Earthquakes and Structures

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Improved earthquake resistant design of torsionally stiff asymmetric steel buildings

  • Kyrkos, M.T. (Department of Civil Engineering, University of Patras) ;
  • Anagnostopoulos, S.A. (Department of Civil Engineering, University of Patras)
  • Received : 2010.07.22
  • Accepted : 2011.02.08
  • Published : 2011.06.25
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Abstract

In a companion paper as well as in earlier publications, it has been shown that in asymmetric frame buildings, designed in accordance with modern codes and subjected to strong earthquake excitations, the ductility demands at the so called "flexible" edges are consistently and substantially higher than the ductility demands at the "stiff" edges of the building. In some cases the differences in the computed ductility factors between elements at the two opposite building edges exceeded 100%. Similar findings have also been reported for code designed reinforced concrete buildings. This is an undesirable behavior as it indicates no good use of material and the possibility for overload of the "flexible" edge members with a consequent potential for premature failure. In the present paper, a design modification will be introduced that can alleviate the problem and lead to a more uniform distribution of ductility demands in the elements of all building edges. The presented results are based on the steel frames detailed in the companion paper. This investigation is another step towards more rational design of non-symmetric steel buildings.

Keywords

References

  1. Anagnostopoulos, S.A., Alexopoulou, C. and Stathopoulos, K. (2010), "An answer to an important controversy and the need for caution when using simple models to predict inelastic earthquake response of buildings with torsion", Earthq. Eng. Struct. Dyn., 39(5), 521-540.
  2. Carr, A.J. (2005), RUAUMOKO manual: theory and user-guide to associated programs, Vol.1, Univ. of Canterbury, New Zealand.
  3. Chandler, A.M. and Duan, X.N. (1991), "Evaluation of factors influencing the inelastic seismic performance of torsionally asymmetric buildings", Earthq. Eng. Struct. Dyn., 20(1), 87-95. https://doi.org/10.1002/eqe.4290200107
  4. Chandler, A.M. and Duan, X.N. (1997), "Performance of asymmetric code-designed buildings for serviceability and ultimate limit states", Earthq. Eng. Struct. Dyn., 26(7), 717-735. https://doi.org/10.1002/(SICI)1096-9845(199707)26:7<717::AID-EQE672>3.0.CO;2-X
  5. Chopra, A.K. and Goel, R. (1991), "Evaluation of torsional provisions in seismic codes", J. Struct. Eng. - ASCE, 117(12), 3762-3782. https://doi.org/10.1061/(ASCE)0733-9445(1991)117:12(3762)
  6. Correnza, J.C., Hutchinson, G.I. and Chandler, A.M. (1995), "Seismic response of flexible edge elements in code-designed torsionally unbalanced structures", Eng. Struct., 17(3), 158-166. https://doi.org/10.1016/0141-0296(94)00001-A
  7. De-La-Colina, J. (1999), "Effects on torsion factors on simple non-linear systems using fully bi-directional analyses", Earthq. Eng. Struct. Dyn., 28(7), 691-706. https://doi.org/10.1002/(SICI)1096-9845(199907)28:7<691::AID-EQE834>3.0.CO;2-U
  8. De Stefano, M., Faella, G. and Ramasco, R. (1998), "Inelastic seismic response of one-way plan-asymmetric systems under bi-directional ground motions", Earthq. Eng. Struct. Dyn., 27(4), 363-376. https://doi.org/10.1002/(SICI)1096-9845(199804)27:4<363::AID-EQE728>3.0.CO;2-7
  9. De Stefano, M. and Pintucchi, B. (2008), "A review of research on seismic bahaviour of irregular building structures since 2002", Bull. Earthq. Eng., 6, 285-308. https://doi.org/10.1007/s10518-007-9052-3
  10. EC3 - Eurocode 3 (2004), "Design provisions for steel structures", Eur. Prestandard, CEN 1994; Doc.CEN/TC250/SC8/N (Latest Edition: Eurocode 8: Design of structures for earthquake resistance, European Standard EN1998-1:2004).
  11. EC8 - Eurocode 8 (2004), "Design provisions for earthquake resistance of structures", Eur. Prestandard, CEN1994; Doc.CEN/TC250/SC8/N (Latest Edition: Eurocode 8: Design of structures for earthquake resistance, European Standard EN1998-1:2004).
