Structural Engineering and Mechanics

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Assessment of seismic demand and damping of a reinforced concrete building after CFRP jacketing of columns

  • Inci, Pinar (Department of Civil Engineering, Istanbul Kultur University) ;
  • Goksu, Caglar (Faculty of Civil Engineering, Istanbul Technical University) ;
  • Tore, Erkan (Department of Civil Engineering, Balikesir University) ;
  • Binbir, Ergun (Faculty of Civil Engineering, Istanbul Technical University) ;
  • Ates, Ali Osman (Department of Civil Engineering, Faculty of Technology, Gazi University) ;
  • Ilki, Alper (Faculty of Civil Engineering, Istanbul Technical University)
  • Received : 2021.03.16
  • Accepted : 2022.03.16
  • Published : 2022.06.10
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Abstract

While the lateral confinement provided by an FRP jacket to a concrete column is passive in nature, confinement is activated when the concrete expands due to additional compression stresses or significant shear deformations. This characteristic of FRP jacketing theoretically leads to similar initial stiffness properties of FRP retrofitted buildings as the buildings without retrofit. In the current study, to validate this theoretical assumption, the initial stiffness characteristics, and thus, the potential seismic demands were investigated through forced vibration tests on two identical full-scale substandard reinforced concrete buildings with or without FRP retrofit. Power spectral density functions obtained using the acceleration response data captured through forced vibration tests were used to estimate the modal characteristics of these buildings. The test results clearly showed that the natural frequencies and the mode shapes of the buildings are quite similar. Since the seismic demand is controlled by the fundamental vibration modes, it is confirmed using vibration-based full-scale tests that the seismic demands of RC buildings remain unchanged after CFRP jacketing of columns. Furthermore, the damping characteristics were also found similar for both structures.

Keywords

Acknowledgement

Authors acknowledge DowAksa Advanced Composites Holding B.V. and Governorship of Yalova for various supports provided for experimental studies. The contributions of Ilgaz Dogan (DowAksa), Cem Demir (PhD, ITU), Mustafa Comert (PhD, Rise Eng.), Ali Naki Sanver (MSc, Rise Eng.), Gokhan Sari (Undergrad., Balikesir University), Emin Amini (Undergrad., Balikesir University), Tamer Sahna (Undergrad., Balikesir University), Oguzhan Sozer (Undergrad., Balikesir University), Berkay Aldirmaz (MSc Cand., ITU), Omer Faruk Halici (PhD Candidate, ITU), Mehmet Aksa (Undergrad., Kultur Uni.) are also gratefully acknowledged.

