ارزیابی احتمالاتی رفتار فروریزش ساختمان‌های کوتاه نامتقارن در پلان

نوع مقاله : Articles

نویسندگان

1 گروه مهندسی عمران، دانشگاه آزاد اسلامی واحد سنندج

2 پژوهشکده مهندسی سازه، پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران

چکیده

این مقاله به ارزیابی احتمالاتی رفتار فروریزش ساختمان‌های کوتاه پیچشی می‌پردازد. طی زلزله‌های گذشته، بسیاری از این ساختمان‌ها در معرض خرابی‌های گسترده و حتی انهدام کلی قرار گرفته‌اند. برای این منظور، مدل‌های طراحی‌شده‌ی ساختمان‌های سه‌بعدی 3 و 6 طبقه‌ی بتن‌آرمه با برون‌محوری‌های جرمی یک‌جهته معادل صفر درصد (متقارن)، 10، 20 و 30 درصد به روش‌های بار افزون (پوش‌اور) و تاریخچه زمانی فزاینده (IDA) غیرخطی تحت اثر 21 رکورد دو مؤلفه‌ای قرار گرفته و عملکرد آنها از طریق محاسبه‌ی پارامترهای طراحی از جمله ضرایب رفتار و اضافه مقاومت، شکل‌پذیری و نیز محاسبه‌ی مقادیر حاشیه‌ی ایمنی در برابر فروریزش و منحنی‌های شکنندگی، ارزیابی شده است. نتایج نشان می‌دهد که تفاوت اساسی بین رفتار سازه‌های متقارن و نامتقارن از نظر ظرفیت شکل‌پذیری، حاشیه‌ی ایمنی در برابر فروریزش، پارامترهای طراحی و نیز منحنی‌های شکنندگی وجود دارد. همچنین نتایج حاکی از آن است که پارامترهای آیین‌نامه‌ای برای طراحی لرزه‌ای ساختمان‌های دارای برون‌محوری زیاد غیرمحافظه‌کارانه بوده و حتی با افزایش برون‌محوری سازه‌ها از یک مقدار مشخص عملکرد ایمنی جانی در آنها با توجه به معیارهای فروریزش تأمین نمی‌شود. بازنگری در پارامترهای طراحی این نوع ساختمان‌ها برحسب میزان برون‌محوری ضروری به نظر می‌رسد.

