,Jyunichi Ohshima,Shinso Yokota,Futoshi Ishiguri,Bayartsetseg Baasan,Ikumi Nezu,Ganbaatar Chultem,Haruna Aiso-Sanada,Yusuke Takahashi

doi:10.1186/s10086-020-01863-6

Abstract

The modulus of elasticity (MOE) and modulus of rupture (MOR) were evaluated for 190 pieces of dimension lumber (2 by 4 lumber, 38 by 89 mm in cross-section) produced from Larix sibirica trees grown in Mongolia. The 5% tolerance limits of the MOE and MOR were 5.70 GPa and 15.1 MPa, respectively. The value of the 5% tolerance limit of the MOR exceeded the characteristic value of 2 by 4 lumber in visual grading class No. 3 of the Japanese Agricultural Standard for the D. fir-L, Hem-Tam, JS-III and S-P-F softwood species groups. A significant positive correlation was found between the MOE and MOR, although air-dry density was weakly correlated with bending properties in L. sibirica.

Highlights

Structural lumber is one of the world’s main construction materials, and graded lumber is the highest value product from trees [1]
The value of the 5% tolerance limit of the modulus of rupture (MOR) exceeded the characteristic value of the MOR of 2 by 4 lumber in visual grading class No 3 of the Japanese Agriculture Standard (JAS) for structural lumber for wood frame construction for the D. firL, Hem-Tam, S-P-F species groups, and JS-III (Table 2)
The MOR values of over 90% of the tested lumber in the present study fit the characteristic values of the MOR of 2 by 4 lumber in visual grading class No 1 or upper grade of the JAS for the D. fir-L, Hem-Tam, S-P-F, and JS-III species groups [31] (Table 2)

Summary

Introduction

Structural lumber is one of the world’s main construction materials, and graded lumber is the highest value product from trees [1]. Numerous studies have focused on mechanical properties, especially the modulus of elasticity (MOE) and modulus of rupture (MOR) in bending for structural lumber sawn from softwood species grown in plantations and natural forests [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19] Characteristic values, such as the lower tolerance limits of the MOE and MOR, are very important for structural lumber in construction [10, 13, 20,21,22]. França et al [22] estimated allowable design bending strength for Southern pine (Pinus spp.) and found a value of 10.3 MPa for 2 by 4

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