References

  1. Abdessemed, M., Kenai, S., Bali, A. and Kibboua, A. (2011), "Dynamic analysis of a bridge repaired by CFRP: Experimental and numerical modelling", Constr. Build. Mater., 25(3), 1270-1276. https://doi.org/10.1016/j.conbuildmat.2010.09.025.
  2. AFAD, Disaster and Emergency Management Presidency, https://tadas.afad.gov.tr/map.
  3. Altunisik, A.C., Karahasan, O.S., Genc, A.F., Okur, F.Y., Gunaydin, M., Kalkan, E. and Adanur, S. (2018a), "Modal parameter identification of RC frame under undamaged, damaged, repaired and strengthened conditions", Measure., 124, 260-276. https://doi.org/10.1016/j.measurement.2018.04.037.
  4. Altunisik, A.C., Karahasan, O.S., Genc, A.F., Okur, F.Y., Gunaydin, M., Kalkan, E. and Adanur, S. (2018b), "Effect of fiber-reinforced polymer strengthening on dynamic characteristics of reinforced concrete frame using model updating", ACI Struct. J., 115, 1589-1601. https://doi.org/10.14359/51706894
  5. ASCE41-17 (2017), Seismic Evaluation and Retrofit of Existing Buildings, ASCE/SEI 41-17, Reston, VA.
  6. Baghiee, N., Esfahani, M.R. and Moslem, K. (2009), "Studies on damage and FRP strengthening of reinforced concrete beams by vibration monitoring", Eng. Struct., 31(4), 875-893. https://doi.org/10.1016/j.engstruct.2008.12.009.
  7. Bai, Y.L., Dai, J.G., Mohammadi, M., Lin, G. and Mei, S.J. (2019), "Stiffness-based design-oriented compressive stressstrain model for large-rupture-strain (LRS) FRP-confined concrete", Compos. Struct., 223, 110953. https://doi.org/10.1016/j.compstruct.2019.110953.
  8. Barros, J.A.O., Dias, S.J.E. and Lima, J.L.T. (2007), "Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams", Cement Concrete Compos., 29, 203-217. https://doi.org/10.1016/j.cemconcomp.2006.09.001.
  9. Bonfiglioli, B., Pascale, G. and Martinez de Mingo, S. (2004), "Dynamic testing of reinforced concrete beams damaged and repaired with CFRP sheets", J. Mater. Civil Eng., ASCE, 16(5), 400-406. https://doi.org/10.1061/(ASCE)0899-1561(2004)16:5(400).
  10. Bournas, D.A. and Triantafillou, T.C. (2011), "Bar buckling in RC columns confined with composite materials", J. Compos. Constr., 15, 393-403. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000180.
  11. Catbas, F.N., Aktan, A.E., Allemang, R.J. and Brown, D.L. (1998), "A correlation function for spatial locations of scaled mode shapes-(COMEF)", Society for Experimental Mechanics, Inc, 16th International Modal Analysis Conference, 2, 1550-1555.
  12. Catbas, F.N., Grimmelsman, K.A., Ciloglu, S.K., Burgos-Gil, I. and Coll-Borgo, M. (2006), "Static and dynamic testing of a concrete T-beam bridge before and after carbon fiber reinforced polymers (CFRP) retrofit", J. Transp. Res. Board, 1976(1), 76-87. https://doi.org/10.1177/0361198106197600109.
  13. Chopra, A.K. (2001), Dynamics of Structures: Theory and Application to Earthquake Engineering, 3rd Edition, Prentice Hall, Upper Saddle River.
  14. Corradi, M., Borri, A., Castori, G. and Coventry, K (2015), "Experimental analysis of dynamic effects of FRP reinforced masonry vaults", Mater., 8(12), 8059-8071. https://doi.org/10.3390/ma8125445.
  15. Del Zoppo, M., Di Ludovico, M., Balsamo, A. and Prota, A. (2018), "Comparative analysis of existing RC columns jacketed with CFRP or FRCC", Polym., 10(4), 361. https://doi.org/10.3390/polym10040361.
  16. Ewins, D.J. (1984), Modal Testing: Theory and Practice, Vol. 15, Letchworth, Research Studies Press.
  17. Fardis, M.N. and Khalili HH (1982), "FRP-encased concrete as a structural material", Mag. Concrete Res., 34, 191-202. https://doi.org/10.1680/macr.1982.34.121.191.
  18. Fenerci, A., Binici, B., Ezzatfar, P., Canbay, E. and Ozcebe, G. (2016), "The effect of infill walls on the seismic behavior of boundary columns in RC frames", Earthq. Struct., 10(3), 539-562. https://doi.org/10.12989/eas.2016.10.3.539.
  19. Ghatte, H.F., Comert, M., Demir, C. and Ilki, A. (2016), "Evaluation of FRP confinement models for substandard rectangular RC columns based on full-scale reversed cyclic lateral loading tests in strong and weak directions", Polym. (Basel), 8, 1-24. https://doi.org/10.3390/polym8090323.
  20. Ilki, A. and Kumbasar, N. (2002), "Behavior of damaged and undamaged concrete strengthened by carbon fiber composite sheets", Struct. Eng. Mech., 13(1), 75-90. https://doi.org/10.12989/sem.2002.13.1.075.
  21. Ilki, A., Comert, M., Demir, C., Orakcal, K., Ulugtekin, D., Tapan, M. and Kumbasar, N. (2014), "Performance based rapid seismic assessment method (PERA) for reinforced concrete frame buildings", Adv. Struct. Eng., 17(3), 439-459. https://doi.org/10.1260/1369-4332.17.3.439.
