Calibration of Resistance Factor for Self-Tapping Screws in Canada
Publication: Journal of Structural Engineering
Volume 148, Issue 3
Abstract
Under the load and resistance factor design philosophy used in North America, building codes structures are designed using load and resistance factors calibrated to a target reliability level. Despite this, few attempts have been made to calibrate resistance factors for timber connections. A calibration process was carried out for the withdrawal resistance of axially loaded self-tapping screws using a database of test results from across Canada. Two load cases were considered, reflecting load combinations and statistics drawn from the 2015 National Building Code of Canada and from a proposal developed to provide greater consistency in reliability outcomes, and the reliability under each case was determined using the first-order reliability method (FORM). Given the low ductility–brittle nature of withdrawal failures, a resistance factor of was recommended for a target reliability index of . The outcomes will assist in the selection of a resistance factor for self-tapping screws for use in the Canadian timber design standard, CSA O86.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors kindly thank Western Archrib for donating the timber material and Rotho Blaas for donating the test setup and screws used in the withdrawal tests at the University of Alberta, and to Dr. Alex Salenikovich from the University of Laval and Mr. Shawn Kennedy for providing withdrawal strength data for Kennedy et al. (2014) and Gehloff (2011). Funding for the study was provided by the Natural Science and Engineering Research Council of Canada (NSERC) Industry Research Chair in Engineered Wood & Building Systems.
References
Abukari, M. H. 2012. “The performance of structural screws in Canadian glulam.” Master’s thesis, Dept. of Civil Engineering and Applied Mechanics, McGill Univ.
Asiz, A., and I. Smith. 2005. “New generation of timber design practices and code provisions linking system and connection design.” In Proc., Meeting 38 Int. Council for Building Research Studies and Documentation, CIB-W18—Timber Structures. Karlsruhe, Germany: Timber Structures, Universtität Karlsruhe.
ASTM. 2017. Standard specification for computing reference resistance of wood-based materials and structural connections for load and resistance factor design. ASTM D5457-17. West Conshohocken, PA: ASTM.
Bartlett, F. M., H. P. Hong, and W. Zhou. 2003a. “Load factor calibration for the proposed 2005 edition of the National Building Code of Canada: Companion-action load combinations.” Can. J. Civ. Eng. 30 (2): 440–448. https://doi.org/10.1139/l02-086.
Bartlett, F. M., H. P. Hong, and W. Zhou. 2003b. “Load factor calibration for the proposed 2005 edition of the National Building Code of Canada: Statistics of loads and load effects.” Can. J. Civ. Eng. 30 (2): 429–439. https://doi.org/10.1139/l02-087.
Bulleit, W. M. 2006. “Reliability of steel doweled wood connections designed to ASCE 16-95.” J. Struct. Eng. 132 (3): 441–448. https://doi.org/10.1061/(ASCE)0733-9445(2006)132:3(441).
Casella, G., and R. L. Berger. 2002. Statistical inference. Pacific Grove, CA: Duxbury.
CEN (European Committee for Standardization). 1999. Timber structures—Test methods—Withdrawal capacity of timber fasteners. EN 1382. Brussels, Belgium: CEN.
CEN (European Committee for Standardization). 2014. Design of timber structures—Part 1-1: General—Common rules and rules for buildings. Brussels, Belgium: CEN.
CSA (Canadian Standards Association). 2011. Guidelines for the development of limit states design standards. CSA S408-11. Mississauga, ON, Canada: CSA.
CSA (Canadian Standards Association). 2019a. Design of steel structures. CSA S16-19. Mississauga, ON, Canada: CSA.
CSA (Canadian Standards Association). 2019b. Engineering design in wood. CSA O86-19. Mississauga, ON, Canada: CSA.
Foschi, R. O., B. Folz, and F. Yao. 1992. Reliability-based design of wood structures. Vancouver, Canada: Dept. of Civil Engineering, Univ. of British Columbia.
