Behavior Of Nailed Connections At Elevated Temperatures
Keywords:
Nails, fire, high temperature, lateral resistance, strength, slip modulus, failure mode, yield theoryAbstract
The lateral resistance of plywood-to-wood nailed joints with interlayer gaps was measured at four temperatures of ambient (30°C). 120°C, 200°C, and 265°C in an exploratory test program. As temperature increased from ambient, strength decreased by 13%, 15%, and 26%, respectively, and slip modulus decreased by 47%, 61%, and 54%, respectively. The largest incremental percent decreases in strength and slip modulus occurred at the lowest temperature increment, between ambient and 120°C, Slip modulus was more negatively affected by temperature than strength. Failure mode IV (two-point nail yield) occurred on nailed joints tested at ambient. 120°C. and 200°C, but shifted to failure mode Ills (one-point nail yield in main member) at 265°C. The shift in failure mode occurred because nonuniform temperatures throughout the joint differentially changed the embedding strength of the wood members. The yield theory predicted failure mode IV for nailed joints tested at ambient, but overestimated the strength of the joint by 40%. The results of this research support recent findings reported by Noren (1996).References
American Society For Testing and Materials. Astm E-119-95a. 1997a. Standard Test Methods for Fire Tests of Building Construction and Materials. Annual Book of ASTM Standards. Vol. 04.07:441-461. Philadelphia, PA.nAmerican Society For Testing and Materials. ASTM D1761-88. 1997b. Standard Test Methods for Mechanical Fasteners in Wood. Annual Book of ASTM Standards. Vol. 04.10:269-280. Philadelphia, PA.nAmerican Society For Testing and Materials. ASTM D 4442-84. 1997c. Standard Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials. Annual Book of ASTM Standards. Vol. 04.10:487-491. Philadelphia, PA.nAune, P., and M. Patton-mallory. 1986a. Lateral load-bearing capacity of nailed joints based on the yield theory: Theoretical development. Research Paper FPL 469. USDA, Forest Serv. Forest Prod. Lab., Madison, WI.nAune, P. 1986b. Lateral load-bearing capacity of nailed joints based on the yield theory: Experimental verification. Research Paper FPL 470. USDA, Forest Serv. Forest Prod. Lab., Madison, WI.nFoschi, R. O. 1974. Load-slip characteristics of nails. Wood Science 7(1):69-76.nFoschi, R. O. 1977. Analysis of wood diaphragms and trusses. Part II: Truss-plate connections. Can. J. Civil Engi. 4: 353-362.nFoschi, R. O. and T. Bonac. 1977. Load-slip characteristics for connections with common nails. Wood Science 9(3): 118-123.nFuller, J. J. 1990. Predicting the thermo-mechanical behavior of a gypsum-to-wood nailed connection. M.S. thesis, Oregon State University, Corvallis, OR.nFuller, J. J., R. J. Leichte, and R. H. White. 1992. Temperature distribution in a nailed gypsum-stud joint exposed to fire. Fire Mater. 16:95-99.nGerhards, C. C. 1982. Effect of moisture content and temperature on the mechanical properties of wood: An analysis of immediate effects. Wood Fiber Sci. 14(1): 4-36.nKnudsen, R. M., and A. P. Schniewind. 1975. Performance of structural wood members exposed to fire. Forest Prod. J. 25(2):23-32.nKuenzi. E. W. 1955. Theoretical design of a nailed or bolted joint under lateral load. Rep. No. D1951. USDA, Forest Serv., Forest Prod. Lab., Madison, WI.nLarsen, H. J. 1977. K. W. Johansen's nail tests. Byg-ningsstatiske Meddelelser. Vol. 48, No. 1. Aalborg, Denmark.nLau. P. W. C., and P. George. 1987. Development of a load-slip test apparatus for nailed joints. Forest Prod. J. 37(11/12):39-44.nLiu, J. Y., and L. A. Solus. 1984. Lateral resistance of nailed joints—A test method. Forest Prod. J. 34(1): 55-60.nLoferski, J. R., and T. E. McLain. 1990. Static and impact flexural properties of common wire nails. Draft submitted to Journal of Testing and Evaluation.nNoren, J. 1996. Load-bearing capacity of nailed joints exposed to fire. Fire Mater. 20:133-143.nNational Design Specification® for Wood Construction. 1997. Edition. American Forest and Paper Association, 164-165.nPellicane, P. J. 1991. Application of the European yield model to nailed joints in southern hardwoods. J. Testing Eval. 19(5):385-393.nPellicane, P. J. 1993. Plywood-solid wood nailed joints under lateral loading. J. Mater. Civil Engi. 5(2):226-236.nPellicane, P. J., J. L. Stone, and M. D. Vanderbilt. 1991. Generalized model for lateral load slip of nailed joints. J. Mater. Civil Engi. 3(1):60-77.nPeyer, S. M. 1995. Lateral resistance of a plywood-to-wood nailed connection at elevated temperatures. M.S. thesis., Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, WI.nSa Ribeiro. R. A., and P. J. Pellicane. 1992. Modeling load-slip behavior of nailed joints. J. Mater. Civil Engi. 4(4):385-398.nShrestha, D., S. Cramer, and R. White. 1995. Simplified models for the properties of dimension lumber and metal-plate connections at elevated temperatures. Forest Prod. J. 45(7/8):35-42.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.
