Title:
Flexural Strengthening of Reinforced Concrete Beam- Column Joints Using Innovative Anchorage System
Author(s):
Davood Mostofinejad and Alireza Akhlaghi
Publication:
Structural Journal
Volume:
114
Issue:
6
Appears on pages(s):
1603-1614
Keywords:
anchor fan; beam-column joints; debonding; EBROG; fiberreinforced polymer composites; flexure; grooving method; reinforced concrete; seismic rehabilitation; strength
DOI:
10.14359/51700953
Date:
11/1/2017
Abstract:
Application of fiber-reinforced polymer (FRP) composites to enhance the flexural strength of members in the expected plastic hinge regions of ductile reinforced concrete (RC) moment frames for resisting seismic loads are stipulated in the current construction codes and guidelines. The main issues of concern in these documents include provisions for appropriate anchorage details for FRP composites at the beam-column interface, debonding of FRP composites off the concrete substrate, and the effect of cyclic load reversal on FRP reinforcement. The present experimental study was conducted to gain insight into the effectiveness of an innovative FRP anchor fan at the beam-column joint interface flexurally strengthened with carbon FRP (CFRP) sheets. To avoid any likely debonding of FRP composites off the concrete substrate, surface preparation of the test specimens was performed according to a recently developed grooving method (GM) in the form of externally bonded reinforcement on grooves (EBROG). For the purposes of this study, seven half-scale RC beam-column
subassemblies, including a control specimen and six rehabilitated ones, were tested under constant axial and reversal cyclic lateral loadings. The primary test variables were the FRP sheet length along the beam and fiber volume in the CFRP anchor fan. The results indicated that the adopted rehabilitation strategy enhanced the lateral strength of RC joints up to 80% compared to the control one. It was also found that deformation-controlled classification action could be justified for strengthened specimens under specific circumstances.
Related References:
1. Ghobarah, A., and Said, A., “Seismic Rehabilitation of Beam-Column Joints Using FRP Laminates,” Journal of Earthquake Engineering, V. 5, No. 1, 2001, pp. 113-129. doi: 10.1080/13632460109350388
2. Ghobarah, A., and Said, A., “Shear Strengthening of Beam-Column Joints,” Engineering Structures, V. 24, No. 7, 2002, pp. 881-888. doi: 10.1016/S0141-0296(02)00026-3
3. El-Amoury, T., and Ghobarah, A., “Seismic Rehabilitation of Beam-Column Joint Using GFRP Sheets,” Engineering Structures, V. 24, No. 11, 2002, pp. 1397-1407. doi: 10.1016/S0141-0296(02)00081-0
4. Antonopoulos, C. P., and Triantafillou, T. C., “Experimental Investigation of FRP-Strengthened RC Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 7, No. 1, 2003, pp. 39-49. doi: 10.1061/(ASCE)1090-0268(2003)7:1(39)
5. Ghobarah, A., and El-Amoury, T., “Seismic Rehabilitation of Deficient Exterior Concrete Frame Joints,” Journal of Composites for Construction, ASCE, V. 9, No. 5, 2005, pp. 408-416. doi: 10.1061/(ASCE)1090-0268(2005)9:5(408)
6. Mukherjee, A., and Joshi, M., “FRPC Reinforced Concrete Beam-Column Joints under Cyclic Excitation,” Composite Structures, V. 70, No. 2, 2005, pp. 185-199. doi: 10.1016/j.compstruct.2004.08.022
7. Al-Salloum, Y. A., and Almusallam, T. H., “Seismic Response of Interior RC Beam-Column Joints Upgraded with FRP Sheets. I: Experimental Study,” Journal of Composites for Construction, ASCE, V. 11, No. 6, 2007, pp. 575-589. doi: 10.1061/(ASCE)1090-0268(2007)11:6(575)
8. Alsayed, S. H.; Al-Salloum, Y. A.; Almusallam, T. H.; and Siddiqui, N. A., “Seismic Response of FRP-Upgraded Exterior RC Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 14, No. 2, 2010, pp. 195-208. doi: 10.1061/(ASCE)CC.1943-5614.0000067
9. Al-Salloum, Y. A.; Almusallam, T. H.; Alsayed, S. H.; and Siddiqui, N. A., “Seismic Behavior of As-Built, ACI-Complying, and CFRP-Repaired Exterior RC Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 15, No. 4, 2011, pp. 522-534. doi: 10.1061/(ASCE)CC.1943-5614.0000186
10. Pampanin, S.; Bolognini, D.; and Pavese, A., “Performance-Based Seismic Retrofit Strategy for Existing Reinforced Concrete Frame Systems Using Fiber-Reinforced Polymer Composites,” Journal of Composites for Construction, ASCE, V. 11, No. 2, 2007, pp. 211-226. doi: 10.1061/(ASCE)1090-0268(2007)11:2(211)
11. Pantelides, C. P.; Okahashi, Y.; and Reaveley, L., “Seismic Rehabilitation of Reinforced Concrete Frame Interior Beam-Column Joints with FRP Composites,” Journal of Composites for Construction, ASCE, V. 12, No. 4, 2008, pp. 435-445. doi: 10.1061/(ASCE)1090-0268(2008)12:4(435)
12. Karayannis, C. G., and Sirkelis, G. M., “Strengthening and Rehabilitation of RC Beam-Column Joints Using Carbon-FRP Jacketing and Epoxy Resin Injection,” Earthquake Engineering & Structural Dynamics, V. 37, No. 5, 2008, pp. 769-790. doi: 10.1002/eqe.785
13. Engindeniz, M.; Kahn, L. F.; and Zureick, A.-H., “Performance of an RC Corner Beam-Column Joint Severely Damaged under Bidirectional Loading and Rehabilitated with FRP Composites,” Seismic Strengthening of Concrete Buildings Using FRP Composites, SP-258, T. Alkhrdahi and P. Silva, eds., American Concrete Institute, Farmington Hills, MI, 2008, pp. 19-36.
