The Expected Seismic Fragility of Code-Conforming RC Moment Resisting Frames under Twin Seismic Events

Document Type : Research Article

Authors

1 Associate Professor, Structural Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

2 M.Sc. Graduate, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

Abstract

Height of the buildings directly affects the seismic performance and behavior of the structure during the earthquakes. This parameter is also significant when the structure is excited by two consequent ground motions. This paper presents the results of a study on the effect frame height on the seismic performance under two successive strong ground motions. It has been shown that, when the consequence of the first event remain in the structure as damage, the building often shows different dynamic characteristics as well as more vulnerability during the second seismic event. Three RC moment resisting frames with 4, 8 and 15 stories are designed based on the latest version of Iranian code of seismic design of buildings referred as Standard No. 2800 (STD 2800). The frames are then simulated in OpenSees software to perform nonlinear dynamic analysis. Twenty natural ground motion sequences each including two seismic events were selected from previous studies for the purpose of nonlinear incremental dynamic analysis. Maximum inter-story drift was employed as a damage index, to capture the performance of the RC frames under sequences. The accepted performance level for collapse level was taken from Iranian instruction for seismic rehabilitation of existing buildings, PBO-Publication No. 360, 2007, which is similar to ASCE 41-13. Seismic fragility values are calculated for the buildings under the second event when being damaged in first event. Assuming a log-normal distribution for failure probability function, corresponding values of median, μ and standard deviation, β, for each case are calculated and discussed for frames with different heights. The results indicate how the main parameters of the seismic fragility function may differ with frame height.

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  1. Mahin, S.A. (1980) Effects of duration and aftershocks on inelastic design earthquakes. Proceedings of the 7th World Conference on Earthquake Engineering, 5, 677-680. Retrieved from: https://www.academia.edu/22767890/Effects_ of_multiple_earthquakes_on_inelastic_structural_ response.
  2. Aschheim, M. and Black, E. (1999) Effects of prior earthquake damage on response of simple stiffness-degrading structures. Engineering Spectra, 15(1), 1-24. https://earthquakespectra.org/doi/abs/ 10.1193/1.1586026.
  3. Amadio, C., Fragiacomo, M., and Rajgelj, S. (2003) The effects of repeated earthquake ground motions on the nonlinear response of SDOF systems. Earthquake Engineering and Structural Dynamics, 32(2), 291-308.
  4. Fragiacomo, M., Amadio, C., and Macorini, L. (2004) Seismic response of steel frames under repeated earthquake ground motions. Engineering Structures, 26(13), 2021-2035. Retrieved from: https://www.sciencedirect.com/science/article/pii/S0141029604002639.
  1. Li, Q. and Ellingwood, B. (2007) Performance evaluation and damage assessment of steel frame buildings under main shock-aftershock earth- quake sequences. Earthquake Engineering and Structural Dynamics, 36, 405-427, retrieved from: https://www.sciencedirect.com/science/article/pii/ S0267726115000287.
  2. Hatzigeorgiou, G.D. and Beskos, D.E. (2009) Inelastic displacement ratios for SDOF structures subjected to repeated earthquakes. Engineering Structures31(11), 2744-2755. Retrieved from: https://www.sciencedirect.com/science/article/pii/S0141029609002284.
  3. Hatzigeorgiou, G.D. (2010) Behavior factors for nonlinear structures subjected to multiple near-fault earthquakes. Computers and Structures. 88, 309-321. Retrieved from: https://www.sciencedirect. com/science/article/abs/pii/S004579490900279X.
  4. Ruiz-García, J. (2012) Mainshock-aftershock ground motion features and their influence in building's seismic response. Journal of Earthquake Engineering, 16(5), 719-737. Retrieved from: https://www.tandfonline.com/doi/full/10.1080/13632469.2012.663154.
  5. Ates, S., Kahya, V., Yurdakul, M., and Adanur, S. (2013) Damages on reinforced concrete buildings due to consecutive earthquakes in Van. Soil Dynamics and Earthquake Engineering, 53, 109-118, Retrieved from: https://www.sciencedirect. com/science /article/pii/S0267726113001395.
  6. Hatzivassiliou, M. and Hatzigeorgiou, G.D. (2015) Seismic sequence effects on three-dimensional reinforced concrete buildings. Soil Dynamics and Earthquake Engineering, 72, Retrieved from: 77-88. https://www.sciencedirect.com/science/article/ pii/S0267726115 000287.
  7. Tesfamariam, S., Goda, K., and Mondal, G. (2015) Seismic vulnerability of reinforced concrete frame with unreinforced masonry infill due to main shock–aftershock earthquake sequences. Earth-quake Spectra, 31(3), 1427-1449. Retrieved from: https://earthquakespectra.org/doi/abs/10.1193/042313EQS111M.
  8. Raghunandan, M., Liel, A.B., and Luco, N. (2015) Aftershock collapse vulnerability assessment of reinforced concrete frame structures. Earthquake Engineering & Structural Dynamics, 44(3), 419-439. Retrieved from: https://onlinelibrary.wiley. com/doi/abs/10.1002/eqe.2478.
  9. Hosseinpour, F. and Abdelnaby, A.E. (2017) Effect of different aspects of multiple earthquakes on the nonlinear behavior of RC structures. Soil Dynamics and Earthquake Engineering92, 706-725. Retrieved from: https://www.sciencedirect.com/ science/article/pii/ S0267726116304778.
  10. Standard No. 2800 (2005) Iranian Code of Practice for Seismic Resistant Design of Buildings. Third Revision, Building and Housing Research Center, Tehran. Retrieved from: http://iisee. kenken.go.jp/worldlist/26_Iran/Iran%20National%20Seismic%20Code_2007_3rd%20Version_English.
  11. Karsan, I.D. and Jirsa, J.O. (1969) Behavior of concrete under compressive loading. Journal of the Structural Division. Proceeding of the American Society of Civil Engineers, 95(ST12), 2543-2563.
  12. Mander, J.B., Priestley, M.J., and Park, R. (1988) Theoretical stress-strain model for confined concrete. Journal of structural engineering, 114(8), 1804-1826.
  13. Vamvatsikos, D. and Cornell, C.A. (2002) Incremental dynamic analysis. Earthquake Engineering and Structural Dynamics, 31(3), 491-514.
  14. ASCE (2013) ASCE/SEI 41-13: Seismic Evaluation and Retrofit of Existing Buildings. Reston, Virginia: American Society of Civil Engineers.

19. PBO Planning and Management Organization of Iran (2007) Iranian Instruction for Seismic Rehabilitation of Existing Buildings (Publication No. 360). Management and Planning Organization of Iran.