کلیدواژه‌ها


  1. Takeda, T., Sozen, M.A., and Nielson, N.N. (1970) Reinforced concrete response to simulated earthquakes. ASCE Journal of the Structural Division, 96(12), 2557-2573.
  2. Stathopoulos, K.G. and Anagnostopoulos, S.A. (2000) Inelastic earthquake response of buildings subjected to torsion. Proceedings of 12th World Conference on Earthquake Engineering, New Zealand.
  3. Paulay, T. and Priestley, M.J.N. (1992) Seismic Design of Reinforced Concrete and Masonry Buildings. John Wiley & Sons.
  4. Paulay, T. (2001) Some Design Principles relevant to Torsional Phenomena in Ductile Buildings. Journal of Earthquake Engineering, 5(3), 273-308.
  5. Hashem-Nejad, SH. and Ranjbar, M. (2007) Evaluation of the capacity spectrum method for estimating target displacement in plan-asymmetric structures. Proceedings of the 5th International Conference on Seismology and Earthquake Engineering, Tehran, Iran (in Persian).
  6. Fardis, M.N. (Editor) (2009) Seismic Design, Assessment and Retrofitting of Concrete Buildings Based on EN-Eurocode 8. Springer.
  7. Elnashai, A.S. and Sarno, L.D. (2008) Fundamentals of Earthquake Engineering. John Wiley & Sons.
  8. Bozorgnia, Y, Bertero V (Editors). (2004) Earthquake Engineering: From Seismology to Performance-based Seismic Engineering. CRS Press.
  9. Barazesh, N. and Sarvghad-Moghadam, A. (2012) Investigation and comparison of two common code-based parameters for defining torsional behavior of structures. Proceedings of the 2nd National Conference on Structural, Earthquake and Geotechnical Engineering, Tehran, Iran (in Persian).
  10. Sfura Jon, F., Hayes, J.R., and Foutch, D.A. (1999) Nonlinear seismic response of asymmetric systems, Proceeding of the 1999 Structures Congress, New Orleans, Louisiana.
  11. Hoerner, J.B. (1991) Modal coupling and earthquake response of tall buildings. Report No. EERL 71-07, Earthquake Engineering and Structural Dynamics, 20(3), 201-222.
  12. Chopra, A.K. (2008) Dynamics of Structures: Theory and Applications to Earthquake Engineering. 3rd Edition. Prentice-Hall of India.
  13. Wong, C.M. and Tso, W.K. (1994) Inelastic seismic response of torsionally unbalanced systems designed using elastic dynamic analysis. Earthquake Engineering and Structural Dynamics, 23(7), 777-790.
  14. Chopra, A.K. (2008) Dynamics of Structures: Theory and Applications to Earthquake Engineering. 3rd Edition. Prentice-Hall of India.
  15. Sedarat, H. and Bertero, V.V. (1990) Effects of Torsion on the Linear and Nonlinear Seismic Response of Structures. Earthquake Engineering Research Center, Report No. UCB/EERC-90/12.
  16. Goel, R.K. and Chopra, A.K. (1971) Inelastic Seismic Response of One-Story Asymmetric-Plan Systems: Effects of System Parameters and Yielding. Earthquake Engineering and Engineering Research Laboratory, California Institute of Technology: Pasadena, California.
  17. FEMA (2009) Quantification of Building Seismic Performance Factors, Report No. FEMA P695. Federal Emergency Management Agency: Washington, D.C.
  18. Haselton, C.B. (2006) Assessing Seismic Collapse Safety of Modern Reinforced Concrete Moment-Frame Buildings. Ph.D. Dissertation, Department of Civil and Environmental Engineering, Stanford University: Stanford, California.
  19. Zareian, F. and Krawinkler, H. (2007) Prediction of collapse-how realistic and practical is it, and what can we learn from it? The Structural Design of Tall and Special Buildings, 16(5), 633-653.
  20. Haselton, C.B. (2006) Assessing Seismic Collapse Safety of Modern Reinforced Concrete Moment-Frame Buildings, Ph.D. Dissertation, Department of Civil and Environmental Engineering, Stanford University: Stanford, California.
  21. BHRC (2005) Iranian Seismic Code of Practice (Standard No. 2800) (3rd Ed.). BHRC Press. Tehran, Iran (in Persian).
  22. Bureau for Establishing National Building Regulations (2013) Codes of Practice of Loading and Designing if Reinforced Concrete Structures. Ministry of Road and Urban Design Press. Tehran, Iran (in Persian).
  23. Ibarra, L.F., Medina, R.A., and Krawinkler, H. (2005) Hysteretic models that incorporate strength and stiffness deterioration. International Journal for Earthquake Engineering and Structural Dynamics, 34(12), 1489-1511.
  24. Panagiotakos, T.B. and Fardis, M.N. (2001) Deformation of reinforced concrete members at yield and ultimate. ACI Structural Journal, 98(2), 135-148.
  25. Berry, M., Parrish, M., and Eberhard, M. (2004) PEER Structural Performance Database User's Manual. Pacific Earthquake Engineering Research Center: University of California, Berkeley.
  26. Pacific Earthquake Engineering research Center. OpenSees, Open System for Earthquake Engineering Simulation. (2015-Last update), [Online]. Available: http://opensees.berkeley.edu [2012, Feb. 16]
  27. Manie, S. and Moghadam, A.S. (2012) Experiences acquired through nonlinear modeling for collapse safety assessment of 3D RC structures with irregularities in plan. Proceedings of 15th World Conference on Earthquake Engineering, Lisbon, Portugal, 1561.
  28. Vamvatsikos, D. and Cornell, C.A. (2001) Tracing and Post-Processing of IDA Curves: Theory and Software Implementation. Report No. RMS-44, RMS Program: Stanford University, Stanford.
  29. ASCE (2007) Seismic Rehabilitation of Existing Buildings. ASCE Standard ASCE/SEI 41-06. American Society of Civil Engineers: Reston Virginia.
  30. FEMA (2005) Improvement of Nonlinear Static Seismic Analysis Procedures. FEMA 440. Federal Emergency Management Agency: Washington, D.C.
  31. Vidic, T., Fajfar, P., and Fischinger, M. (1994) Consistent inelastic design spectra: strength and displacement. Earthquake Engineering and Structural Dynamics 23, 502-521.
  32. ASCE (2010) Minimum Design Loads for Buildings and Other Structures. ASCE Standard ASCE/SEI 7-05. American Society of Civil Engineers: Reston, Virginia.
  33. CEN (2004a) European Standard EN 1998-1:2004 Eurocode 8: Design of Structures for Earthquake
  34. Resistance, Part 1: General Rules, Seismic Actions and Rules for Buildings. Comite Europeen de
  35. Normalisation, Brusells.