Earthquakes and Structures

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Force-based seismic design of steel haunch retrofit for RC frames

  • Ahmad, Naveed (Department of Civil Engineering, UET Peshawar 2 nd Floor, Earthquake Engineering Center)
  • Received : 2019.07.25
  • Accepted : 2021.01.29
  • Published : 2021.02.25
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Abstract

The paper presents a simplified force-based seismic design procedure for the preliminary design of steel haunch retrofitting for the seismic upgrade of deficient RC frames. The procedure involved constructing a site-specific seismic design spectrum for the site, which is transformed into seismic base shear coefficient demand, using an applicable response modification factor, that defines base shear force for seismic analysis of the structure. Recent experimental campaign; involving shake table testing of ten (10), and quasi-static cyclic testing of two (02), 1:3 reduced scale RC frame models, carried out for the seismic performance assessment of both deficient and retrofitted structures has provided the basis to calculate retrofit-specific response modification factor Rretrofitted. The haunch retrofitting technique enhanced the structural stiffness, strength, and ductility, hence, increased the structural response modification factor, which is mainly dependent on the applied retrofit scheme. An additional retrofit effectiveness factor (ΩR) is proposed for the deficient structure's response modification factor Rdeficient, representing the retrofit effectiveness (ΩR=Rretrofitted /Rdeficient), to calculate components' moment and shear demands for the retrofitted structure. The experimental campaign revealed that regardless of the deficient structures' characteristics, the ΩR factor remains fairly the unchanged, which is encouraging to generalize the design procedure. Haunch configuration is finalized that avoid brittle hinging of beam-column joints and ensure ductile beam yielding. Example case study for the seismic retrofit designs of RC frames are presented, which were validated through equivalent lateral load analysis using elastic model and response history analysis of finite-element based inelastic model, showing reasonable performance of the proposed design procedure. The proposed design has the advantage to provide a seismic zone-specific design solution, and also, to suggest if any additional measure is required to enhance the strength/deformability of beams and columns.

Keywords

Acknowledgement

The author is grateful to the anonymous reviewers for kindly suggesting improvements for the manuscript, which improved the quality of the manuscript.