14. Le-Trung, K.; Lee, K.; Lee, J.; Lee, D. H.; and Woo, S., “Experimental Study of RC Beam-Column Joints Strengthened Using CFRP Composites,” Composites. Part B, Engineering, V. 41, No. 1, 2010, pp. 76-85. doi: 10.1016/j.compositesb.2009.06.005
15. Akguzel, U., and Pampanin, S., “Effects of Variation of Axial Load and Bidirectional Loading on Seismic Performance of GFRP Retrofitted Reinforced Concrete Exterior Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 14, No. 1, 2010, pp. 94-104. doi: 10.1061/(ASCE)1090-0268(2010)14:1(94)
16. Parvin, A.; Altay, S.; Yalcin, C.; and Kaya, O., “CFRP Rehabilitation of Concrete Frame Joints with Inadequate Shear and Anchorage Details,” Journal of Composites for Construction, ASCE, V. 14, No. 1, 2010, pp. 72-82. doi: 10.1061/(ASCE)CC.1943-5614.0000055
17. Lee, W. T.; Chiou, Y. J.; and Shih, M. H., “Reinforced Concrete Beam-Column Joint Strengthened with Carbon Fiber Reinforced Polymer,” Composite Structures, V. 92, No. 1, 2010, pp. 48-60. doi: 10.1016/j.compstruct.2009.06.011
18. Sezen, H., “Repair and Strengthening of Reinforced Concrete Beam-Column Joints with Fiber-Reinforced Polymer Composites,” Journal of Composites for Construction, ASCE, V. 16, No. 5, 2012, pp. 499-506. doi: 10.1061/(ASCE)CC.1943-5614.0000290
19. Ha, G.-J.; Cho, C.-G.; Kang, H.-W.; and Feo, L., “Seismic Improvement of RC Beam–Column Joints Using Hexagonal CFRP Bars Combined with CFRP Sheets,” Composite Structures, V. 95, No. 0, 2013, pp. 464-470. doi: 10.1016/j.compstruct.2012.08.022
20. Del Vecchio, C.; Di Ludovico, M.; Balsamo, A.; Prota, A.; Manfredi, G.; and Dolce, M., “Experimental Investigation of Exterior RC Beam-Column Joints Retrofitted with FRP Systems,” Journal of Composites for Construction, ASCE, V. 18, No. 4, 2014, p. 04014002 doi: 10.1061/(ASCE)CC.1943-5614.0000459
21. Yu, J.; Shang, X.; and Lu, Z., “Efficiency of Externally Bonded L-Shaped FRP Laminates in Strengthening Reinforced-Concrete Interior Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 20, No. 3, 2016. doi: 10.1061/(ASCE)CC.1943-5614.0000622
22. Mostofinejad, D., and Akhlaghi, A., “Experimental Investigation of the Efficacy of EBROG Method in Seismic Rehabilitation of Deficient Reinforced Concrete Beam-Column Joints Using CFRP Sheets,” Journal of Composites for Construction, ASCE, V. 21, No. 4, 2017. doi: 10.1061/(ASCE)CC.1943-5614.0000781
23. Eslami, A., and Ronagh, H., “Experimental Investigation of an Appropriate Anchorage System for Flange-Bonded Carbon Fiber-Reinforced Polymers in Retrofitted RC Beam-Column Joints,” Journal of Composites for Construction, ASCE, V. 18, No. 4, 2014, p. 04013056 doi: 10.1061/(ASCE)CC.1943-5614.0000456
24. ACI Committee 440, “Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-08),” American Concrete Institute, Farmington Hills, MI, 2008, 76 pp.
