DOI QR코드

DOI QR Code

Effect of Test Zone Selection for Evaluating Bending Strength of Lumber

  • Pang, Sung-Jun (Dept. of Forest Sciences, College of Agriculture & Life Sciences, Seoul National University) ;
  • Lee, Jun-Jae (Dept. of Forest Sciences, Research Institute for Agriculture and Life Sciences, College of Agriculture & Life Sciences, Seoul National University) ;
  • Oh, Jung-Kwon (Dept. of Forest Sciences, Research Institute for Agriculture and Life Sciences, College of Agriculture & Life Sciences, Seoul National University)
  • 투고 : 2013.06.18
  • 심사 : 2013.09.24
  • 발행 : 2013.09.25

초록

This study investigated the effect of test zone selection for evaluating bending strength of visually graded lumber. This will contribute to the understanding of two different methods under different standards. In method I, the major defect was randomly placed in the test specimen. In method II, the major defect was randomly placed in the maximum moment zone (MMZ). The results showed that the method II is more accurate for reflecting the effect of defects governing the grade of lumber. Unless the maximum strength-reducing defect (MSRD) is placed in MMZ, the evaluated value would be higher than that of MSRD. For evaluating the modulus of rupture (MOR) of visually graded lumber in test set-up of Method I, the Eq. (5) needs to be considered.

키워드

참고문헌

  1. AS/NZS 4063.1 (2010) Characterization of structural timber part 1: test methods.
  2. AS/NZS 4063.2 (2010) Characterization of structural timber part 2: determination of characteristic values.
  3. ASTM D198 (2009) Standard test methods of static tests of lumber in structural sizes.
  4. ASTM D2915 (2010) Standard practice for sampling and data-analysis for structural wood and wood-based products.
  5. Barrett, J. D., W. Lau. Canadian lumber properties. Canadian Wood Council, 1994.
  6. BS EN 408 (2012) Timber structures - structural timber and glued laminated timber - determination of some physical and mechanical properties.
  7. Evans, J. W., D. E. Kretschmann, V. L. Herian. and D. W. Green. .2001. Procedures for developing allowable properties for a single species under ASTM D1990 and computer programs useful for the calculations. US Department of Agriculture, Forest Service, Forest Products Laboratory.
  8. KS F 2150 (2004) Method of static bending test for full sized structural lumber.
  9. KFRI notification 2009-1 (2009) Softwood structural lumber. Korea Forest Research Institute.
  10. ISO 13910 (2005) Structural timber - characteristic values of strength-graded timber - sampling, full-size testing and evaluation.
  11. Wang, Y., F. Lam, J. D. Barrett, and M. He. 2005. Comparisons of different test methods on bending properties of dimension lumber. Forest Prod. J. 55: 66-77.
  12. Wilks, S. S. 1941. Determination of sample sizes for setting tolerance limits. The Annals of Mathematical Statistics, 91-96.

피인용 문헌

  1. Determination of Grades and Design Strengths of Machine Graded Lumber in Korea vol.43, pp.4, 2015, https://doi.org/10.5658/WOOD.2015.43.4.446
  2. Analysis of Allowable Stresses of Machine Graded Lumber in Korea vol.43, pp.4, 2015, https://doi.org/10.5658/WOOD.2015.43.4.456