2x4 lumber of Korean pine was graded according to WWPA rules and tested in structural size. In grading of lumber as Structural Light Framing and Stud class, the proportion of No.2 and better grade lumber was 26%, and Stud class was 62% of all graded lumbers. Bending strength increased with increasing lumber grade and Stud class was higher than No.2 class lumber. This results were different to NDS data and should be considered in regulation of grading rules for domestic lumber Strength ratios of Korean pine were very similiar to WWPA rules except for No.3 class lumber. Allowable stresses of Korean pine 2 x 4s were higher than that of Douglas-fir and S-P-F in bending and these results showed that Korean pine can be used as structural materials. To establish the stress grading rules for domestic softwood lumber, U.S-standard and design specification are applicable in some cases, but also it should be considered understanding of domestic wood properties such as knot pattern and numbers appeared in each lumber. strength ratios. allowable stress values comparing to US standard grading rules.
1. 緖論
2. 材料 및 方法
3. 結果 및 考察
4. 結論
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