References

  1. ACI 318 (2005), Building code requirements for structural concrete and commentary, American Concrete Institute, Farmington Hills, U.S.A. https://doi.org/10.14359/51716937.
  2. Ahmad, N. and Masoudi, M. (2020), "Eccentric steel brace retrofit for seismic upgrading of deficient reinforced concrete frames", Bull. Earthq. Eng., 18(6), 2807-2841. https://doi.org/10.1007/s10518-020-00808-0.
  3. Ahmad, N., Masoudi, M. and Salawdeh, S. (2020), "Cyclic response and modelling of special moment resisting beams exhibiting fixed-end rotation", Bull. Earthq. Eng., 19(1), 203-240. https://doi.org/10.1007/s10518-019-00742-w.
  4. Ahmad, N., Shahzad, A., Ali, Q., Rizwan, M., Khan, A.N. (2018), "Seismic fragility functions for code compliant and noncompliant RC SMRF structures in Pakistan", Bull. Earthq. Eng., 16(10), 4675-4703. https://doi.org/10.1007/s10518-018-0377-x.
  5. Ahmad, N., Shahzad, A., Rizwan, M., Khan, A.N., Ali, S.M., Ashraf, M., Naseer, A., Ali, Q. and Alam, B. (2019), "Seismic performance assessment of non-compliant SMRF reinforced concrete frame: shake table test study", J. Earthq. Eng., 23(3), 444-462. https://doi.org/10.1080/13632469.2017.1326426.
  6. Ahmad, N., Shakeel, H. and Masoudi, M. (2019), "Design and development of low-cost HDRBs seismic isolation of structures", Bull. Earthq. Eng., 18(3), 1107-1138. https://doi.org/10.1007/s10518-018-0377-x.
  7. Akbar, J., Ahmad, N. and Alam, B. (2018), "Seismic performance of RC frames retrofitted with haunch technique", Struct. Eng. Mech., 67(1), 1-8. http://dx.doi.org/10.12989/sem.2018.67.1.001.
  8. Akbar, J., Ahmad, N. and Alam, B. (2020), "Response modification factor of haunch retrofitted reinforced concrete frames", ASCE J. Perform. Construt. Facilities, 34(6), 04020115. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001525.
  9. Arifullah, Ilyas, B. and Ahmad, N. (2019), Repair and retrofitting of seismically damaged RC frames having weaker Beam-Column Joints, Technical Report, UET Peshawar, Peshawar, Pakistan.
  10. Arzeytoon, A., Hosseini, A. and Goudarzi, A. (2016), "Seismic rehabilitation of exterior RC beam-column joints using steel plates, angles, and posttensioning rods", ASCE J. Perform. Construct. Facilities, 30(1), 04014200. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000721.
  11. AWS (2003) "Design for welding" in Welding Handbook, American Welding Society (AWS), Inc., U.S.A.
  12. BCP-SP (2007), Building Code of Pakistan: Seismic Provisions-2007. Ministry of Housing and Works, Islamabad, Pakistan.
  13. Calvi, G.M., Magenes, G. and Pampanin, S. (2002), "Experimental test on a three story R.C. frame designed for gravity only", Proceedings of the 12th European Conference on Earthquake Engineering, London, U.K.
  14. Chen, J., Shu, W. and Huang, H. (2017), "Rate-dependent progressive collapse resistance of beam-to-column connections with different seismic details", ASCE Journal of Performance of Constructed Facilities, 31(2), 04016086. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000922.
  15. Chen, T.H. (2006) Development of a low invasive seismic retrofit solution for under-designed frame systems based on a metallic haunch. Master Thesis, University of Canterbury, Christchurch, New Zealand.
  16. Genesio, G. (2012) Seismic Assessment of RC Exterior Beam-Column Joints and Retrofit with Haunches Using Post-Installed Anchors. Ph.D. Dissertation, Stuttgart University, Germany.
  17. Hussain, S. (2019) Seismic performance of RC frames retrofitted with haunch technique. Master Thesis, UET Peshawar, Pakistan.
  18. Jian, H. and Zheng, Y. (2014), "Simplified models of progressive collapse response and progressive collapse resisting capacity curve of RC beam-column substructure", J. Perform. Construct. Facilities, 28(4), 04014008. ttps://doi.org/10.1061/(ASCE)CF.1943-5509.0000492.
  19. Kappos, A.J. (1999) "Evaluation of behavior factors on the basis of ductility and overstrength studies", Eng. Struct., 21(9), 823-835. https://doi.org/10.1016/S0141-0296(98)00050-9.
  20. Kim, J. and LaFave, M. (2012), "A simplified approach to joint shear behavior prediction of RC beam-column connections, Earthq. Spectra, 28(3), 1071-1096. https://doi.org/10.1193/1.4000064.
