Strength of OSB Scarf Joints in Tension

Authors

  • Ying H. Chui

Keywords:

Scarf joints, oriented strandboard, tensile strength, glued joints

Abstract

The use of scarf joints to join panel products can be found in structural applications such as wood I-joists and stress-skin panels. Design specifications for plywood scarf joints have been available for decades. Corresponding information on oriented strandboard (OSB) is not yet available despite its status as a suitable alternative to plywood as a structural panel product. This project was conducted to provide such design information. Three hundred joints were fabricated and tested in tension in a dry condition. These included two nominal thicknesses of OSB (11 mm and 18 mm) from two manufacturers. The adhesive used for the joints was a resorcinol formaldehyde. The joint strengths were compared with the material strengths in tension. The results showed that optimum joint strength was reached when the scarf slope was about 1 in 7 irrespective of manufacturer and thickness. At the optimum joint slope, no loss of strength was observed compared with unjointed material. For slopes less than the optimum slope, normalized joint strength decreased slightly. As the scarf slope increased from the optimum value, normalized joint strength decreased to a value of about 0.35 for a vertical scarf (butt) joint.

References

Canadian Standards Association (CSA). 1977. Resorcinol and phenol-resorcinol resin adhesives for wood (room- and intermediate temperature curing). CSA O112.7-M1977, Canadian Standards Association, Rexdale, ON.nCanadian Standards Association (CSA). 1993. OSB and waferboard. CSA O437.0-93, Canadian Standards Association, Rexdale, ON.nCanadian Standards Association (CSA). 1994. Engineering design in wood (limit states design). CSA O86.1-94, Canadian Standards Association, Rexdale, ON.nJessome, A. P. 1965. Research in Canada on end joints for laminated timbers. Proc. International Symposium on Joints in Timber. Timber Research and Development Association, Hughenden Valley, Bucks, UK.nJokerst, R. W. 1981. Finger-jointed wood products. Research Paper FLP 382, USDA Forest Products Laboratory, Madison, WI.nPatterson, T. J. 1964. Finger joints—Design and tests. Laboratory Report 100. American Plywood Association, Tacoma, WA.nRichards, D. B., and F. E. Goodrick. 1959. Tensile strength of scarf joints in southern pine. Forest Prod. J. 9(6): 177-179.n

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Published

2007-06-19

Issue

Number 1 / January 2000

Section

Research Contributions

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