Experimental Investigation and Modeling of Thermal Effects on a Typical Cross-Laminated Timber Bracket Shear Connection
Publication: Journal of Materials in Civil Engineering
Volume 32, Issue 6
Abstract
Connections in mass timber structural systems are critical for transferring lateral forces from mass timber elements such as shear walls and diaphragms. Cross-laminated timber (CLT) is a prominent mass timber material used to manufacture these wall and floor assemblies. Although research exists that investigated the fire performance of CLT walls and floors, very little investigation has been devoted to the thermal performance of the connection systems themselves. This void in the data and knowledge surrounding CLT connections is an impediment for modeling the elevated temperature performance of CLT structures. Therefore, a series of shear tests were conducted on a CLT L-bracket connection assembly to characterize the thermal degradation of peak loads and initial stiffness as a function of exposure duration at a given temperature. A total of 116 specimens, including four control specimens, were tested according to a matrix of 28 exposure duration-temperature combinations. Two analytical models are developed to explain the thermal degradation—one assuming a mechanism based on first-order kinetics and the second using a statistical regression. The results of this work indicate that the degradation of peak load and initial stiffness with respect to exposure duration occurred at a linear rate and depended on temperature, according to the Arrhenius activation energy theory. This research is a step toward a holistic evaluation of elevated temperature modeling of CLT structures.
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 generated or used during the study are available from the corresponding author by request, including raw data, MATLAB scripts for data processing, and processed spreadsheets.
Acknowledgments
The authors extend their acknowledgments to the USDA Agriculture Research Service for providing funding for this research. We would like to acknowledge Dr. Omar Amini and Dr. John van de Lindt from Colorado State University for sharing the specifications for the connection used in this research. We would also like to acknowledge D. R. Johnson Lumber for providing the CLT and executing the CNC work. Lastly, we would like to thank those faculty members, graduate students, and undergraduate workers at Oregon State University who provided input and assistance throughout the experimental testing program.
References
Akgul, T., and A. Sinha. 2016. “Degradation of yield strength of laterally loaded wood-to-oriented strandboard connections after exposure to elevated temperatures.” Wood Fiber Sci. 48 (2): 1–9.
Amini, M. O., J. W. van de Lindt, D. Rammer, S. Pei, P. Line, and M. Popovski. 2018. “Systematic experimental investigation to support the development of seismic performance factors for cross laminated timber shear wall systems.” Eng. Struct. 172 (May): 392–404. https://doi.org/10.1016/j.engstruct.2018.06.021.
APA–The Engineered Wood Association. 2018. Standard for performance-rated cross-laminated timber. ANSI PRG320. Tacoma, WA: APA–The Engineered Wood Association.
ASCE. 2013. Seismic evaluation and retrofit of existing buildings. ASCE 41. Reston, VA: ASCE.
ASCE. 2016. Minimum design loads for buildings and other structures. ASCE 7. Washington, DC: ASCE.
ASTM. 2009. Standard specification for steel sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the hot-dip process. A653. West Conshohocken, PA: ASTM.
ASTM. 2014a. Standard test methods for fire tests of building construction and materials. E119. West Conshohocken, PA: ASTM.
ASTM. 2014b. Standard specification for carbon steel bolts, studs, and threaded rod 60,000 PSI tensile strength. A307. West Conshohocken, PA: ASTM.
AWC (American Wood Council). 2018. National design specification (NDS) for wood construction. Leesburg, VA: AWC.
BCD (Oregon Building Code Division). 2015. Oregon statewide alternate method no. 15-01. Salem, OR: BCD.
Blomgren, H. E., S. Pei, Z. Jin, J. Powers, J. D. Dolan, J. W. van de Lindt, A. R. Barbosa, and D. Huang. 2019. “Full-scale shake table testing of cross-laminated timber rocking shear walls with replaceable components.” J. Struct. Eng. 145 (10): 04019115. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002388.
