Earthquakes and Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Simplified elastic design checks for torsionally balanced and unbalanced low-medium rise buildings in lower seismicity regions

  • Lam, Nelson T.K. (Department of Infrastructure Engineering, The University of Melbourne) ;
  • Wilson, John L. (Faculty of Science, Engineering and Technology, Swinburne University of Technology) ;
  • Lumantarna, Elisa (Department of Infrastructure Engineering, The University of Melbourne)
  • Received : 2016.02.08
  • Accepted : 2016.10.11
  • Published : 2016.11.25
⟨ Previous Next ⟩

Abstract

A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

Keywords

Acknowledgement

Grant : Collapse Assessment of Reinforced Concrete Buildings in Regions of Lower Seismicity

Supported by : Australian Research Council (ARC)

References

  1. Abrahamson, N., Silva, W.J. and Kamai, R. (2014), "Summary of the ASK14 ground motion relation for active Crustal regions", Earthq. Spectra, 30(3), 1025-1055. https://doi.org/10.1193/070913EQS198M
  2. 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
  3. Bosco, M., Ghersi, A. and Marino, E.M. (2013) "Comparison of nonlinear static methods for the assessment of asymmetric buildings", Bull. Earthq. Eng., 11(6), 2287-2308. https://doi.org/10.1007/s10518-013-9516-6
  4. Boore, D.M., Stewart, J.P., Seyhan, E. and Atkinson, G.M. (2014), "NGA-West2 equations for predicting PGA, PGV, and 5% damped PSA for shallow crustal earthquakes", Earthq. Spectra, 30(3), 1057-1085. https://doi.org/10.1193/070113EQS184M
  5. Campbell, K.W. and Bozorgnia, Y. (2014), "NGA-West2 Ground Motion Model for the average horizontal components of PGA, PGV, and 5% damped linear acceleration response spectra", Earthq. Spectra, 30(3), 1087-1115. https://doi.org/10.1193/062913EQS175M
  6. Chiou, B.S.J. and Youngs, R.R. (2014), "Update of the Chiou and Youngs NGA model for the average horizontal component of peak ground motion and response spectra", Earthq. Spectra, 30(3), 1117-1153. https://doi.org/10.1193/072813EQS219M
  7. Computers & Structures Inc. (2013), User's Guide ETABS 2013: Integrated Building Design Software, Computers & Structures, Inc, Berkeley, California, USA.
  8. Cimellaro, G.P., Giovine, T. and Lopez-Garcia, D. (2014), "Bi-directional pushover analysis of irregular structures", J. Struct. Eng., 140(9), 04014059. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001032
  9. D'Ambrisi, A., De Stefano, M. and Tanganelli, M. (2009) "Use of pushover analysis for predicting seismic response of irregular buildings: A case study", J. Earthq. Eng., 13(8), 1089-1100. https://doi.org/10.1080/13632460902898308
  10. EN 1998-1 (2004), Eurocode 8: Design of Structures for Earthquake Resistance - Part 1: General Rules, Seismic Actions and Rules for Buildings, BSI.
  11. Kafle, B., Lam, N., Gad, E.F. and Wilson, J. (2011), "Displacement controlled rocking behaviour of rigid objects", Earthq. Eng. Struct. Dyn., 40(15), 1653-1669. https://doi.org/10.1002/eqe.1107
  12. Lam, N.T.K. and Wilson, J.L. (2004), "Displacement modelling of intraplate earthquakes", ISET J. Earthq. Technol., 1, 15-52
  13. Lam, N.T.K., Wilson, J.L. and Hutchinson, G.L. (1997), "Review of the torsional coupling of asymmetrical wall-frame building", Eng. Struct., 19(3), 233-246. https://doi.org/10.1016/S0141-0296(96)00059-4
  14. Lee, H.S. and Hwang, K.R. (2015), "A new nethodology in seismic torsion design of building structures", Proceedings of the ASEM'15 conference, August, Seoul.
  15. Lumantarna, E., Lam, N. and Wilson, J. (2013), "Displacement-controlled behavior of asymmetrical singlestory building models", J. Earthq. Eng., 17(6), 902-917. https://doi.org/10.1080/13632469.2013.781557
