Load‐Distribution Model for Light‐Frame Wood Roof Assemblies
Publication: Journal of Structural Engineering
Volume 115, Issue 10
Abstract
Design methods for light‐frame roof assemblies assume a weakestlink failure criterion. They provide little recognition of load‐sharing and compositeaction effects on redundant assemblies. A computer model that may be used to determine how loads are distributed in a trussed roof assembly was developed and verified on the basis of four light‐frame roof assembly tests. This model is embodied in a special‐purpose matrix frame analysis program called ROOFSYS. Simplifying assumptions made in this version of the model limit its application to the prediction of load distribution among trusses of varying stiffness, given the stiffness characteristics of individual truss elements. In addition to describing the model, behavior of light‐frame wood roof assemblies is discussed as it relates to model development and observations from the full‐scale assembly tests. If a reliable relationship between truss strength and stiffness can be established, the ROOFSYS model can be used to establish load‐sharing increase factors for light‐frame wood roof assembles.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Criswell, M. E. (1986). “Design of columns.” In Wood: Engineering design concepts, A. D. Freas, R. C. Moody, and L. A. Soltis, eds., Materials Research Council, The Pennsylvania State Univ., University Park, Pa., 293–364.
2.
“Design/construction guide: residential and commercial.” (1986). Form No. E30F/Revised Jan. 1986, American Plywood Association (APA), Tacoma, Wash.
3.
Egerup, A. R. (1975). “Theoretical and experimental determination of the stiffness and ultimate load of timber trusses,” thesis presented to the Technical University of Denmark, in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
4.
Foschi, R. O. (1977). “Analysis of wood diaphragms and trusses, Part II: Truss plate connections.” Can. J. Civ. Engrg., National Research Council of Canada, Ottawa, Ontario, Canada, 4(3), 353–362.
5.
Foschi, R. O. (1979). “Truss plate modeling in the analysis of trusses.” Proc. Metal Plate Wood Truss Conference, Forest Products Research Society, Madison, Wis.
6.
Gromala, D. S., and Wheat, D. L. (1984). “Structural analysis of light frame subassemblies.” In Structural wood research, R. Itani and K. Faherty, eds. Proc., Workshop Sponsored by Committee on Wood of the ASCE Structural Division, the National Science Foundation, and Washington State Univ., Structural Division, Milwaukee, Wis., Oct. 1983, ASCE, New York, N.Y., 73–108.
7.
Jazayery, B., and Wheat, D. L. (1985). “Second‐order effects in light‐frame wood structures.” Report from Dept. of Civ. Engrg., Univ. of Texas at Austin, Austin, Tex.
8.
Kuenzi, E. W., and Wilkinson, T. L. (1971). “Composite beams—Effect of adhesive or fastener rigidity,” Res. Paper FPL 152, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
9.
“Load sharing in roof assemblies utilizing roof trusses with plywood sheathing and spaced board sheathing.” (1975). National Association of Home Builders (NAHB) Research Foundation, Rockville, Md.
10.
Mayo, A. P. (1978). “Trussed rafter roofs—Load distribution and lateral stability.” Build. Res. Estab. Info. Paper, Princes Risborough Lab.
11.
McCarthy, M. and Wolfe, R. (1987). “Assessment of truss plate performance model applied to southern pine truss joints.” Res. Paper FPL 483, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
12.
McCutcheon, W. J. (1984). “Deflections of uniformly loaded floors.” Res. Paper FPL 449, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
13.
National design specification for wood construction. (1986). National Forest Products Association, Washington, D.C.
14.
Nicol‐Smith, C. A. (1977). “Two‐way action of pitched roofs.” Forest Products J., 27(5), 55.
15.
Pierce, C. B. (1982). “Load sharing between rafters in a traditional roof structure.” Build. Res. Estab. Info. Paper, Princes Risborough Lab, Aylesbury, Buckinghamshire, England.
16.
Seif, S., Vanderbily, M. D., and Goodman, J. R. (1981). “Analysis of composite wood trusses,” Struct. res. report number 38, Civ. Engrg. Dept., Colorado State Univ., Fort Collins, Colo.
17.
Steigerwald, J. P. (1986). “Component interaction in wood roof systems,” report, submitted to the Univ. of Wisconsin‐Madison, Dept. of Civ. and Environ. Engrg., in partial fulfillment of the requirements for the degree of Master of Science.
18.
Suddarth, S. K., and Wolfe, R. W. (1984). “Purdue plane structures analyzer II.” General Tech. Rep. FPL‐40, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
19.
Triche, M. H., and Suddarth, S. K. (1988). “Advanced design of metal plate connector joints.” Forest Products J., 38(9), 7–12.
20.
Vanderbilt, M. D. (1974). Matrix structural analysis, Quantum Publishers, New York, N.Y.
21.
Wang, C. K. (1983). Intermediate structural analysis, McGraw‐Hill, Inc., New York, N.Y.
22.
Wolfe, R. W., LaBissoniere, T., and Cramer, S. M. (1988). “Performance tests of light‐frame roof assemblies.” Proc., 1988 International Timber Engineering Conference, Forest Products Research Society, Madison, Wis.
23.
Wolfe, R. W., and McCarthy, M. (1989). “Tests of light frame roof systems/Overplated truss‐rafter,” Res. Paper FPL 492, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
24.
Wolfe, R. W., Percival, D. H., and Moody, R. C. (1986). “Strength and stiffness of light‐frame sloped trusses.” Res. Paper FPL 471, U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis.
25.
Wolfe, R. W., and Varoglu, E. (1986). “Modeling the structural performance of light‐frame roof systems.” Proc., 10th Triennial Congress of the International Council for Building Res., Studies and Documentation, Center for Building Technology, Gaithersburg, Md., Sept.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 115 • Issue 10 • October 1989
Pages: 2603 - 2616
Copyright
Copyright © 1989 ASCE.
History
Published online: Oct 1, 1989
Published in print: Oct 1989
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.