Gehloff, M. 2011. “Pull-out resistance of self-tapping wood screws with continuous thread.” Master’s thesis, Dept. of Wood Science, Univ. of British Columbia.
Ghosn, M., et al. 2016. “Reliability-based performance indicators for structural members.” J. Struct. Eng. 142 (9): F4016002. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001546.
Hong, H. P., T. G. Mara, R. Morris, S. H. Li, and W. Ye. 2014. “Basis for recommending an update of wind velocity pressures in Canadian design codes.” Can. J. Civ. Eng. 41 (3): 206–221. https://doi.org/10.1139/cjce-2013-0287.
Hong, H. P., Q. Tang, S. C. Yang, and X. Z. Cui. 2020. Reliability-based calibration of ultimate return periods for the design wind load and snow load considering the historical climate statistics and climate change effects. London: Dept. of Civil and Environmental Engineering, Univ. of Western Ontario.
Hong, H. P., and W. Ye. 2014. “Analysis of extreme ground snow loads for Canada using snow depth records.” Nat. Hazards 73 (2): 355–371. https://doi.org/10.1007/s11069-014-1073-z.
Hübner, U. 2013. “Withdrawal strength of self-tapping screws in hardwoods.” In Proc., Meeting 46 Int. Council for Building Research Studies and Documentation, CIB-W18—Timber Structures. Karlsruhe, Germany: Universtität Karlsruhe.
Kennedy, S., A. Salenikovich, W. Munoz, and M. Mohammad. 2014. “Design equation for withdrawal resistance of threaded fasteners in the Canadian timber design code.” In Proc., World Conf. on Timber Engineering. Quebec: Laval Univ.
NRCC (National Research Council of Canada). 2015. National Building Code of Canada. Ottawa, Canada: NRCC.
Pirnbacher, G., R. Brander, and G. Schickhofer. 2009. “Base parameters of self-tapping screws.” In Proc., Meeting 42 Int. Council for Building Research Studies and Documentation, CIB-W18—Timber Structures. Karlsruhe, Germany: Timber Structures, Universtität Karlsruhe.
Ringhofer, A. 2017. “Axially loaded self-tapping screws in solid timber and laminated timber products.” Ph.D. thesis, Institute of Timber Engineering and Wood Technology, Technische Universität Graz.
Ringhofer, A., R. Brandner, and G. Schickhofer. 2015. “Withdrawal resistance of self-tapping screws in unidirectional and orthogonal layered timber products.” Mater. Struct. 48 (5): 1435–1447. https://doi.org/10.1617/s11527-013-0244-9.
Smith, I., A. Asiz, M. Snow, and Y. H. Chui. 2006. “Possible Canadian/ISO approach to deriving design values from test data.” In Proc., Meeting 39 Int. Council for Building Research Studies and Documentation, CIB-W18—Timber Structures. Karlsruhe, Germany: Timber Structures, Universtität Karlsruhe.
Yasumura, M., and N. Kawai. 1997. “Evaluation of wood framed shear walls subjected to lateral load.” In Proc., Meeting 30 Int. Council for Building Research Studies and Documentation, CIB-W18—Timber Structures. Karlsruhe, Germany: Timber Structures, Universtität Karlsruhe.
Zhang, C., Z. Li, G. Lee, and F. Lam. 2013a. Evaluation of bolted connections in Douglas Fir and Western Hemlock. Vancouver, Canada: Univ. of British Columbia.
Zhang, C., H. Yan, G. Lee, Y. Li, and F. Lam. 2013b. Connection design for post and beam construction—Performance of bolted connection in Western Hemlock. Vancouver, Canada: Univ. of British Columbia.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 148 • Issue 3 • March 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Dec 29, 2020
Accepted: Oct 11, 2021
Published online: Jan 7, 2022
Published in print: Mar 1, 2022
Discussion open until: Jun 7, 2022
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.