Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지
DOI QR코드

DOI QR Code

Bending Creep of Glulam and Bolted Glulam under Changing Relative Humidity

  • PARK, Junchul (Production Management Team, KOAS CO. LTD.) ;
  • SONG, Yojin (Department of Forest Biomaterials and Engineering, College of Forest and Environmental Sciences, Kangwon National University) ;
  • HONG, Soonil (Department of Forest Biomaterials and Engineering, College of Forest and Environmental Sciences, Kangwon National University)
  • Received : 2020.06.25
  • Accepted : 2020.08.21
  • Published : 2020.09.25
Download PDF
⟨ Previous Next ⟩

Abstract

This study was carried out in order to evaluate the bending creep deflection of glulams and bolted glulams beam-to-beam connection with steel-gusset plates and bolts under changing relative humidity. The two types of glulam beams (130 mm in width, 175 mm in thickness, and 3000 mm in length) used in this study were made from domestic larch and composed of seven layers. The gussets were made of 8-mm-thick steel plates. Creep testing was conducted under constant loads in an uncontrolled environment. The test was carried out in a room that was well ventilated through a window. The creep test specimens were loaded for 33,000 hours. A bending creep test for the glulams was conducted through four-point loading. The applied stresses were 20% and 30% of the MOR in the static bending test for the glulam and bolted glulam, respectively. After 33,000 hours, the creep deflection of the glulam at a 20% stress level increased by 39% to 99%, while the creep deflection of the glulam at a 30% stress level increased by 27% to 67%, as compared with instantaneous elastic deflection. The relative creep increased during autumn and winter, and recovered during spring and summer. The relative creep of the bolted glulams was changed abruptly by loading up to 5,000 hours, but stabilized after 5,000 hours, and then gradually increased until 33,000 hours. The relative creep of the bolted glulam increased 2.11 times on average after 33,000 hours.

Keywords

References

  1. Aratake, S., Morita, H., Arima, T. 2011. Bending creep of glued laminated timber (glulam) using sugi (Cryptomeria japonica) laminae with extremely low Young's modulus for the inner layers. Journal of Wood Science 57(4): 267-275. https://doi.org/10.1007/s10086-011-1175-0
  2. Awaludin, A., Hirai, T., Hayashikawa, T., Sasaki, Y. 2008. Load-carrying capacity of steel-to-timber joints with a pretensioned bolt. Journal of Wood Science 54(5): 362-368. https://doi.org/10.1007/s10086-008-0962-8
  3. Bengtsson, C. 2001. Mechano-sorptive bending creep of timber-influence of material parameters. Holz als Roh-und Werkstoff 59(4): 229-236. https://doi.org/10.1007/s001070100217
  4. Bengtsson, C., Kliger, R. 2003. Bending creep of hightemperature dried spruce timber. Holzforschung 57(1): 95-100. https://doi.org/10.1515/HF.2003.015
  5. Byeon, J.W., Kim, T.H., Yang, J.K., Byeon, H.S., Park, H.M. 2017. Bending creep property of crosslaminated woods made with six domestic species. Journal of the Korean Wood Science and Technology 45(6): 689-702. https://doi.org/10.5658/WOOD.2017.45.6.689
  6. Chen, C.J., Lee, T.L., Jeng, D.S. 2003. Finite element modeling for the mechanical behavior of doweltype timber joints. Computers & Structures 81(30-31): 2731-2738. https://doi.org/10.1016/S0045-7949(03)00338-9
  7. Epmeier, H., Johansson, M., Kliger, R., Westin, M. 2007. Bending creep performance of modified timber. Holz als Roh-und Werkstoff 65(5): 343-351. https://doi.org/10.1007/s00107-007-0189-1
  8. Guan, Z., Rodd, P. 2001. DVW—Local reinforcement for timber joints. Journal of structural engineering 127(8): 894-900. https://doi.org/10.1061/(ASCE)0733-9445(2001)127:8(894)
  9. Hong, S.I., Park, J.C. 2006. Studies on evaluation for long-term structural performance of pinus densiflora Sieb. Et Zucc. (I): Shear creep and mechanosorptive behavior of drift pin jointed lumber. Journal of the Korean Wood Science and Technology 34(5): 11-18.
  10. Hunt, D.G. 1999. A unified approach to creep of wood. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 455(1991): 4077-4095.
  11. Lee, I.H., Song, Y.J., Hong, S.I. 2017. Evaluation of the moment resistance of reinforced wooden gusset to glulam joint. Journal of the Korean Wood Science and Technology 45(1): 53-61. https://doi.org/10.5658/WOOD.2017.45.1.53
  12. O'Ceallaigh, C., Harte, A., Sikora, K., McPolin, D. 2014. Mechano-sorptive creep of FRP reinforced laminated timber beams. Civil Engineering Research in Ireland, CERI 2014. Queen's University Belfast, 28-29 August 2014.
  13. Ranta-Maunus, A., Kortesmaa, M. 2000. Creep of timber during eight years in natural environments. In World Conference on Timber Engineering. Whistler, CA, Vol. 31.
  14. Sjödin, J., Johansson, C.J. 2007. Influence of initial moisture induced stresses in multiple steel-totimber dowel joints. Holz als Roh-und Werkstoff 65(1): 71-77. https://doi.org/10.1007/s00107-006-0136-6
  15. Sjödin, J., Johansson, C.J., Petersson, H. 2004. Influence of moisture induced stresses in steel-to-timber dowel joints. In Proceedings of the 8th world conference on timber engineering WCTE.
  16. Svensson, S., Toratti, T. 2002. Mechanical response of wood perpendicular to grain when subjected to changes of humidity. Wood Science and Technology 36(2): 145-156. https://doi.org/10.1007/s00226-001-0130-4
  17. Xu, B.H., Taazount, M., Bouchaïr, A., Racher, P. 2009. Numerical 3D finite element modelling and experimental tests for dowel-type timber joints. Construction and Building Materials 23(9): 3043-3052. https://doi.org/10.1016/j.conbuildmat.2009.04.00