Title:
Shear Strengthening of Hollow Core Slab Webs using FRP Composite Sheets
Author(s):
Yuanli Wu, Amr El Ragaby and Shaohong Cheng
Publication:
Symposium Paper
Volume:
322
Issue:
Appears on pages(s):
3.1-3.18
Keywords:
Shear capacity, hollow core slab, web, and FRP.
DOI:
10.14359/51706954
Date:
6/18/2018
Abstract:
Precast, prestressed hollow core (PHC) slabs are among the most common concrete deck system in the world. However, due to the manufacturing constraints and the difficulty in providing internal shear reinforcement, the shear capacity of PHC slabs sometimes dictates the design and reduces the efficiency and economics of PHC slabs. The objective of this research project is to develop an innovative application of externally bonded Fiber-Reinforced Polymers (FRP) sheets by installing the sheets along the internal perimeter of the slab voids to strengthen the webshear capacity of PHC slabs. To explore the feasibility and to optimize the new technique, experimental testing was carried out on eight full-scale single web, I shape, specimens (each of 4575 mm “180 in” long, 300 mm “12 in” thick and a 284 mm “11.2 in” wide) that were cut longitudinally out of the PHC slab. Carbon FRP sheets were bonded along the full perimeter on each side of the web specimens. The test specimens were loaded monotonically until
failure under single concentrated load at a shear span/depth ratio of 2.5. The investigated parameters were the width
of the FRP strengthened zone (300 “12 in.”, 450 “18 in.”, and 600 mm “24 in.”) and the number of strengthening layers (2 and 4 layers). The test results showed the efficiency of the proposed technique to enhance the shear strength of PHC slabs.
Related References:
1. A. R. Anderson. (1976). Shear Strength of Prestressed Concrete Beams. Technical Bulletin 76-B11/B12, Concrete Technology Associates, Tacoma, WA, Nov, 45 p.
2. K. D. Palmer and A. E. Schultz. (2010). Factors Affecting Web-Shear Capacity of Deep Hollow core Unit. PCI Journal, Vol. 55, No. 2, pp. 123-146.
3. N. M. Hawkins and S. K. Ghosh. (2006). Shear Strength of Hollow core Slabs. PCI Journal, Vol. 51, No. 1, pp. 110-114.
4. Cheng, S. and Wang, X. (2010). Impact of Interaction between adjacent webs on the shear strength of prestressed concrete hollow-core units. PCI Journal, summer 2010, pp. 46-63.
5. Celal, M. S. (2011). Shear Behaviour of Precast/Prestressed Hollow core Slabs. A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba. The University of Manitoba.
6. Yang, L. (1994). Design of Prestressed Hollow Core Slabs with Reference to Web Shear Failure. Journal of Structural Engineering, ASCE, V. 120, No. 9, pp. 2675-2696.
7. ACI Committee 318. (2011). Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R-11). American Concrete Institute, Farmington Hills, Michigan.
8. Berset J. D. (1992) Strengthening of reinforced concrete beams for shear using FRP composites. Department of civil and environmental engineering, Massachusetts Institute of Technology.
9. Chajes. M. J, Januszka. T. F, Nertz. D. R, Thomason. Jr. T. A. and Jr. W. W. (1995). Shear Strengthening of Reinforced Concrete Beams Using Externally Applied Composite Fibers. ACI Structural Journal, Vol. 92, pp295-303.
10. T. C. Triantafillou. (1998). Shear Strengthening of Reinforced Concrete Beams Using Epoxy-Bonded FRP Composites. ACI Structural Journal, Vol. 95pp: 107-115.
11. M.C. Sundarraja and S. Rajamohan. (2008). Shear Strengthening of RC Beams Using GFRP Vertical Strips –An Experimental Study. Journal of Reinforced Plastics and Composites, Vol. 27, No. 14, pp. 1477–1495.
12. M.C. Sundarraja and S. Rajamohan. (2009). Strengthening of RC beams in shear using GFRP inclined strips – An experimental study. Construction and Building Materials 23. pp. 856–864.
13. A.K. Panigrahi, K.C. Biswal, M.R. Barik. (2014). Strengthening of shear deficient RC T-beams with externally bonded GFRP sheets. Construction and Building Materials 57, pp. 81–91.
14. Deutsche Norm. (2008). Precast Concrete Products–Hollow Core Slabs (includes Amendment A1:2008). DIN EN 1168-08, CEN-European Committee for Standardization, Brussels, Belgium.
15. Canadian Standard Association (CSA). (2004). Design of Concrete Structures, CAN/CSA-A23.3-04. Canadian Standards Association, Rexdale, ON, Canada.
16. SIKA CANADA, Structural engineering solution and products, http://can.sika.com/en/solutions_products/document_download/Structural_Strengthening.html?orderBy=size&orderDir=asc
17. ASTM D3039/D3039M (2014). Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials. ASTM Committee D30 on Composite Materials.