Strength and Deformation of Pitched-Tapered Douglas-Fir Glued-Laminated Beams
Keywords:
<i>Pseudotsuga menziesii</i>, <i>Larix occidentalis</i>, size effectAbstract
Strength tests were conducted on 12 pitched-tapered beams. Four of these beams failed in radial tension, the estimated maximum stress levels ranging from 176 to 286 psi. The other beams failed in bending at the extreme fiber. In all cases, the load-deflection and load-strain responses were linear to failure under short-term loading conditions. The radial strengths were marginally acceptable at the allowable unit stress level currently assigned in Canada for tension perpendicular-to-the-grain. Other studies on size effect suggest that working stress levels should be governed by the volume of wood subjected to perpendicular-to-glueline tensile stress.References
Barrett, J. D. 1974. Effect of size on tension perpendicular-to-grain strength of Douglas-fir. Wood Fiber 6(2):126-143.nB.S.I. 1967. The structural use of timber. Brit. Std. Inst., Council for Codes of Practice, Brit. Std. Code of Practice CP112, London. 123 pp.nC.S.A. 1969. Structural glued-laminated timber. Can. Stand. Assoc., CSA 0122, Rexdale, Ont.nC.S.A. 1970. Code of recommended practice for engineering design in timber. Can. Stand. Assoc., CSA 086, Rexdale, Ont.nFoschi, R. O. 1968. Plane-stress problem in a body with cylindrical anisotropy, with special reference to curved Douglas-fir beams. Can. Dep. For. Rural Develop., Dep. Publ. No. 1244, Ottawa, Ont.nFoschi, R. O. 1970a. Point-matching analysis of curved timber beams. J. Struct. Div., A.S.C.E. 96(ST1):35-48.nFoschi, R. O. 1970b. CGLB: a computer program for the stress analysis of curved glued-laminated timber beams. Can. Dep. Fish. For., For. Prod. Lab., Inf. Rep. VP-X-61, Vancouver, B.C.nFoschi, R. O. 1971. Stresses in curved glued-laminated timber beams: experimental study. For. Prod. J. 21(7):42-48.nFoschi, R. O., and Selwyn P. Fox. 1970. Radial stresses in curved timber beams. J. Struct. Div., A.S.C.E. 96(ST10):1997-2008.nFox, Selwyn P. 1970a. Stress analysis of double-tapered pitched glued-laminated beams. Trans. Eng. Inst. Can. 13(A-2):I-VI, published in Eng. J. 53(3).nFox, Selwyn P. 1970b. Radial stresses in curved glulam members. Can. Consult. Eng. 12(8):37-38.nFox, Selwyn P. 1970c. Experimental verification of a stress analysis method for the double-tapered pitched glued-laminated beam. Can. Dep. Fish. For., For. Serv., Dep. Publ. No. 1277, Ottawa, Ont.nFox, Selwyn P. 1970d. Minimum-depth design of double-tapered pitched glued-laminated beams. Can. Dep. Fish. For., For. Prod. Lab., Inf. Rep. VP-X-73, Vancouver, B.C.nFox, Selwyn P. 1971. Revised tables of sizes for double-tapered pitched glued-laminated beams. Can. Dep. Environ., For. Serv., West. For. Prod. Lab., Inf. Rep. VP-X-86, Vancouver, B.C.nFox, Selwyn P. 1974. Strength and stiffness of laminated Douglas-fir blocks in perpendicular-to-glueline tension. Wood Fiber 6(2):156-163.nGopu, V. K. A., J. R. Goodman, M. D. Vanderbilt, M. E. Criswell, and J. Bodig. 1972. Analysis of double-tapered curved glued-laminated beams. Struct. Res. Rep. No. 9, Civil Eng. Dep., Colorado State Univ., Fort Collins, Colo.nHanrahan, Frank J. 1966. Radial stresses in curved rectangular glued-laminated members. Build. Stand. Mon., Int. Conf. Build. Off., Pasadena, Cal. July, 1966. pp. 13-16.nI.C.B.O. 1973. Uniform building code. Int. Conf. Build. Off., Whittier, Cal. Sect. 2511.nKennedy, Elma I. 1965. Strength and related properties of woods grown in Canada. Can. Dep. For. Publ. No. 1104, Ottawa, Ont.nKolb, Hans. 1969. Studies on the strength of end-jointed and curved structural parts of laminated wood. Translated from German by U.S. For. Serv., FPL-697, from Holz Roh-Werkst. 26(7):244-253.nMadsen, Borg. 1972. Duration of load tests for wood in tension perpendicular to grain. Struct. Res. Series, Rep. No. 7, Civil Eng. Dep., Univ. B.C., Vancouver, B.C.nNorris, C. B. 1963. Stresses within curved laminated beams of Douglas-fir. U.S. For. Serv., For. Prod. Lab., Res. Note FPL-020, Madison, WI.nN.F.P.A. 1973. National design specification for stress-grade lumber and its fastenings. Nat. For. Prod. Assoc., Wash., D.C.nThut, Walter K. 1970. Stresses in pitched-cambered glulam beams. Civil Eng. Dep., Univ. B.C., M.A.Sc. Thesis, Vancouver, B.C.nU.S.D.A. 1955. Wood handbook. U.S. Dep. Agr., For. Prod. Lab., Handb. No. 72, Wash., D.C.nWeibull, W. 1939. A statistical theory of the strength of materials. Proc. Roy. Swed. Inst. Eng. Res. No. 151.nWilson, T. R. C. 1939. The glued laminated wooden arch. U.S. Dep. Agr. Bull. No. 691, Wash., D.C.n
Downloads
Published
Issue
Section
License
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.
