Title:
Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part I: Experimental Study
Author(s):
Osman Kaya, Cem Yalçın, Azadeh Parvin, and Selçuk Altay
Publication:
Structural Journal
Volume:
116
Issue:
1
Appears on pages(s):
17-29
Keywords:
beam-column joints; carbon fiber-reinforced polymers (CFRPs); lap splice; plain reinforcements; reinforced concrete; shear strengthening
DOI:
10.14359/51706922
Date:
1/1/2019
Abstract:
Many of the existing reinforced concrete (RC) structures in Turkey built prior to 1999 have deficient design details due to their non-seismic design or construction flaws. In particular, the beam-column joints (BCJs) experience high shear forces during such events, mainly due to inadequate design detailing of transverse reinforcements as well as inadequate lap splicing. Severe damage or total collapse of structures often occurred. To enhance the performance of such deficient joint systems, several strengthening techniques such as reinforced concrete and steel jacketing, as well as fiber-reinforced polymer (FRP) wrapping, have been proposed. In this study, new shear strengthening techniques were developed using carbon fiber-reinforced polymer (CFRP) to retrofit these insufficient BCJs. The effectiveness of various CFRP wrapping methodologies was investigated experimentally. One control specimen was constructed according to provisions specified by the 1975 Turkish Building Design Code, whereas four other specimens were constructed with deficiencies observed in the practice. Moreover, three additional specimens were constructed to develop alternative shear strengthening techniques via CFRP wrapping. The quasi-static tests were carried out by applying constant axial load and reversed-cyclic lateral load at the top of the column. Comparative analysis of control and CFRP-strengthened specimens’ results showed that significant improvements in the lateral load and the energy dissipation capacities were achieved by using the proposed CFRP-strengthening techniques.
Related References:
1. Beres, A.; White, R. N.; and Gergely, P., “Seismic Performance of Interior and Exterior Beam-to-Column Joints Related to Lightly Reinforced Concrete Frame Buildings: Detailed Experimental Results,” Report No. 92-7, Cornell University, Ithaca, NY, Nov. 1992, 210 pp.
2. Bedirhanoglu, I.; Ilki, A.; Pujol, S.; and Kumbasar, N., “Seismic Behavior of Joints Built with Plain Bars and Low-Strength Concrete,” ACI Structural Journal, V. 107, No. 3, May-June 2010, pp. 300-310.
3. Alcocer, S., and Jirsa, J. O., “Strength of Reinforced Concrete Frame Connections Rehabilitated by Jacketing,” ACI Structural Journal, V. 90, No. 3, May-June 1993, pp. 249-261.
4. Ghobarah, A.; Aziz, T. S.; and Biddah, A., “Rehabilitation of Reinforced Concrete Frame Connections Using Corrugated Steel Jacketing,” ACI Structural Journal, V. 94, No. 3, May-June 1997, pp. 282-294.
5. Geng, Z.; Chajes, M. J.; Chou, T.; and Pan, D. Y., “The Retrofitting of Reinforced Concrete Column-to-Beam Connections,” Composites Science and Technology, V. 58, No. 8, 1998, pp. 1297-1305. doi: 10.1016/S0266-3538(98)00014-1
6. Gergely, J.; Pantelides, C. P.; and Reaveley, L. D., “Shear Strengthening of RCT-Joints Using CFRP Composites,” Journal of Composites for Construction, ASCE, V. 4, No. 2, 2000, pp. 56-64. doi: 10.1061/(ASCE)1090-0268(2000)4:2(56)
7. Granata, P. J., and Parvin, A., “An Experimental Study on Kevlar Strengthening of Beam-Column Connections,” Composite Structures, V. 53, No. 2, 2001, pp. 163-171. doi: 10.1016/S0263-8223(00)00187-2
8. 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
9. 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)
10. Prota, A., Nanni, A., Manfredi G., and Cosenaza, E., “Seismic Upgrade of Beam-Column Joints with FRP Reinforcement,” Industria Italiana del Cemento, Nov. 2000.
11. Parvin, A., and Wu, S., “Evaluation of Wrap Thickness in CFRP-Strengthened Concrete T-Joints,” Proceedings of the Second International Conference on FRP Composites in Civil Engineering, CICE 2004, Adelaide, Australia, Dec. 2004, pp. 643-647.
12. 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
13. Ilki, A.; Bedirhanoglu, I.; and Kumbasar, N., “Behavior of FRP-Retrofitted Joints Built with Plain Bars and Low-Strength Concrete,” Journal of Composites for Construction, ASCE, V. 15, No. 3, 2011, pp. 312-326. doi: 10.1061/(ASCE)CC.1943-5614.0000156
14. 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
15. Gökgöz, E., “Experimental Research on Seismic Retrofitting of R/C Exterior Beam-Column-Slab Joints Upgraded with Carbon Fiber Reinforced Polymer (CFRP) Sheets,” MSc thesis, Boğaziçi University, Istanbul, Turkey, 2008, 140 pp.
16. Topçu, İ., “Experimental Research on Seismic Retrofitting of R/C Corner Beam-Column-Slab Joints Upgraded with Carbon Fiber Reinforced Polymer (CFRP) Sheets,” MSc thesis, Boğaziçi University, Istanbul, Turkey, 2008, 127 pp.
17. “Specification for Structures to be Built in Disaster Areas (TEC-75),” Ministry of Development and Housing, Earthquake Research Institutions, Ankara, Turkey, July 1975, 63 pp.
18. ASTM C39-96, “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,” ASTM International, West Conshohocken, PA, 1996, 5 pp.
19. ASTM A706/A706M-06a, “Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement,” ASTM International, West Conshohocken, PA, 2006, 6 pp.
20. ACI Innovation Task Group 1, “Acceptance Criteria for Moment Frames Based on Structural Testing (ACI ITG 1.1-01),” American Concrete Institute, Farmington Hills, MI, 2001, 10 pp.