Timber Beams Strengthened with GFRP Bars: Development and Applications
Publication: Journal of Composites for Construction
Volume 6, Issue 1
Abstract
Repair and rehabilitation of infrastructure is becoming increasingly important for bridges due to material deterioration and limited capacity to accommodate current load levels. An experimental program was undertaken to study the flexural behavior of creosote-treated sawn Douglas fir timber beams strengthened with glass fiber-reinforced polymer (GFRP) bars. Twenty-two half-scale and four full-scale timber beams strengthened with GFRP were tested to failure. The percent reinforcement ratios were between 0.27 and 0.82%. Additional unreinforced timber beams were tested as control specimens. The results have shown that using the proposed experimental technique changed the failure mode from brittle tension to compression failure, and flexural strength increased by 18 to 46%. Research findings indicate the use of near-surface GFRP bars overcomes the effect of local defects in the timber and enhances the bending strength of the members. Based on the experimental results, an analytical model is proposed to predict the flexural capacity of both unreinforced and GFRP-reinforced timber beams. The article also reviews implementation of the proposed technique for strengthening a timber bridge near Winnipeg, Manitoba, Canada.
Get full access to this article
View all available purchase options and get full access to this article.
References
AASHTO. (1996). Standard specifications for highway bridges. Washington, D.C.
ASTM. (1992). “Standard methods for static tests of timber in structural sizes.” ASTM D198-92, Philadelphia, Pa.
Bakoss, S. L., Greenland, A., and Crews, K. I. (1999). “Bridge deck and industrial heavy-duty flooring system based on laminated veneer lumber beams reinforced with carbon fiber composites.” Proc., 8th Int. Conf. on Struct. Faults and Repair, London.
Barrett, J. D., and Lau, W. (1994). Canadian lumber properties, E. D. Jones, ed., Canadian Wood Council, Ottawa.
Bazan, I. M. M. (1980). “Ultimate bending strength of timber beams.”PhD thesis, Nova Scotia Technical College, Halifax, Nova Scotia, Canada.
Bohannan, B.(1962). “Prestressed wood members.” Forest Products J., 12(12), 596–602.
Bohannan, B. (1996). “Effect of member size on bending strength of wood members.” Forest Serv. Res. Paper FPL 56, U.S. Department of Agriculture, Washington, D.C.
Buchanan, A. H.(1990). “Bending strength of lumber.” J. Struct. Eng, 116(5), 1213–1229.
Bulleit, W. M., Sandberg, L. B., and Woods, G. J.(1989). “Steel-reinforced glued laminated timber.” J. Struct. Eng., 115(2), 433–444.
Chajes, M. J., Kaliakin, V. N., and Meyer, A. J. (1996). “Behavior of engineered wood-CFRP beams.” Proc., 5th Int. Conf. on Comp. in Infrastr., H. Saadatmanesh and M. R. Ehsani, eds., Univ. of Arizona, Tucson, Ariz., 870–877.
Davalos, J. F., Qiao, P. Z., and Trimbles, B. S.(2000a). “Fiber-reinforced composite and wood bonded interface. Part 1: Durability and shear strength,” ASTM J. Comp. Technol. Res., 22(4), 224–231.
Davalos, J. F., Qiao, P. Z., and Trimbles, B. S.(2000b). “Fiber-reinforced composite and wood bonded interface. Part 2: Fracture,” ASTM J. Comp. Technol. Res., 22(4), 232–240.
Dorey, A. B., and Cheng, J. J. R. (1996). “The behavior of GFRP glued laminated timber beams.” Proc., Adv. Comp. Mat. in Bridges and Struct. II, M. M. El-Badry, ed., The Canadian Society for Civil Engineering, Montreal, Canada, 787–794.
Hernandez, R., Davalos, J. F., Sonti, S. S., Kim, Y., and Moody, R. C. (1997). “Strength and stiffness of reinforced yellow-poplar glued laminated beams.” Res. Pap. FPL-RP-554, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wisc.
Johns, K. C., and Lacroix, S. (2000). “Composite reinforcement of timber in bending.” Can. J. of Civil Engrg., 27, 899–906.
Lantos, G.(1970). “The flexural behavior of steel reinforced laminated timber beams.” Wood Sci., 2(3), 136–143.
Madsen, B., and Buchanan, A. H.(1986). “Size effects in timber explained by a modified weakest link theory.” Can. J. Civ. Eng., Ohawa, 13(2), 218–232.
Mark, R.(1961). “Wood-aluminum beams within and beyond the elastic range.” Forest Products J., 11(10), 477–484.
Peterson, J.(1965). “Wood beams prestressed with bonded tension elements.” J. Struct. Eng., 91(1), 103–119.
Plevris, N., and Triantafillou, T. C.(1992). “FRP-reinforced wood as a structural material.” J. Mater. Civ. Eng., 4(3), 300–317.
Sliker, A.(1962). “Reinforced wood laminated beams.” Forest Products J., 12(1), 91–96.
Sonti, S. S., GangaRao, H. V. S., and Superfesky, M. C. (1996). “Rehabilitation and strengthening of glulam stringers for bridge superstructures.” Proc., 5th Int. Conf. on Comp. in Infrastr., H. Saadatmanesh and M. R. Ehsani, eds., University of Arizona, Tucson, Ariz., 800–813.
Triantafillou, T. C., and and Deskovic, N. (1992) “Prestressed FRP sheets as external reinforcement of wood members.” J. Struct. Eng., 118(5), 1270–1284.
Weibull, W. (1939). “A statistical theory of the strength of materials.” Proc. No. 151, Royal Swedish Institute of Engineering Research, Stockholm.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 6 • Issue 1 • February 2002
Pages: 11 - 20
Copyright
Copyright © 2002 American Society of Civil Engineers.
History
Received: Feb 3, 2000
Accepted: Apr 14, 2001
Published online: Feb 1, 2002
Published in print: Feb 2002
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.