1. Strength Performance of Glulam made of Obi-sugi Laminae with low Young’s Modulus of Bending Miyazaki Prefectural Wood Utilization Research Center Akihiro Matsumoto, Hideki Morita, Yoshiyasu Fujimoto Atsushi Shiiba, Yutaka Iimura Miyazaki Prefectural Wood Utilization Research Center 2007 IUFRO All Division 5 Conference, Octorber 29th – November 2nd, 2007, Taipei

2. About Miyazaki Miyazaki Miyazaki Prefectural Wood Utilization Research Center Japan

3. Miyazaki Prefectural Wood Utilization Research Center About the standard of glulam in Japan The standard of structural glued laminated timber (Glulam) is regulated by Japanese Agricultural Standard (JAS) in Japan. What’s the JAS? The JAS is based on “The Law Concerning Standardization and Proper Labeling of Agricultural and Forestry Products”. The JAS standardize to regulate the quality of products, such as Agricultural, forestry, livestock and marine products including manufactured or processed products. Grade by machine rating Young’s modulus of bending （ GPa or 10 3 N/mm 2 ） The standard of laminae for structural glulam in JAS The standard of symmetric-structured glulam composed of different grade of laminae in JAS Strength grade Young’s modulus of bending （ GPa or 10 3 N/mm 2 ） MOR （ MPa or N/mm 2 ） AveLower limit

4. Miyazaki Prefectural Wood Utilization Research Center About 30% of laminae shows Young’s modulus less than 5.0GPa. These laminae will not meet JAS standards. The yield of qualifying laminae for structural glulam cut from obi-sugi log is extremely low and cost inhibited. Laminae’s distribution chart Specimens : Sugi(Japanese cedar) laminae grown in Miyazaki *MOE was measured with grading machine, and each lamina was classified by minimum MOE value in it Examine how to effectively utilize of lamina with low Young’s modulus Frequency(%)

5. Miyazaki Prefectural Wood Utilization Research Center Materials and methods

6. Miyazaki Prefectural Wood Utilization Research Center Profile of the finger-joint Length ： 14mm Width ： 3.8mm Top Width ： 0.51mm Bottom Width ： 0.3mm Angle ： 1/9.4 Adhesive ： Water-base poly-isocyanate resin adhesive Press pressure ： 10MPa lamina specimen Diagram of finger-joint (unit:mm) Grade by machine rating Young’s modulus of bending （ GPa or 10 3 N/mm 2 ） JAS laminae Non JAS laminae Five-grade machine stress graded obi-sugi laminae

7. Miyazaki Prefectural Wood Utilization Research Center Glulam specimen Grade by machine rating Young’s modulus of bending （ GPa or 10 3 N/mm 2 ） The standard of laminae for structural glulam JAS

8. Miyazaki Prefectural Wood Utilization Research Center 1.Bending test [Bending test C in JAS] Specimens dimension ： Width:120mm, Thickness:30mm, Length:800mm Test method ： 4 points bending test Distance between loading points : 210mm 、 Distance between fulcra : 630mm Loading speed ： 5mm/min Number of specimens : Each grade 130, Total 650 Test method of laminae

9. Miyazaki Prefectural Wood Utilization Research Center 2.Tensile test [Tensile strength test in JAS] Specimens dimension : Width:120mm, Thickness:30mm, Length:2,000 Number of specimens : Each grade 50, Total 250 3.Compression test [Strength test of structural lumber] Specimens dimension : Width:120mm, Thickness:30mm, Length:180mm Number of specimens : Each grade 50, Total 250 Test method of laminae

10. Miyazaki Prefectural Wood Utilization Research Center 1.Bending test [Bending test A in JAS] Specimens dimension : Width :120mm, Thickness :300mm, Length :6,000mm Test method : 4 points bending test Distance between loading points :1,200mm Distance between fulcra :5,400mm Number of specimens : Each type 8, Total 24 Test method of glulam

11. Miyazaki Prefectural Wood Utilization Research Center 2.Tensile test [Strength test of structural lumber] Specimens dimension : Width:105mm, Thickness:300mm, Length:2,000mm Number of specimens : Each type 12, Total 36 3.Compression test [Strength test of structural lumber] Specimens dimention : Width :120mm, Thickness :300mm, Length :720mm Number of specimens : Each type 8, Total 24 Test method of glulam

12. Miyazaki Prefectural Wood Utilization Research Center Result

13. Miyazaki Prefectural Wood Utilization Research Center Results of bending test for laminae The bending strength of L30 and L40 laminae were equal or over the standard strength of L50 laminae in JAS 5th%ile Lower limit 5th% ile: Lower 5% exclusion limits of the distribution assumed to be normal

14. Miyazaki Prefectural Wood Utilization Research Center Results of compression test for laminae The compression strength of L30 and L40 laminae were over the standard strength of L50 laminae in JAS 5th%ile

15. Miyazaki Prefectural Wood Utilization Research Center Results of tensile test for laminae The tensile strength of L30 and L40 laminae were over the standard strength of L50 laminae in JAS 5th%ile

16. Miyazaki Prefectural Wood Utilization Research Center Results of bending test for glulam 5th%ile The MOR of all glulam types were equal or over the standard strength of E65-F225 glulam in JAS

17. Miyazaki Prefectural Wood Utilization Research Center Results of compression test for glulam 5th%ile The compression strength of all glulam types were over the standard strength of E65-F225 in Building Standard Law Failure in the glulam began with a knot and a finger-joint

18. Miyazaki Prefectural Wood Utilization Research Center Results of tensile test for glulam Some of the specimens were slightly lower in tensile strength than that of E65-F225. 5th%ile Most of the specimens broke close to where they were chucked.

19. Miyazaki Prefectural Wood Utilization Research Center Conclusion

20. Miyazaki Prefectural Wood Utilization Research Center Strength Performance of Glulam made of Obi-sugi laminae with low Young’s Modulus of Bending Strength performance of laminae Strength performance of glulam As for the glulam made with composition of these lower Young’s modulus laminae, such as E65(using L40 laminae for inner layer), E55(L40 for inner layer) and E55(L30 for inner layer), the glulam performed well in bending and compression tests. The strength performances of laminae with lower Young’s modulus such as L30 and L40 were nearly equal to that of sugi wood with Young’s modulus of 5.0 kN/mm 2. Some specimens showed slightly lower tensile strength than that of E65-F225. It seems to be necessary to examine the strength performance of glulam made of laminae classified by average MOE value in it.

21. Miyazaki Prefectural Wood Utilization Research Center Strength Performance of Glulam made of Obi-sugi Laminae with low Young’s Modulus of Bending