Stochastic Damage Accumulation and Reliability of Wood Members
Keywords:
Creep rupture, damage models, load duration, reliability, woodAbstract
The mechanism leading to the reduction in strength of a wood member under sustained loads is one of creep rupture. Damage models have been developed to assess static damage accumulation in wood. Forms of these models are being used in reliability analyses of wood members and systems and in the development of probability-based design codes. Questions as to the validity of these models and the appropriateness of one or more of the models in the context of reliability studies have been raised. This paper presents the current state-of-the-art with respect to damage models for wood and offers observations concerning the limitations on the use of some of these models in reliability studies. Particular attention is paid to single members in flexure and the stochastic progressive accumulation of damage as predicted by the different models.References
Barrett, J. D., and R. O. Foschi. 1978a. Duration of load and failure probability in wood. Part I. Modelling creep rupture. Canadian J. Civil Eng. 5(4):505-514.nBarrett, J. D., and R. O. Foschi. 1978b. Duration of load and failure probability in wood. Part II. Constant, ramp, and cyclic loadings. Canadian J. Civil Eng. 5(4):515-532.nBažant, Z. P. 1985. Constitutive equation of wood at variable humidity and temperature. Wood Sci. Technol. 19:159-177.nCorotis, R. B., and D. P. Sheehan. 1986. Wood damage accumulation by stochastic load models. ASCE J. Struct. Eng. 112(11):2402-2415.nEllingwood, B., and D. Rosowsky. 1991. Duration of load effects in LRFD for wood construction. ASCE J. Struct. Eng. 117(2):584-599.nEllingwood, B., T. V. Galambos, J. G. MacGregor, and C. A. Cornell. 1980. Development of a probability based load criterion for American National Standard A58. National Bureau of Standards Special Publication SP No. 577. Washington, DC.nFoschi, R. O., and J. D. Barrett. 1982. Load duration effects in western hemlock lumber. ASCE J. Struct. Div. 108(7):1494-1510.nFoschi, R. O., and Z. C. Yao. 1986. Another look at three duration of load models. Report by Working Commission W18—Timber Structures, International Council for Building Research Studies and Documentation. Florence, Italy.nFoschi, R. O., B. R. Folz, and F. Z. Yao. 1989. Reliability-based design of wood structures. Structural Research Series Report No. 34. Department of Civil Engineering, University of British Columbia, Vancouver, Canada.nFridley, K. J., R. C. Tang, and L. A. Soltis. 1991. Load-duration effects in structural lumber: A strain energy approach. Submitted to ASCE J. Struct. Eng.nFridley, K. J., R. C. Tang, and L. A. Soltis. 1992a. Hygrothermal effects on the mechanical properties of lumber. ASCE J. Struct. Eng. 118(2) (in press).nFridley, K. J., R. C. Tang, and L. A. Soltis. 1992b. Hygrothermal effects on load-duration behavior of structural lumber. ASCE J. Struct. Eng. 118(4) (in press).nGerhards, C. C. 1979. Time-related effects of loading on wood strength. A linear cumulative damage theory. Wood Sci. 11(3):139-144.nGerhards, C. C., 1988. Effect of grade on load duration of Douglas-fir in bending. Wood Fiber Sci. 20(1):146-161.nGerhards, C. C., and C. L. Link. 1986. Effect of loading rate on bending strength of Douglas-fir 2 by 4's. Forest Prod. J. 36(2):63-66.nHendrickson, E. M., B. Ellingwood, and J. Murphy. 1987. Limit state probabilities for wood structural members. ASCE J. Struct. Eng. 113(1):88-106.nJohns, K., and B. Madsen. 1982. Duration of load effects in lumber. Part I. A fracture mechanics approach. Canadian J. Civil Eng. 9(4):502-514.nKaracabeyli, E. 1987. Duration of load research for lumber in North America. Report prepared for the Canadian Wood Council Lumber Properties Steering Committee. Forintek Canada Corp., Canada.nLarrabee, R. D., and C. A. Cornell. 1981. Combination of various load processes. ASCE J. Struct. Div. 107(1):223-239.nMadsen, B. 1973. Duration of load tests for dry lumber in bending. Forest Prod. J. 23(2):21-28.nMadsen, B. 1975. Strength values for wood and limit states design. Canadian J. Civil Eng. 2(3):270-279.nMartin, J. W. 1980. The analysis of life data for wood in the bending mode. Wood Sci. Technol. 14:187-206.nMelchers, R. E. 1987. Structural reliability: Analysis and prediction. Ellis Horwood Ltd., distributed by John Wiley and Sons, New York, NY.nMiner, M. A. 1945. Cumulative damage in fatigue. ASME J. Appl. Mech. 67:A159-A164.nNational Forest Products Association. 1986. National design specification for wood construction. NFPA, Washington, DC.nNielsen, L. F. 1986a. Wood as a cracked viscoelastic material. Part I. Theory and application. Proceedings of the International Workshop on Duration of Load in Lumber and Wood Products. SP-27. Forintek Canada Corp., Canada.nNielsen, L. F. 1986b. Wood as a cracked viscoelastic material. Part II. Sensitivity of justification. Proceedings of the International Workshop on Duration of Load in Lumber and Wood Products. SP-27. Forintek Canada Corp., Canada.nNielsen, L. F., and K. Kousholt. 1980. Stress-strength-life-time relationship for wood. Wood Sci. 12(3):162-174.nRosowsky, D. V., and B. R. Ellingwood. 1990. Stochastic damage accumulation and probabilistic codified design for wood. Cvil Eng. Rept. No. 1990-02-02. The Johns Hopkins University, Baltimore, MD.nSaunders, S. C., and J. W. Martin. 1988. The problem of strength and duration of load for structural timbers. Proceedings of the 1988 International Timber Engineering Conference. Forest Products Research Society, vol. 1, Madison, WI.nvan der Put, T. A. C. M. 1989a. Theoretical explanation of the mechanosorptive effect in wood. Wood Fiber Sci. 21(3):219-230.nvan der Put, T. A. C. M. 1989b. Deformation and damage processes in wood. Delft University Press, Delft, The Netherlands.nWood, L. W. 1951. Relation of strength of wood to duration of loads. Rept. No. 1916. U.S. Forest Products Laboratory, Madison, WI.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.