Durlinger, B., E. Crossin, and J. Wong. 2013. Life cycle assessment of a cross laminated timber building. Melbourne, Australia: Forest and Wood Products.
FEMA. 2009. Quantification of building seismic performance factors. FEMA P-695. Washington, DC: FEMA.
Ganey, R., J. Berman, T. Akbas, S. Loftus, J. D. Dolan, R. Sause, J. Ricles, S. Pei, J. W. van de Lindt, and H. Blomgren. 2017. “Experimental investigation of self-centering cross-laminated timber walls.” J. Struct. Eng. 143 (10): 04017135. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001877.
Gao, M., C. Y. Sun, and C. X. Wang. 2006. “Thermal degradation of wood treated with flame retardants.” J. Therm. Anal. Calorim. 85 (3): 765–769. https://doi.org/10.1007/s10973-005-7225-3.
Gavric, I., M. Fragiacomo, and A. Ceccotti. 2015. “Cyclic behavior of CLT wall systems: Experimental tests and analytical prediction models.” J. Struct. Eng. 141 (11): 04015034. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001246.
Gerhards, C. C. 1982. “Effect of moisture content and temperature on mechanical properties of wood: An analysis of immediate effects.” Wood Fiber Sci. 14 (1): 4–36.
Green, D. W., J. W. Evans, and B. A. Craig. 2003. “Durability of structural lumber products at high temperatures. Part I, 66C at 75% RH and 82C at 30% RH.” Wood Fiber Sci. 35 (4): 499–523.
ICC (International Code Council). 2015. International building code. Country Club Hills: ICC.
Klippel, M., C. Leyder, A. Frangi, and M. Fontana. 2014. “Fire tests on loaded cross-laminated timber wall and floor elements.” Fire Saf. Sci. 11: 626–639. https://doi.org/10.3801/IAFSS.FSS.11-626.
Krawinkler, H., F. Parisi, L. Ibarra, A. Ayoub, and R. Medina. 2001. Development of a testing protocol for woodframe structures. Richmond, CA: CUREE-Caltech Woodframe Project.
Kretschmann, D. E. 2010. “Mechanical properties of wood, general technical report FPL-GTR-190.” Chap. 5 in Wood handbook: Wood as an engineering material. Madison, WI: US Dept. of Agriculture, Forest Service, Forest Products Laboratory.
Lebow, P. K., and J. E. Winandy. 1999. “Verification of the kinetics-based model for long-term effects of fire retardants on bending strength at elevated temperatures.” Wood Fiber Sci. 31 (1): 49–61.
Liu, Y., H. Guo, C. Sun, and W. Chang. 2016. “Assessing cross laminated timber (CLT) as an alternative material for mid-rise residential buildings in cold regions in china-A life-cycle assessment approach.” Sustainability 8 (10): 1047. https://doi.org/10.3390/su8101047.
Mahdavifar, V., A. R. Barbosa, A. Sinha, L. Muszynski, R. Gupta, and S. E. Pryor. 2019. “Hysteretic response of metal connections on hybrid cross-laminated timber panels.” J. Struct. Eng. 145 (1): 04018237. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002222.
Mahdavifar, V., A. Sinha, L. Muszynski, A. R. Barbosa, and R. Gupta. 2018. “Lateral and withdrawal capacity of fasteners on hybrid cross-laminated timber panels.” J. Mater. Civ. Eng. 30 (9): 04018226. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002432.
Muszynski, L., R. Gupta, N. Osborn, and B. Pickett. 2019. “Fire resistance of unprotected cross-laminated timber (CLT) floor assemblies produced in the USA.” Fire Saf. J. 107 (Jul): 126–136.
Osborne, L., C. Dagenais, N. Benichou, and C. Lum. 2012. Preliminary CLT fire resistance testing report. Quebec: FPInnovations.