  22. Ilki, A., Kumbasar, N. and Koc, V. (2004), "Low strength concrete members externally confined with FRP sheets", Struct. Eng. Mech., 18(2), 167-194. https://doi.org/10.12989/sem.2004.18.2.167.
  23. Ilki, A., Tore, E., Demir, C. and Comert, M. (2018), "Code based performance prediction for a full-scale FRP retrofitted building test", Seismic Hazard Risk Assess., 467-477. https://doi.org/10.1007/978-3-319-74724-8_31.
  24. Inci, P., Goksu, C., Tore, E. and Ilki, A. (2021), "Effects of seismic damage and retrofitting on a full-scale substandard RC building-ambient vibration tests", J. Earthq. Eng., 1-28. https://doi.org/10.1080/13632469.2021.1887009.
  25. Lam, L. and Teng, J.G. (2003), "Design-oriented stress-strain model for FRP-confined concrete", Constr. Build. Mater., 17(6-7), 471-489. https://doi.org/10.1016/S0950-0618(03)00045-X.
  26. Lin, G., Zeng, J.J., Teng, J.G. and Li, L.J. (2020), "Behavior of large-scale FRP-confined rectangular RC columns under eccentric compression", Eng. Struct., 216, 110759. https://doi.org/10.1016/j.engstruct.2020.110759.
  27. Mander, J.B., Priestley, M.J. and Park, R. (1988), "Theoretical stress-strain model for confined concrete", J. Struct. Eng., 114(8), 1804-1826. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1804).
  28. Marthong, C. (2019), "Rehabilitation and strengthening of exterior RC beam column connections using epoxy resin injection and FRP sheet wrapping: Experimental study", Struct. Eng. Mech., 72(6), 723-736. https://doi.org/10.12989/sem.2019.72.6.723.
  29. Michel, C., Karbassi, A. and Lestuzzi, P. (2018), "Evaluation of the seismic retrofitting of an unreinforced masonry building using numerical modeling and ambient vibration measurements", Eng. Struct., 158, 124-135. https://doi.org/10.1016/j.engstruct.2017.12.016.
  30. Oggu, P., Gopikrishna, K. and Nagariya, A. (2021), "Seismic behavior and response reduction factors for concrete moment-resisting frames", Bull. Earthq. Eng., 19, 5643-5663. https://doi.org/10.1007/s10518-021-01184-z.
  31. Ozbakkaloglu, T., Lim, J.C. and Vincent, T. (2013), "FRP-confined concrete in circular sections: Review and assessment of stress-strain models", Eng. Struct., 49, 1068-1088. https://doi.org/10.1016/j.engstruct.2012.06.010.
  32. PEER, Pasific Earthquake Research Center. https://peer.berkeley.edu/.
  33. Qiu, Q. and Lau, D. (2018), "Defect detection in FRP-bonded structural system via phase-based motion magnification technique", Struct. Control Hlth. Monit., 25(12), e2259. https://doi.org/10.1002/stc.2259.
  34. Russo, S. (2013), "On the monitoring of historic Anime Sante church damaged by earthquake in L'Aquila", Struct. Control Hlth. Monit., 20(9), 1226-1239. https://doi.org/10.1002/stc.1531.
  35. Saadatmanesh, H., Ehsani, M.R. and Jin L. (1996). Seismic strengthening of circular bridge pier models with fiber composites", ACI Struct. J., 93, 639-647.
  36. Singh, B., Chidambaram, R.S., Sharma, S. and Kwatra, N. (2017), "Behavior of FRP strengthened RC brick in-filled frames subjected to cyclic loading", Struct. Eng. Mech., 64(5), 557-566. https://doi.org/10.12989/sem.2017.64.5.557.
  37. TEC (1975), Specification for Structures to be Built in Disaster Areas, Turkish Ministry of Public Works and Settlement, Ankara. (in Turkish)
  38. Tore, E., Demir, C., Comert, M. and Ilki, A. (2021), "Seismic collapse performance of a full-scale concrete building with lightly reinforced columns", J. Struct. Eng., 147(12), 04021207. https://doi.org/10.1061/(ASCE)ST.1943-541X.0003178.
  39. TS-500 (2000), Requirements for Design and Construction of Reinforced Concrete Structures, Turkish Standards Institute, Ankara. (in Turkish)
  40. Turkish Seismic Design Code (TSDC) (2007), Regulations for Buildings to be Constructed in Earthquake Prone Areas, Ankara, Turkey.
  41. Wang, Z., Wang, D., Smith, S.T. and Lu, D. (2012), "Experimental testing and analytical modeling of CFRP-confined large circular RC columns subjected to cyclic axial compression", Eng. Struct., 40, 64-74. https://doi.org/10.1016/j.engstruct.2012.01.004.
  42. Welch, P. (1967), "The use of fast Fourier transform for the estimation of power spectra: a method based on time averaging over short, modified periodograms", IEEE Tran. Audio Electroacoust., 15(2), 70-73. https://doi.org/10.1109/TAU.1967.1161901.
  43. Wu, Y.F. and Jiang, C. (2013), "Effect of load eccentricity on the stress-strain relationship of FRP-confined concrete columns", Compos. Struct., 98, 228-241. https://doi.org/10.1016/j.compstruct.2012.11.023.
  44. Ye, L., Yue, Q., Zhao, S. and Li, Q. (2002), "Shear strength of reinforced concrete columns strengthened with carbon-fiber-reinforced plastic sheet", J. Struct. Eng., 128, 1527-1534. https://doi.org/10.1061/(ASCE)0733-9445(2002)128:12(1527).