Effect of growth ring width, pith and visual grade on bending properties of Chinese fir plantation dimension lumber

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• 作者：Jinghui Jiang (1)
  Jianxiong Lu (1)
  Haiqing Ren (1)
  Chao Long (1)
  
• 刊名：Holz als Roh- und Werkstoff
• 出版年：2012
• 出版时间：3 - January 2012
• 年：2012
• 卷：70
• 期：1
• 页码：119-123
• 全文大小：262 KB
• 参考文献：1. American Society for Testing and Materials D 1990-00 (2006) Standard practice for establishing allowable properties for visually-graded dimension lumber from in-grade test of full-size specimens 4(10):535-44
  2. American Society for Testing and Materials D 4761-05 (2006) Standard test methods for mechanical properties of lumber and wood-base structural material 4(10):535-44
  3. Bao F, Jiang Z (1998) Wood properties of main tree species from plantation China. China Forestry Publishing House, Beijing
  4. Barrett JD, Kellogg RM (1991) Bending strength and stiffness of second-growth Douglas-fir dimension lumber. For Prod J 41(10):35-3
  5. Barrett JD, Lau W (1994) Canadian lumber properties, Canadian wood council
  6. British standard, BS 4978 (2007) Visual strength grading of softwood. London, United Kingdom British Standards Institution
  7. China State Bureau of Technical Supervision GB1933-91 (1991) Method for determination of the density of wood. Standards press of China, Beijing
  8. Dunham RA, Cameron AD, Petty JA (1999) The effect of growth rate on the strength properties of sawn beams of silver birch. Scand J For Res 14:18-6
  9. Kretschmann DE, Evans JW (1999) Monitoring of visually graded structural lumber. Forest Products Laboratory, United States Department of Agriculture
  10. Moberg L (2000) Models of internal knot diameter for / Pinus sylvestris. Scand J For Res 15:177-87 CrossRef
  11. National lumber grades authority (NLGA) (2003) Standard grading rules for Canadian lumber. NLGA, British Columbia, Canada, pp?70-5, 182-83
  
• 作者单位：Jinghui Jiang (1)
  Jianxiong Lu (1)
  Haiqing Ren (1)
  Chao Long (1)
  
  1. Research Institute of Wood Industry, Chinese Academy of Forestry, Wan Shou Shan, Haidian, Beijing, 100091, China
  
• ISSN：1436-736X

文摘

According to NLGA standard grading rules, the dimension lumber of plantation Chinese fir was graded into four grades, i.e. SS, No.?1, No.?2 and No.?3. The bending strength and stiffness were determined according to ASTM D4761-05. The results showed that there was a significant difference in both MOE and MOR of the lumber with and without pith for SS and No.?2 grades, but this was not the case for No.?3 grade lumber. The mean MOE and MOR decreased as growth ring width (GRW) of each graded lumber increased. MOR and MOE of the SS and No.?2 grade dimension lumber with GRW<6?mm were significantly different from that of GRW??mm group. In regard to plantation Chinese fir, it is suggested that No.?2 and better grades should not have pith and the GRW must be less than 6?mm. For the lumber with pith and GRW??mm, it should be graded into No.?3 grade.