Wood I-Joist Model Sensitivity to Oriented Strandboard Web Mechanical Properties


  • Jean-Frédéric Grandmont
  • Alain Cloutier
  • Guy Gendron
  • Richard Desjardins


Wood I-joists, web OSB, sensitivity analysis, numerical simulation


Research on wood I-joist design has often used laboratory testing, but simulation using the finite element method (FEM) offers advantages, including the possibility to separately study different joist components. The objective of this project was to perform a sensitivity analysis using FEM to determine which oriented strandboard (OSB) properties have higher impact on I-joist shear strain and deflection. OSB mechanical properties were changed from 50 to 200% of the reference value to determine their impact on web shear strain and I-joist deflection. The model was primarily sensitive to in-plane web shear stiffness, which changed I-joist deflection up to 23%. The model was also sensitive to the web tensile modulus of elasticity parallel and perpendicular to joist length and, to a lesser extent, to web shear stiffness. These properties changed I-joist deflection up to 2 and 1%, respectively. These findings will be used to plan future work to experimentally determine sensitive OSB web properties required to develop a finite element model of the mechanical behavior of wood I-joists.


Blanchet P, Gendron G, Cloutier A, Beauregard R. (2005) Numerical prediction of engineered wood flooring deformation. Wood Fiber Sci 37(3):484-496.nBodig J, Jayne BA. (1993) Mechanics of wood and wood composites. Krieger Publishing Company, Malabar, FL. 712 pp.nBoise Cascade (2009) All-joist specifier guide. Products guides and resources. http://www.bc.com/dms/wood/ewp/3_Guide_Resources/canada/alljoist_ca_spec_english_complete0/alljoist_ca_spec_english_complete.pdf'>http://www.bc.com/dms/wood/ewp/3_Guide_Resources/canada/alljoist_ca_spec_english_complete0/alljoist_ca_spec_english_complete.pdfnChui YH, Parade G, Shouyong L. (2005) Enhancing shear and bearing strength of wood I-joists. Report presented to the Value to Wood Program, Natural Resources Canada, University of New Brunswick. 78 pp.nChui YH, Wang Q, Pirzada G. (2007) Influence of OSB web stock properties on performance of wood I-joists. Report presented to the Value to Wood Program, Natural Resources Canada, University of New Brunswick. 63 pp.nFergus DA. (1979) Effect of web voids and stiffeners on the structural performance of composite beams. PhD thesis, Purdue University, West Lafayette, IN. 220 pp.nGrandmont J-F, Thivierge C, Cloutier A, Gendron G. (2006) Determination of engineering properties and modeling of wood I-joists. Page 269 in WCTE Proceedings, 6-10 August 2006, Portland, OR.nGuan ZW, Zhu E. (2004) Nonlinear finite element modeling of crack behavior in oriented strand board webbed wood I-beams with openings. J Struct Eng 130(10):1562-1569.nJessome AP. (1995) Résistance et propriétés connexes des bois indigènes au Canada. Forintek Canada Corp, Canada. 37 pp.nKaracabeyli E, Lau P, Henderson CR, Meakes FV, Deacon W. (1996) Design rated oriented strandboard in CSA standards. Can J Civil Eng 23(2):431-443.nMénard S. (1999) Poutrelles triangulées en bois, à membrures parallèles et diagonales aboutés comme système porteur principal de structures horizontales. PhD thesis, École Polytechnique Fédérale de Lausanne, Suisse. 142 pp.nMorris V, Gustaffson PJ, Serano E. (1996) The shear strength of lightweight beams with and without a hole—A preliminary study. Pages 199-214 in Wood mechanics: Workshop on mechanical properties of panel products, 22-23 March 1995, Watford, UK.nWeyerhaeuser (2009) #TJ-4500 Specifier's guide. Product literature. http://www.ilevel.com/literature/TJ-4500.pdf'>http://www.ilevel.com/literature/TJ-4500.pdfnZhu E. (2003) Modelling the structural behavior of OSB webbed timber I-beams. PhD thesis, University of Brighton, Brighton, UK. 159 pp.nZhu E, Guan ZW, Pope DJ, Rodd PD. (2005) Buckling of oriented strand board webbed wood I-joists. J Struct Eng 131(10):1629-1636.nZhu E, Guan ZW, Pope DJ, Rodd PD. (2007) Effect of openings on oriented strand board webbed wood I-joists. J Struct Eng 133(1):145-149.n






Research Contributions