Pei, S., J. Ricles, D. R. Rammer, J. W. van de Lindt, J. D. Dolan, R. Sause, J. W. Berman, M. Popovski, and H. Blomgren. 2014. “Cross-laminated timber for seismic regions: Progress and challenges for research and implementation.” J. Struct. Eng. 142 (4): E2514001. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001192.
Pei, S., J. W. van de Lindt, A. R. Barbosa, J. Berman, E. McDonnell, J. D. Dolan, H. Blomgren, E. Zimmerman, D. Huang, and S. Wichman. 2019. “Experimental seismic response of a resilient two-story mass timber building with post-tensioned rocking walls.” J. Struct. Eng. 145 (11): 04019120. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002382.
Popovski, M., J. Schneider, and M. Schweinsteiger. 2010. “Lateral load resistance of cross-laminated wood panels.” In Proc., World Conf. on Timber Engineering. London: Wood Technology Society.
Robertson, A. B., F. C. F. Lam, and R. J. Cole. 2012. “A comparative cradle-to-gate life cycle assessment of mid-rise office building construction alternatives: Laminated timber or reinforced concrete.” Buildings 2 (3): 245–270. https://doi.org/10.3390/buildings2030245.
Schaffer, E. L. 1970. “Elevated temperature effect on the longitudinal mechanical properties of wood.” Ph.D. thesis, Dept. of Mechanical Engineering, Univ. Wisconsin.
Shahnewaz, M., S. Alam, and T. Tannert. 2018. “In-plane strength and stiffness of cross-laminated timber shear walls.” Buildings 8 (8): 100. https://doi.org/10.3390/buildings8080100.
Sinha, A., R. Gupta, and J. A. Nairn. 2011a. “Thermal degradation of bending properties of structural wood and wood-based composites.” Holzforschung 65 (2): 221–229. https://doi.org/10.1515/hf.2011.001.
Sinha, A., I. Morrell, and T. Akgul. 2016. “Thermal degradation modeling for single-shear nailed connections.” Wood Mater. Sci. Eng. 13 (1): 16–20. https://doi.org/10.1080/17480272.2016.1226947.
Sinha, A., J. A. Nairn, and R. Gupta. 2011b. “Thermal degradation of bending strength of plywood and oriented strand board: A kinetics approach.” Wood Sci. Technol. 45 (2): 315–330. https://doi.org/10.1007/s00226-010-0329-3.
van de Lindt, J. W., J. Furley, M. O. Amini, S. Pei, G. Tamagnone, A. R. Barbosa, D. Rammer, P. Line, M. Fragiacomo, and M. Popovski. 2019. “Experimental seismic behavior of a two-story CLT platform building.” Eng. Struct. 183 (Mar): 408–422. https://doi.org/10.1016/j.engstruct.2018.12.079.
White, R. H., and M. A. Dietenberger. 2010. “Fire safety of wood construction.” Chap. 18 in Wood handbook: Wood as an engineering material. Madison, WI: US Dept. of Agriculture, Forest Service, Forest Products Laboratory.
Wiesner, F., D. Bell, L. Chaumont, L. Bisby, and S. Deeny. 2018. “Rolling shear capacity of CLT at elevated temperature.” In Proc., World Conf. on Timber Engineering. Seoul: National Institute of Forest Science.
Wiesner, F., L. A. Bisby, A. I. Bartlett, J. P. Hidalgo, S. Santamaria, S. Deeny, and R. M. Hadden. 2019. “Structural capacity in fire of laminated timber elements in compartments with exposed timber surfaces.” Eng. Struct. 179 (Jan): 284–295. https://doi.org/10.1016/j.engstruct.2018.10.084.
Winandy, J. E., and P. K. Lebow. 1996. “Kinetics models for thermal degradation of strength of fire-retardant treated wood.” Wood Fiber Sci. 28 (1): 39–52.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 32 • Issue 6 • June 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: Apr 15, 2019
Accepted: Sep 13, 2019
Published online: Mar 17, 2020
Published in print: Jun 1, 2020
Discussion open until: Aug 17, 2020
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.