Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Performance Evaluation of Bending Strength of Curved Composite Glulams Made of Korean White Pine

잣나무 만곡 복합집성재의 휨강도 성능평가

  • Song, Yo-Jin (Department of Forest Biomaterials Engineering, College of Forest and Environmental Sciences, Kangwon National University) ;
  • Jung, Hong-Ju (Department of Forest Biomaterials Engineering, College of Forest and Environmental Sciences, Kangwon National University) ;
  • Lee, In-Hwan (Department of Forest Biomaterials Engineering, College of Forest and Environmental Sciences, Kangwon National University) ;
  • Hong, Soon-Il (Department of Forest Biomaterials Engineering, College of Forest and Environmental Sciences, Kangwon National University)
  • 송요진 (강원대학교 산림환경과학대학 산림바이오소재공학과) ;
  • 정홍주 (강원대학교 산림환경과학대학 산림바이오소재공학과) ;
  • 이인환 (강원대학교 산림환경과학대학 산림바이오소재공학과) ;
  • 홍순일 (강원대학교 산림환경과학대학 산림바이오소재공학과)
  • Received : 2015.06.10
  • Accepted : 2015.07.03
  • Published : 2015.07.25
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Abstract

In this study, to improve bending strength performance of Korean white pine, we made the curved composite glulam that was reinforced with glass fiber materials and larch lamina. Five types of Korean white pine curved glulams were made depending on whether they had been reinforced or not and how they had been reinforced. Type-A, reference specimen, was produced only with Korean white pine lamina, and Type-B was with larch lamina in the same thickness. Type-C was made by inserting a glass fiber cloth of textile shape between the each layer. Type-D was reinforced with two glass fiber cloths, which were placed inside and outside of the outermost lamina. Type-E was reinforced with GFRP sheet in the same way as Type-D. As a result of this bending strength test, the modulus of rupture (MOR) of Type-B, Type-C and Type-E were increased by 29%, 6%, and 48% in comparison with Type-A. However, MOR of Type-D was decreased by 2% in comparison with Type-A. In the failure modes, Type-A, Type-B and Type-C were totally fractured at the maximum load. However, load values of Type-D and Type-E decreased slowly because of reinforcement of fracture suppression, and the GFRP sheet (Type-E) had better reinforcing effect on compressive stress and tensile stress than the glass fiber cloth (Type-D).

본 연구에서는 잣나무 곡선부재의 휨 성능을 향상시키기 위하여 Glass fiber 소재의 보강재와 낙엽송 층재로 보강한 만곡 복합집성재를 제작하였다. 잣나무 만곡집성재는 보강유무 및 보강방법에 의하여 다섯 종류로 제작되었다. 대조시험편인 Type-A는 잣나무 층재로만 제작된 시험편이며, Type-B는 최외층에 잣나무 대신 동일한 두께의 국내산 낙엽송층재로 제작한 시험편이다. Type-C는 직물형태의 glass fiber cloth가 매 층재 사이에 삽입된 시험편이다. Type-D는 glass fiber cloth가 최외층재들의 안쪽과 바깥쪽에 2장씩 보강된 시험편이다. Type-E는 sheet 타입의 GFRP를 Type-D와 동일한 위치에 1장씩 보강한 시험편이다. 휨 강도 시험 결과, Type-A의 파괴계수와 비교하여 Type-B는 29%, Type-C는 6%, Type-E는 48% 증가되었으며 Type-D는 오히려 2% 감소하였다. 파괴모드에서 Type-A와 Type-B 그리고 Type-C는 최대하중에 도달하는 순간 완전히 파단되는 경향을 보였다. 그러나 Type-D와 Type-E는 보강재에 의해 파단이 억제되어 하중의 감소가 천천히 진행되었으며, 보강재 GFRP sheet(Type-E)는 압축응력과 인장응력에 대한 보강효과가 glass fiber cloth(Type-D)보다 양호한 것으로 확인되었다.

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References

  1. Chong, S.H., Park, B.S., 2008. Wood properties of the useful tree species grown in Korea. Korea forestry research institute, pp. 208-228.
  2. Gary M. Raftery, Annette M. Harte, 2011. Low-grade glued laminated timber reinforced with FRP plate. Composites: Part B 42, pp. 724-735. https://doi.org/10.1016/j.compositesb.2011.01.029
  3. Gary M. Raftery, Fiona Kelly, 2014. Composite elements of basalt fibre rods and low grade glulam. World conference on timber engineering (WCTE2014), pp. 1-10.
  4. Kim, K.H., Hong, S.I., 2011. Bonding performance of glulam reinforced with textile type of glass-and aramid-fiber, GFRP and CFRP. Journal of The Korean Wood Science and Technology 39(2): 156-162. https://doi.org/10.5658/WOOD.2011.39.2.156
  5. Korea forest service, 2014. Statical yearbook of forestry.
  6. Lim, H.M., Hong, S.H., Kang, H.Y., 2014. Investigation of the color change and physical properties of heat-treated pinus koraiensis square lumbers. Journal of The Korean Wood Science and Technology 42(1): 13-19. https://doi.org/10.5658/WOOD.2014.42.1.13
  7. Park, J.C., Shin, Y.J., Hong, S.I., 2009. Bonding performance of glulam reinforced with glass fiber-reinforced plastics. Journal of The Korean Wood Science and Technology 37(4): 357-363.
  8. Park, Y.G., Eom, C.D., Park, J.H., Chang, Y.S., Kim, K.M., Kang, C.W., Yeo, H.M., 2012. Evaluation of Physical Properties of Korean Pine (Pinus koraiensis Siebold & Zucc.) Lumber Heat-Treated by Superheated Steam. Journal of The Korean Wood Science and Technology 40(4): 257-267. https://doi.org/10.5658/WOOD.2012.40.4.257