  16. Lumantarna, E., Lam, N., Wilson, J. and Griffith, M. (2010), "Inelastic displacement demand of strengthdegraded structures", J. Earthq. Eng., 14(4), 487-511. https://doi.org/10.1080/13632460903336910
  17. Magliulo, G., Maddaloni, G. and Cosenza, E. (2012), "Extension of N2 method to plan irregular buildings considering accidental eccentricity", Soil Dyn. Earthq. Eng., 43, 69-84. https://doi.org/10.1016/j.soildyn.2012.07.032
  18. PEER (2015), NGA-East: median ground-motion models for the Central and Eastern North America Region, PEER Report No. 2015/04, Pacific Earthquake Engineering Research Center, University of California, Berkeley.
  19. Poursha, M., Khoshnoudian, F. and Moghadam, A.S. (2014), "The extended consecutive modal pushover procedure for estimating the seismic demands of two-way unsymmetric-plan tall buildings under influence of two horizontal components of ground motions", Soil Dyn. Earthq. Eng., 63, 162-173. https://doi.org/10.1016/j.soildyn.2014.02.001
  20. Standards Australia (2007), AS 1170.4-2007 Structural Design Actions, Part 4: Earthquake Actions in Australia, Standards Australia, Sydney, Australia.
  21. Standards New Zealand (2004), NZS 1170.5 Structural Design Actions, Part 5: Earthquake Actions-New Zealand, Standards New Zealand, Wellington, New Zealand.
  22. Stathopoulos, K.G. and Anagnostopoulos, S.A. (2000), "Inelastic earthquake response of buildings subjected to torsion", Proceedings of the 12th World Conference on Earthquake Engineering, Auckland, February.
  23. Stathopoulos, K.G. and Anagnostopoulos, S.A. (2003), "Inelastic earthquake response of single-story Earthquake induced torsion in buildings: critical review and state of the art asymmetric buildings: an assessment of simplified shear-beam models", Earthq. Eng. Struct. Dyn., 32, 1813-1831. https://doi.org/10.1002/eqe.302
  24. Sofi, M., Lumantarna, E., Helal, J., Letheby, M., Rezapour, M., Duffield, C.F. and Hutchinson, G.L. (2013), "The effects of building parameters on seismic inter-storey drifts of tall buildings", Proceedings of the 2013 Australian Earthquake Engineering Society Conference. Australian Earthquake Engineering Society Conference (AEES), Tasmania, November.
  25. Tsicnias, T.G. (1981), "Coupled lateral and torsional earthquake response of buildings with rigid floor diaphragms", Ph.D Thesis, University of London.
  26. Wilson, J. and Lam, N. (2006), "Earthquake design of buildings in Australia by velocity and displacement principles", Aust. J. Struct. Eng., 6(2), 103-118. https://doi.org/10.1080/13287982.2006.11464948

Cited by

  1. Numerical study on the effects of seismic torsional component on multistory buildings vol.13, pp.1, 2016, https://doi.org/10.12989/eas.2017.13.1.009
  2. Methods of analysis for buildings with uni-axial and bi-axial asymmetry in regions of lower seismicity vol.15, pp.1, 2016, https://doi.org/10.12989/eas.2018.15.1.081
  3. A simplified design approach for modelling shear force demand on tower walls supported on a transfer structure in regions of lower seismicity vol.15, pp.1, 2016, https://doi.org/10.12989/eas.2018.15.1.097
  4. Estimation of elastic seismic demands in TU structures using interactive relations between shear and torsion vol.19, pp.1, 2016, https://doi.org/10.12989/eas.2020.19.1.59
  5. Fast Checking of Drift Demand in Multi-Storey Buildings with Asymmetry vol.11, pp.1, 2016, https://doi.org/10.3390/buildings11010013
  6. SSI effects on the redistribution of seismic forces in one-storey R/C buildings vol.20, pp.3, 2021, https://doi.org/10.12989/eas.2021.20.3.261