Advertisement

Journal of Civil Structural Health Monitoring

, Volume 7, Issue 5, pp 627–635 | Cite as

A non-destructive method to determine the rotational stiffness of timber frame connections

  • Paul CrovellaEmail author
  • George Kyanka
Original Paper
  • 110 Downloads

Abstract

A method for non-destructive determination of the initial rotational stiffness of timber joints using the natural frequency of vibration of the beam is presented. The rotational stiffness of the joint is defined as “k”, and the bending stiffness of the member is defined as EI/L. The ratio of joint stiffness to the bending stiffness (k/EI/L or kL/EI) is defined as α. Previous researchers have found that for 1 < α < 100, the joint is semi-rigid, and the structural analysis should include joint rotational stiffness to limit stress calculation error to < 5%. The stiffness determined using the frequency of vibration was compared to stiffness determined using the measured deflection with a center-point loading. The relative deviation between the two, using the center point loading as a reference, was calculated. Twenty beams located in six buildings were tested, and 70% were found to have α > 1. The method accurately classified the joints as pinned or semi-rigid for 90% of the cases. The average percent relative deviation for the field-tested beams with α > 1 was 38%. Percent deviation for α > 1 could be reduced by almost half by taking a 5 mm diameter × 50 mm long sample for density testing. The probability distribution of the joint stiffnesses was characterized using a Weibull distribution. Errors due to assumptions about (1) equal stiffness of joints at each end, (2) existing stress in members, and (3) vibration damping were all studied. The relative impact of each on the results of the method is presented.

Keywords

Non-destructive testing Vibration and modal based techniques Structural monitoring of heritage buildings Structural analysis and modeling Field applications 

Notes

Acknowledgements

This work was funded in part by the US National Park Service (Grant no: P13AP00080).

