Creosote Treatment Effect On Hardwood Glulam Beam Properties

Authors

  • Harvey B. Manbeck
  • Keith R. Shaffer
  • John J. Janowiak
  • Paul R. Blankenhorn
  • Peter Labosky
  • Randall T. Baileys
  • David A. Webb

Keywords:

Creosote treatment, hardwood, glulam beams, flexural strength, glueline shear strength, percent wood failure, preservative

Abstract

Flexure tests were conducted to determine the effect of creosote treatment on the performance of Combination A northern red oak, yellow poplar, and red maple glued-laminated (glulam) beams. This testing was conducted in accordance with ASTM D198-84 (ASTM 1987a), and the beams were fabricated in accordance with AITC 119-85 (AITC 1986), ANSI/AITC 190.1-83(AITC 1983b), and AITC 200-83 (AITC 1983a). Shear tests were also conducted on samples taken from the beams to determine the glueline shear strength and percent wood failure (WF).

There was no significant difference (P < 0.05) between the modulus of rupture (MOR) of creosote-treated and untreated northern red oak beams. However, the MORs of the creosote-treated red maple and yellow poplar beams were significantly (P < 0.05) higher than those for untreated beams. There was no significant difference (P < 0.05) between the treated and untreated apparent modulus of elasticity (MOE) of each species. Therefore, the post-fabrication creosote treatment process from 145.92 to 215.76 kg/m3 (9.11 to 13.47 pcf) average weight retention did not adversely affect the strength (MOR) or stiffness (MOE) of northern red oak, red maple, and yellow poplar Combination A glulam beams.

Glueline shear strengths for treated and untreated specimens of each species met or exceeded minimum performance criteria in AITC 200-83. Creosote treatment significantly (P < 0.05) increased glueline shear strength of red maple, but had no effect on the shear strength of red oak and yellow poplar specimens. Mean percentage wood failure of treated shear specimens was significantly (P < 0.05) greater than of untreated specimens in each species. Mean percentage wood failures of red oak and yellow poplar gluelines exceeded AITC 200-83 performance criteria; percentage wood failure of untreated (48%) and treated (59%) red maple shear specimens did not meet AITC 200-83 performance criteria.

References

American Institute of Timber Construction. 1983a. Inspection manual. AITC 200-83. American Institute of Timber Construction, Englewood, CO.nAmerican Institute of Timber Construction. 1983b. American national standards for wood products—structural glued laminated timber. ANSI/AITC A190.1-83. American Institute of Timber Construction, Englewood, CO.nAmerican Institute of Timber Construction. 1986. Standard specifications for hardwood glued laminated timber. AITC 119-85. American Institute of Timber Construction, Englewood, CO.nAmerican Society For Testing and Materials. 1987a. Standard methods of static testing for timbers in structural sizes. ASTM D198-84. American Society for Testing and Materials, Philadelphia, PA.nAmerican Society For Testing and Materials. 1987b. Standard methods for evaluating allowable properties for grades of structural lumber. ASTM D2915-86. American Society for Testing and Materials, Philadelphia, PA.nAmerican Society For Testing and Materials. 1987c. Standard methods for establishing stresses for structural glue laminated timber (glulam). ASTM 3737-87. American Society for Testing and Materials, Philadelphia, PA.nBarnes, H. M., and J. E. Winandy. 1986. Effects of seasoning and preservative on the properties of treated wood. 1986 Proceedings, Am. Wood Preserv. Assoc.: 95-104.nKilmer, W. R., Jr. 1992. Bondability of creosote treated hardwoods. M.S. thesis, School of Forest Resources, The Pennsylvania State University, University Park, PA. 105 pp.nKimmel, J. D., J. J. Janowiak, R. T. Baileys, and P. Merrick. 1994. Characteristics of creosote-treated LVL materials. Forest Prod. J. 44(5):49-53.nKoch, P. 1985. Utilization of hardwoods growing on southern pine sites. Agric. Handbook 605. United States Department of Agriculture, Washington, DC. 3, 710 pp.nManbeck, H. B., J. J. Janowiak, P. R. Blankenhorn, P. Labosky, R. C. Moody, and R. Hernandez. 1993. Performance of red maple glulam beams. Research Paper FPL-RP-519. USDA Forest Service, Forest Products Laboratory, Madison, WI.nSelbo, M. L. 1967. Long term effect of preservatives on glueline in laminated beams. Forest Prod. J. 17(5):23-32.nSelbo, M. L. 1975. Adhesive bonding of wood. Tech. Bull. No. 1012, United States Department of Agriculture, Washington, DC. 124 pp.nWaddell, K. L., D. D. Oswald, and D. S. Powell. 1989. Forest statistics of the United States, 1987. United States Department of Agriculture, Forest Service Research Bulletin PNW-RB-168. Portland, OR. 106 pp.nWinandy, J. E. 1988. Effects of treatment and redrying on mechanical properties of wood. Pages 54-62 in Margaret Hamel, ed. Wood protection techniques and the use of treated wood in construction. Proceedings 47358; October 28-30 1987, Memphis, TN. Forest Products Society, Madison, WI.nWinandy, J. E. 1987. Wood Handbook: Wood as an engineering material. Agric. Handbook 72. USDA Forest Service, Forest Products Laboratory. United States Department of Agriculture, Washington, DC. 466 pp.n

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Published

2007-06-19

Issue

Number 3 / July 1995

Section

Research Contributions

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