Shear Strengthening of Interior Slab–Column Connections Using Carbon Fiber-Reinforced Polymer Sheets
Publication: Journal of Composites for Construction
Volume 7, Issue 2
Abstract
This paper presents the results of an experimental investigation undertaken to evaluate the punching shear capacity of interior slab–column connections, strengthened using flexible carbon fiber-reinforced polymer (CFRP) sheets. Sixteen square slab–column connections with different slab thicknesses (55 and 75 mm) and reinforcement ratios (1 and 1.5%) were tested. Twelve specimens were strengthened using CFRP sheets and the remaining four specimens were kept as controls. Without strengthening, all specimens were designed to experience punching shear failure. The CFRP sheets were bonded to the tension face of the specimens in two perpendicular directions parallel to the internal ordinary steel reinforcement. The test results clearly demonstrate that using CFRP leads to significant improvements in the flexural stiffness, flexural strength, and shear capacity of beam–column connections. Depending on the content of the ordinary reinforcement, thickness of the slab, and area of CFRP sheet, the flexural strength increased between 26 and 73% and the shear capacity increased between 17 and 45%. The measured stress in the CFRP sheets at nominal strength varied between 22 and 69% of the ultimate tensile strength of the fibers. Comparison with available prediction equations showed that the punching shear capacity can be predicted with reasonable accuracy if the contribution of CFRP reinforcement to the increase in flexural strength is accounted for. On the other hand, the code design expressions were conservative in predicting the capacity observed in the tests.
Get full access to this article
View all available purchase options and get full access to this article.
References
American Concrete Institute (ACI) Committee 318. (1999). “Building code requirements for reinforced concrete and ACI-ASCE committee 426. (1974). “The shear strength of reinforced concrete members—slabs,” Proc. ASCE, 100, No. ST8, 1543–1591.
Canadian Standards Association (CSA). (1994). “Design of concrete structures for buildings.” CSA-A23.3-94.
Chen, C. C., and Li, C. Y. (2000). “Experimental study on the punching shear behaviour of RC slabs.” Proc., Int. Workshop on Punching Shear Capacity on RC Slabs, 415–422.
Elstner, R. D., and Hognestad, E.(1956). “Shearing strength of reinforced concrete slabs.” ACI J. Proc., 53(1), 29–58.
Erki, M. A., and Heffernan, P. J. (1995). “Reinforced concrete slabs externally strengthened with fibre reinforced plastics materials.” Proc., 2nd Int. Symp. on Non-Metalic FRP Reinforcement for Concrete Structures, L. Taerwe, ed., 509–516.
Ghali, A., Sargious, M. A., and Huizer, A. (1974). “Vertical prestressing of flat plates around columns.” Shear in Reinforced Concrete, ACI Special Publ. No. SP-42, 2, 905–920.
Ichimasu, H., Maruyama, M., Watanabe, H., and Hirose, T. (1993). “RC slabs strengthened by bonded carbon FRP plates.” Int. Symp. on Fibre Reinforced Polymer Reinforcements for Concrete Structures, ACI Special Publ. No. SP-138, 932–955.
ISIS Canada. (2001). “Strengthening reinforced concrete structures with externally bonded fibre reinforced polymers (FRPs).” Design manual No. 4, K. Neale, ed.
Karbhari, V. M., Seible, F., Seim, W., and Vasques, A. (1996). “Post-strengthening of concrete slabs.” Int. Symp. on Fiber Reinforced Polymer Reinforcements for Concrete Structures, ACI Special Publication No. SP-188, 1163–1173.
Malvar, L. J., Warren, G. E., and Inaba, C. M. (2000). “Large scale tests on Navy reinforced concrete pier decks strengthened with CFRP sheets.” Proc., 3rd Int. Conf. on Advanced Composite Materials in Bridges and Structures, 497–504.
Moe, J. (1961). “Shearing strength of reinforced concrete slabs and footings under concentrated loads.” Bull. No. D47, Research and Development Laboratories, Portland Cement Association, Skokie, Illinois.
Mowrer, R. D., and Vanderbilt, M. D.(1967). “Shear strength of lightweight aggregate reinforced concrete flat plates.” J. Am. Concr. Inst., 64(11), 722–729.
Ramos, A. M., Lucio, V. J., and Regan, P. E. (2000). “Repair and strengthening methods of flat slabs for punching.” Proc., Int. Workshop on Punching Shear Capacity on RC Slabs, 125–133.
Soudki, K. A. (1999). “Rehabilitation of bridges and structures by FRP laminates—Canadian perspective.” ICCRI Workshop.
Tan, K. H. (1996). “Punching shear strength of RC slabs bonded with FRP systems.” Proc., 2nd Int. Conf. on Advanced Composite Materials in Bridges and Structures, 387–394.
Information & Authors
Information
Published In
Copyright
Copyright © 2003 American Society of Civil Engineers.
History
Received: Nov 27, 2001
Accepted: Apr 24, 2002
Published online: Apr 15, 2003
Published in print: May 2003
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.