References

  1. 1.
    Alexander A (2006) The Lhasa Jokhang—is the world’s oldest timber frame building in Tibet? Web J Cult Patrimony 1:123–154 (art 14) Google Scholar
  2. 2.
    O’Connor J (2004) Survey on actual service lives for North American buildings, Presented at woodframe housing durability and disaster Issues conference, Las Vegas, October 2004Google Scholar
  3. 3.
    Brungraber RL (1985) Traditional timber joinery: a modern analysis. PhD Dissertation, Stanford University, Palo Alto, CAGoogle Scholar
  4. 4.
    Ross RJ, Pellerin RF (1994) Nondestructive testing for assessing wood members in structures: a review. USDA Forest Products Laboratory General Technical Report FPL-GTR-70Google Scholar
  5. 5.
    Kasal B, Tannert T (2010) In situ assessment of structural timber. Springer, New York. doi: 10.1007/978-94-007-0560-9 Google Scholar
  6. 6.
    Lanata F (2015) Monitoring the long-term behaviour of timber structures. J Civil Struct Health Monit 5:167. doi: 10.1007/s13349-014-0095-2 CrossRefGoogle Scholar
  7. 7.
    Anthony RW (2008) Maintenance and rehabilitation—assessing and extending the life of existing wood structures. In: proceedings of structural engineering institute pre-congress workshop “wood engineering challenges in the new millennium: critical research needs”. American Society of Civil Engineers, Vancouver, BC, Canada, pp 110–126Google Scholar
  8. 8.
    Kasal B (2011) State-of-the-art in in situ evaluation of structural timber—some critical observations. In: Saporiti J (ed) Proceedings international conference on structural health assessment of timber structures 2011, Lisbon, PortugalGoogle Scholar
  9. 9.
    Cavalli A, Togni M (2015) Monitoring of historical timber structures: state of the art and prospective. J Civil Struct Health Monit 5:107. doi: 10.1007/s13349-014-0081-8 CrossRefGoogle Scholar
  10. 10.
    Fischetti D (2009) Structural investigation of historic buildings: a case study guide to preservation technology for buildings, bridges, towers and mills. Wiley, New YorkGoogle Scholar
  11. 11.
    Bulleit WM, Sandberg LB, Drewek MW, O’Bryant TL (1999) Behavior and modeling of wood-pegged timber frames. J Struct Eng 125(1):3–9CrossRefGoogle Scholar
  12. 12.
    Schmidt RJ, MacKay RB (1997) Timber frame tension joinery. Report on research sponsored by the Timber Frame Business Council. Washington, D.C.Google Scholar
  13. 13.
    Burnett D, Clouston P, Damery D, Fisette P (2003) Structural properties of pegged timber connections as affected by end distance. For Prod J 53(2):50–57Google Scholar
  14. 14.
    Miller J, Schmidt R, Bulleit W (2010) New yield model for wood dowel connections. J Struct Eng 136(10):1255–1261CrossRefGoogle Scholar
  15. 15.
    Anthony RW (2004) Condition assessment of timber using resistance drilling and digital radioscopy. APT Bull 35(4):21–26CrossRefGoogle Scholar
  16. 16.
    Morlier J, Bos F, Castéra P (2006) Diagnosis of a portal frame using advanced signal processing of laser vibrometer data. J Sound Vib 297(1–2):420–431CrossRefGoogle Scholar
  17. 17.
    Cai Z, Ross RJ, Hunt MO, Soltis LA (2002) Pilot study to examine use of transverse vibration nondestructive evaluation for assessing floor systems. For Prod J 52(I):89–93Google Scholar
  18. 18.
    Soltis LA, Wang X, Ross RJ, Hunt MO (2000) Vibration testing of timber floor systems. For Prod J 52(10):75Google Scholar
  19. 19.
    Wang X, Wacker J, Ross RJ, Brashaw BK, Vatalaro RJ (2005) Development of flexural vibration inspection techniques to rapidly assess the structural health of timber bridge systems. In: Proceedings of 14th international symposium on nondestructive testing of wood. University of Applied Sciences, Eberswalde, pp 113–121Google Scholar
  20. 20.
    Maille NJ (2008) Assessing the Roof Structure of the Breeding Barn Using Truss Member Resonant Frequencies, M.S. Thesis, University of Vermont, Burlington, VTGoogle Scholar
  21. 21.
    Laux S (2012) Estimation of axial load in timber beams using resonance frequency analysis. Masters Thesis, Chalmers University of Technology, Göteborg, SwedenGoogle Scholar
  22. 22.
    Irawan R, Priyosulistyo H, Suhendro B (2014) Evaluation of forces on a steel truss structure using modified resonance frequency. Proc Eng 95:196–203CrossRefGoogle Scholar
  23. 23.
    Blevins RD (2001) Formulas for natural frequency and mode shape. Krieger Pub Co., MalabarGoogle Scholar
  24. 24.
    McGuire J (1995) Notes on Semi-Rigid connections—finite element modeling continuous improvement. http://femci.gsfc.nasa.gov/semirigid/index.html. Accessed 10 Jan 2010
  25. 25.
    Pilkey WD (2005) Formulas for stress, strain, and structural matrices, 2nd edn. Wiley, New YorkzbMATHGoogle Scholar
  26. 26.
    American Forest and Paper Association (2015) National design specification for wood construction. American Wood Council, MadisonGoogle Scholar
  27. 27.
    Forest Products Laboratory (2010) Wood handbook—wood as an engineering material. General Technical Report FPL-GTR-190. Madison, WIGoogle Scholar
  28. 28.
    ANSYS® version 8.0 (2006) (computer software) ANSYS, Inc., CanonsburgGoogle Scholar
  29. 29.
    Crovella PL, Kyanka GH (2011). Use of vibration techniques to determine the rotational stiffness of timber joints. In: Proceedings of the structural health assessment for timber structures conference. LisbonGoogle Scholar
  30. 30.
    Minitab 17 Statistical Software (2010) (Computer software) Minitab Inc. State College PennsylvaniaGoogle Scholar
  31. 31.
    Lyu M, Zhu X, Yang Q (2017) Condition assessment of heritage timber buildings in operational environments. J Civil Struct Health Monit. doi: 10.1007/s13349-017-0239-2 Google Scholar
  32. 32.
    ASTM International (ASTM) (2006) Designation: D143-94 (Reapproved 2007) standard test method for small clear specimens of timber. ASTM, West ConshohockenGoogle Scholar
  33. 33.
    ASTM International (ASTM) (2006) Designation: D245-06 standard practice for establishing structural grades and related allowable properties for visually graded lumber. ASTM, West ConshohockenGoogle Scholar
  34. 34.
    Gorman DJ (1975) Free vibrations analysis of beams and shafts. Wiley, New YorkGoogle Scholar
  35. 35.
    Shaker FJ (1975) Effect of axial load on mode shapes and frequencies of beams. Lewis Research Center, NASA, ClevelandGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Department of Forest and Natural Resources ManagementState University of New York College of Environmental Science and ForestrySyracuseUSA

Personalised recommendations