  21. Masoudi, M. and Khajevand, S. (2020), "Revisiting flexural overstrength in RC beam-and-slab floor systems for seismic design and evaluation", Bull. Earthq. Eng., 18(11), 5309-5341. https://doi.org/10.1007/s10518-020-00907-y.
  22. Mwafy, A.M. and Elnashai, A.S. (2002), "Calibration of force reduction factors of RC buildings', J. Earthq. Eng., 6(2), 239-273. https://doi.org/10.1080/13632460209350416.
  23. Neuenhofer, A and Filippou F.C. (1997), "Evaluation of nonlinear frame finite-element models", J. Struct. Eng., ASCE, 123(7), 958-966. https://doi.org/10.1061/(ASCE)0733-9445(1997)123:7(958).
  24. Newmark, N.M. and Hall, W.J. (1982), Earthquake Spectra and Design, Earthquake Engineering Research Institute, Oakland, CA, U.S.A.
  25. Oinam, R.M. and Sahoo, D.R. (2019), "Using metallic dampers to improve seismic performance of soft-story RC frames: experimental and numerical study", J. Perform. Construct. Facilities, ASCE, 33(1), 04018108. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001254.
  26. Pampanin, S., Calvi, G.M. and Moratti, M. (2002), "Seismic behavior of R.C. beam-column joints designed for gravity only", Proceedings of the 12th European Conference on Earthquake Engineering, Paper No. 726.
  27. Pampanin, S., Christopoulos, C. and Chen, T.H. (2006), "Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildings", Earthq. Eng. Struct. Dyn., 35(14), 1739-1766. https://doi.org/10.1002/eqe.600.
  28. Pinho, R. (2007), "Nonlinear dynamic analysis of structures subjected to seismic actions", Advan. Earthq. Eng. Anal., 63-89.
  29. Priestley, M.J.N. (1997), "Displacement-based seismic assessment of reinforced concrete buildings", J. Earthq. Eng., 1(1), 157-192. https://doi.org/10.1080/13632469708962365.
  30. Qian, K. and Li, B. (2012), "Experimental and analytical assessment on RC interior beam-column subassemblages for progressive collapse", ASCE J. Perform. Construct. Facilities, 26(5), 576-589. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000284
  31. Rizwan, M., Ahmad, N. and Khan A.N. (2018), "Seismic performance of compliant and non-compliant special moment-resisting reinforced concrete frames", ACI Struct. J., 115(4), 1063-1073. https://doi.org/10.1007/978-3-211-74214-3_5.
  32. Rizwan, M., Ahmad, N. and Khan, A.N. (2019), "Seismic performance of RC frame having low strength concrete: experimental and numerical studies", Earthq. Struct., 17(1), 75-89. http://dx.doi.org/10.12989/eas.2019.17.1.075.
  33. Sharma, A., Reddy, G.R., Eligehausen, R., Genesio, G. and Pampanin, S. (2014), "Seismic response of reinforced concrete frames with haunch retrofit solution", Struct. J., 111(3), 673-684. https://doi.org/10.14359/51686625.
  34. Shedid, M.T., El-Dakhakhni, W.W. and Drysdale, R.G. (2011), "Seismic response modification factors for reinforced masonry structural walls", J. Perform. Construct. Facilities, 25(2), 74-86. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000144.
  35. Sivaselvan, M. and Reinhorn, A.M. (2001), "Hysteretic models for deteriorating inelastic structures", J. Eng. Mech., 126(6), 633-640. https://doi.org/10.1061/(ASCE)0733-9399(2000)126:6(633).
  36. Spacone E., Ciampi V. and Filippou F.C. (1996), "Mixed formulation of nonlinear beam finite element", Comput. Struct., 58(1), 71-83. https://doi.org/10.1016/0045-7949(95)00103-N.
  37. Sravanan, T.J., Rama Rao, G.V., Prakashvel, J., Gopalkrishnan, N., Lakshmanan, N. and Murty, C.V.R. (2017), "Dynamic testing of open ground story structure and in-situ evaluation of displacement demand magnifier", J. Perform. Construct. Facilities, 31(5), 04017055-1-04017055-20. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001052.
  38. Wang, B., Zhu, S., Xu, Y.L. and Jiang, H. (2017), "Seismic retrofitting of non-seismically designed RC beam-column joints using buckling-restrained haunches: design and analysis", J. Earthq. Eng., 22(7), 1188-1208. https://doi.org/10.1080/13632469.2016.1277441.
  39. Yang, Y., Liu R.Y., Xue, Y.C. and Li, H. (2017), "Experimental study on seismic performance of reinforced concrete frames retrofitted with eccentric buckling-restrained braces (BRBs)", Earthq. Struct., 12(1), 79-89. https://doi.org/10.12989/eas.2017.12.1.079.
  40. Zhang, X. and Li, B. (2018) "Shear-strength capacity assessment of corroded reinforced concrete beam-column joints", J. Perform. Construct. Facilities, 32(5), 04018067. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001216.