25. Barros, J.; Ferreira, D.; Fortes, A.; and Dias, S., “Assessing the Effectiveness of Embedding CFRP Laminates in the Near Surface for Structural Strengthening,” Construction and Building Materials, V. 20, No. 7, 2006, pp. 478-491. doi: 10.1016/j.conbuildmat.2005.01.030
26. Bournas, D., and Triantafillou, T. C., “Flexural Strengthening of Reinforced Concrete Columns with Near-Surface-Mounted FRP or Stainless Steel,” ACI Structural Journal, V. 106, No. 4, July-Aug. 2009, pp. 495-505.
27. Ioannis, V.; Kefala, E.; and Triantafillou, T. C., “Innovative Flexural Strengthening of Reinforced Concrete Columns Using Carbon-Fiber Anchors,” ACI Structural Journal, V. 110, No. 1, Jan.-Feb. 2013, pp. 63-70.
28. Kim, I.; Jirsa, J. O.; and Bayrak, O., “Anchorage of Carbon Fiber-Reinforced Polymer on Side Faces of Reinforced Concrete Beams to Provide Continuity,” ACI Structural Journal, V. 110, No. 6, Nov.-Dec. 2013, pp. 1089-1098.
29. Kim, I.; Jirsa, J. O.; and Bayrak, O., “Use of Carbon Fiber-Reinforced Polymer to Provide Continuity in Reinforced Concrete Beams under Dynamic Loading,” ACI Structural Journal, V. 112, No. 3, May-June 2015, pp. 383-395. doi: 10.14359/51687423
30. Mostofinejad, D., and Mahmoudabadi, E., “Grooving as Alternative Method of Surface Preparation to Postpone Debonding of FRP Laminates in Concrete Beams,” Journal of Composites for Construction, ASCE, V. 14, No. 6, 2010, pp. 804-811. doi: 10.1061/(ASCE)CC.1943-5614.0000117
31. Mostofinejad, D., and Hajrasouliha, M., “Effect of Concrete Strength and Groove Dimension on Performance of Grooving Method to Postpone Debonding of FRP Sheets in Strengthened Concrete Beams,” Iranian Journal of Science and Technology, Transaction B: Engineering, V. 37, 2013, pp. 219-232.
32. Mostofinejad, D., and Moghaddas, A., “Bond Efficiency of EBR and EBROG Methods in Different Flexural Failure Mechanisms of FRP Strengthened RC Beams,” Construction and Building Materials, V. 54, No. 0, 2014, pp. 605-614. doi: 10.1016/j.conbuildmat.2014.01.002
33. Mostofinejad, D., and Tabatabaei Kashani, A., “Experimental Study on Effect of EBR and EBROG Methods on Debonding of FRP Sheets Used for Shear Strengthening of RC Beams,” Composites. Part B, Engineering, V. 45, No. 1, 2013, pp. 1704-1713. doi: 10.1016/j.compositesb.2012.09.081
34. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R-11),” American Concrete Institute, Farmington Hills, MI, 2011, 503 pp.
35. Noor, F. A., and Boswell, L. F., Small Scale Modelling of Concrete Structures, Elsevier Applied Science, London, UK, 1992.
36. Sika Group, “Woven Carbon Fiber Fabric for Structural Strengthening,” Baar, Switzerland, 2006.
37. ACI Committee 374, “Acceptance Criteria for Moment Frames Based on Structural Testing (ACI 374.1-05) and Commentary,” American Concrete Institute, Farmington Hills, MI, 2005, 9 pp.
38. Paulay, T., and Priestley, M., Seismic Design of Reinforced Concrete and Masonry Buildings, John Wiley & Sons, Inc., New York, 1992.
39. Park, R., “Evaluation of Ductility of Structures and Structural Assemblages from Laboratory Testing,” Bulletin of the New Zealand National Society for Earthquake Engineering, V. 22, No. 3, 1989, pp. 155-166.
40. Priestley, M., and Park, R., “Strength and Ductility of Concrete Bridge Columns under Seismic Loading,” ACI Structural Journal, V. 84, No. 1, Jan.-Feb. 1987, pp. 61-76.
41. Priestley, M.; Seible, F.; and Calvi, G. M., Seismic Design and Retrofit of Bridges, John Wiley & Sons, Inc., New York, 1996.