Earthquakes and Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Torsional sensitivity criteria in seismic codes

  • Athanatopoulou, Asimina M. (Department of Civil Engineering, Aristotle University of Thessaloniki, University Campus) ;
  • Manoukas, Grigorios E. (Department of Civil Engineering, Aristotle University of Thessaloniki, University Campus)
  • Received : 2021.04.11
  • Accepted : 2021.07.10
  • Published : 2021.07.25
⟨ Previous Next ⟩

Abstract

Buildings with fundamental vibration mode dominated by torsion are characterized in the literature as "torsionally flexible" or "torsionally sensitive". Given that the seismic behavior of such buildings may be governed by torsion, modern seismic codes prescribe simplified criteria in order to identify them. The objective of the present paper is to evaluate the relevant criteria adopted by four seismic codes. For this purpose, the accuracy of the aforementioned criteria is theoretically investigated with the aid of a well-established analytical criterion based on single-storey one-way asymmetric models. In addition, in order to quantify the shortcomings of some criteria, three illustrative examples are presented. The whole study leads to useful conclusions which contribute to the clarification of some crucial aspects of the torsional seismic response of buildings.

Keywords

References

  1. Abebe, B.H. and Lee J.S. (2019), "Accounting for torsional response in Direct Displacement-based Design of planasymmetric reinforced concrete frame buildings", KSCE J. Civil Eng., 23(3), 1190-1206. https://doi.org/10.1007/s12205-019-1739-x.
  2. Aldeka, A.B., Chan, A.H.C. and Dirar, S. (2014), "Response of non-structural components mounted on irregular RC buildings: Comparison between FE and EC8 predictions", Earthq. Struct., 6(4), 351-373. http://dx.doi.org/10.12989/eas.2014.6.4.
  3. Alecci, V., De Stefano, M., Galassi, S., Lapi, M. and Orlando M. (2019), "Evaluation of the American approach for detecting plan irregularity", Advan. Civil Eng., Article ID 2861093, https://doi.org/10.1155/2019/2861093.
  4. Aliakbari, F., Garivani, S. and Sahmari, A. (2020), "Determination of torsional irregularity in response spectrum analysis of building structures", Struct. Eng. Mech., 74(5), 699-709. http://dx.doi.org/10. 12989/sem.2020.74.5.699. https://doi.org/10.12989/sem.2020.74.5.699
  5. Anagnostopoulos, S.A., Kyrkos, M.T. and Stathopoulos, K.G. (2015), "Earthquake induced torsion in buildings: critical review and state of the art", Earthq. Struct., 8(2), 305-377. https://doi.org/10.12989/ EAS.2015.8.2.305.
  6. Anastassiadis, K.K. (1989), Earthquake Resistant Structures, Volume I, Computer Technics, Thessaloniki, Greece.
  7. Anastassiadis, K.K. and Athanatopoulou, A.M. (1996), "Torsional sensitivity of buildings and seismic codes", Proceedings of the 12th Hellenic Conference on Reinforced Concrete Structures, III:135-44, Limassol, Cyprus, October.
  8. Annigeri, S., Mittal, A.K. and Jain A.K. (1996), "Uncoupled frequency ratio in asymmetric buildings", Earthq. Eng. Struct. Dyn., 25(8), 871-881. https://doi.org/10.1002/(SICI)1096-9845(199608)25:8<871::AID-EQE593>3.0.CO;2-3.
  9. ASCE/SEI 7-10 (2016), Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers (ASCE); Reston, U.S.A.
  10. Bhasker, R. and Menon, A. (2020), "Torsional irregularity indices for the seismic demand assessment of RC moment resisting frame buildings", Struct., 26, 888-900. https://doi.org/10.1016/j.istruc.2020.05.018.
  11. Chopra, A.K. and Goel, R.K. (2004), "A modal pushover analysis procedure to estimate seismic demands for unsymmetric-plan buildings", Earthq. Eng. Struct. Dyn., 33, 903-927. https://doi.org/10.1002/eqe.418.
  12. Chopra, A.K. and Goel, R.K. (2006), "Evaluation of the modal pushover analysis procedure for unsymmetric-plan buildings", Proceedings of the 1st European Conference of Earthquake Engineering and Seismology, Geneva, Switzerland, September.
  13. De Stefano, M., Tanganelli, M. and Viti, S. (2015), "Torsional effects due to concrete strength variability in existing buildings", Earthq. Struct., 8(2), 379-399. http://dx.doi.org/10.12989/eas.2015.8.2.379.
  14. EAK 2003 (2003), Hellenic Seismic Code, Earthquake Planning and Protection Organization (EPPO), Athens, Greece.
  15. Efstathakis, N.C. and Papanikolaou, V.K. (2017), "A retrofitting method for torsionally sensitive buildings using evolutionary algorithms", Earthq. Struct., 12(3), 309-319. https://doi.org/10.12989/eas.2017.12.3. 309.
  16. Etedali, S. and Sohrabi, M.R. (2016), "A proposed approach to mitigate the torsional amplifications of asymmetric baseisolated buildings during earthquakes", KSCE J. Civil Eng., 20(2), 768-776. https://doi.org/10.1007/s12205-015-0325-0.
  17. Eurocode 8 (2004), Design of structures for earthquake resistance - Part 1: General Rules, Seismic Actions and Rules for Buildings, European Committee for Standardization (CEN); Brussels, Belgium.
  18. Georgoussis, G.K. (2014), "Modified seismic analysis of multistory asymmetric elastic buildings and suggestions for minimizing the rotational response", Earthq. Struct., 7(1), 39-55. https://doi.org/10.12989/eas.2014.7.1.039.
  19. Gursoy, S. (2014), "Comparative investigation of the costs and performances of torsional irregularity structures under seismic loading according to TEC", Comput. Concrete, 14(4), 405-417. http://dx.doi.org/10. 12989/cac.2014.14.4.405. https://doi.org/10.12989/cac.2014.14.4.405
  20. Ilerisoy, Z.Y. (2019), "Discussion of the structural irregularities in the plan for architectural design within the scope of earthquake codes", Periodica Polytechnica Architecture, 50(1), 50-62. https://doi.org/10.3311/PPar.13040.
  21. NEAK 1992 (1992), New Hellenic Seismic Code, Earthquake Planning and Protection Organization (EPPO), Athens, Greece.
  22. Ozmen, G. and Gulay, F.G. (2002), "An investigation of torsionally irregular multi-story buildings under earthquake loading", Struct. Eng. Mech., 14(2), 237-243. http://dx.doi.org/10.12989/sem.2002.14.2.237.
  23. Roy, J., Tremblay, R. and Leger, P. (2015), "Torsional effects in symmetrical steel buckling restrained braced frames: evaluation of seismic design provisions", Earthq. Struct., 8(2), 423-442. https://doi.org/10.12989/ eas.2015.8.2.423.
  24. NZS 1170.5:2004 (2004), Structural Design Actions, Part 5, Earthquake Actions - New Zealand, Standards New Zealand, New Zealand.
  25. Yoon, Y.S. and Stafford Smith, B. (1995), "Estimating period ratio for predicting torsional coupling", Eng. Struct., 17(1), 52-62. https://doi.org/10.1016/0141-0296(95)91040-8.
  26. Zhang, C., Alam, Z. and Samali, B. (2016), "Evaluating contradictory relationship between floor rotation and torsional irregularity coefficient under varying orientations of ground motion", Earthq. Struct., 11(6), 1027-1041. https://doi.org/10.12989/eas.2016.11. 6.1027.