  12. EAK2000 (2000), "Greek code for earthquake resistant design", Greek Ministry of Environment, City Planning and Public Works 2000.
  13. Fajfar, P., Marusic, D. and Perus, I. (2004), "Influence of ground motion intensity on the inelastic torsion response of asymmetric buildings". The 13th World Conference on Earthquake Engineering, Vancouver, Canada, Paper No. 3496.
  14. Ghersi, A., Marino, E. and Rossi, P.P. (2000), "Inelastic response of multi-story asymmetric buildings", Proc.12th World Conference on Earthquake Engneering, No. 1716.
  15. Ghersi, A. and Rossi, P.P. (2006), "Influence of design procedures on the seismic response of bi-eccentric plan-asymmetric systems", Struct. Des. Tall Spec. Build., 15, 467-480. https://doi.org/10.1002/tal.307
  16. Goel, R. (1997), "Seismic response of asymmetric systems: energy-based approach", J. Struct. Eng. - ASCE, 123(11), 1444-1453. https://doi.org/10.1061/(ASCE)0733-9445(1997)123:11(1444)
  17. Humar, J.L. and Kumar, P. (1999), "Effect of orthogonal in plane structural elements on inelastic torsional response", Earthq. Eng. Struct. Dyn., 28(10), 1071-1097. https://doi.org/10.1002/(SICI)1096-9845(199910)28:10<1071::AID-EQE855>3.0.CO;2-V
  18. Karabalis, D.L., Cokkinides, G.J., Rizos, D.C., Mulliken, J.S. and Chen, R. (1994), "An interactive computer code for generation of artificial earthquake records", Comput. Civil Eng. (ASEE), 1994, K. Khozeimeh (ed.), 1122-1155.
  19. Kyrkos, M.T. and Anagnostopoulos, S.A. (2010a), "An assessment of code designed asymmetric steel buildings under strong earthquake excitations", Earthq. Struct., 2(2), 109-126.
  20. Kyrkos, M. and Anagnostopoulos, A. (2010b), "Towards earthquake resistant design of steel buildings for uniform ductility demands", Invited paper, Proc., SEMC 2010: The Fourth International Conference on Structural Engineering, Mechanics and Computation, 135-140, Cape Town, South Africa, A. Zingoni (ed.), CRC Press Balkema 2010.
  21. Marusic, D. and Fajfar, P. (2005), "On the inelastic seismic response of asymmetric buildings under bi-axial excitation", Earthq. Eng. Struct. Dyn., 34(8), 943-963. https://doi.org/10.1002/eqe.463
  22. Myslimaj, B. and Tso, W.K. (2002), "A strength distribution criterion for minimizing torsional response of asymmetric wall-type systems", Earthq. Eng. Struct. Dyn., 31(1), 99-120. https://doi.org/10.1002/eqe.100
  23. Rutenberg, A. (1998), "Behavior of irregular and complex structures - state of the art report: seismic nonlinear response of code-designed asymmetric structures", EAEE Task Group (TG)8, Proc 11th European Conference on Earthquake Engineering, Paris, Balkema.
  24. Rutenberg, A. (2002), "Behavior of irregular and complex structures - progress since 1998", EAEE Task Group (TG)8, Proc 12th European Conference on Earthquake Engineering, London, Elsevier No.832
  25. Stathopoulos, K.G. (2001), "Investigation of the inelastic response and earthquake resistant design of asymmetric buildings", Ph.D. Dissertation, University of Patras, Greece. (in Greek)
  26. Stathopoulos, K.G. and Anagnostopoulos, S.A. (2003), "Inelastic earthquake response of single-story asymmetric buildings: an assessment of simplified shear-beam models", Earthq. Eng. Struct. Dyn., 32(12), 1813-1831. https://doi.org/10.1002/eqe.302
  27. Stathopoulos, K.G. and Anagnostopoulos, S.A, (2005), "Inelastic torsion of multistory buildings under earthquake excitations", Earthq. Eng. Struct. Dyn., 34(12), 1449-1465. https://doi.org/10.1002/eqe.486
  28. Tso, W.K. and Zhu, T.J. (1992), "Design of torsionally unbalanced structural systems based on code provisions I:ductility demand", Earthq. Eng. Struct. Dyn., 21(7), 609-627. https://doi.org/10.1002/eqe.4290210704
  29. Tso, W.K. and Smith, R.S.H. (1999), "Re-evaluation of seismic torsional provisions", Earthq. Eng. Struct. Dyn., 28(8), 899-917. https://doi.org/10.1002/(SICI)1096-9845(199908)28:8<899::AID-EQE846>3.0.CO;2-Q
  30. Tso, W.K. and Myslimaj, B. (2003), "A yield displacement distribution-based approach for strength assignment to lateral force-resisting elements having strength dependent stiffness", Earthq. Eng. Struct. Dyn., 32(15), 2319-2351. https://doi.org/10.1002/eqe.328

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