ارزیابی شاخص قابلیت اطمینان قاب‌های خمشی بزرگ‌دهانه فولادی تحت اثر مؤلفه قائم زلزله

نوع مقاله : Articles

نویسندگان

1 دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران

2 دانشکده فنی مهندسی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات، تهران، ایران

3 پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران، ایران

چکیده

زلزله‌های حوزه نزدیک عموماً دارای مؤلفه قائم بزرگتری نسبت به مؤلفه افقی می‌باشند و با همین ویژگی از زلزله‌های حوزه دور متمایز می‌شوند. این موضوع در قاب‌های بزرگ‌دهانه دارای اهمیت بیشتری هستند. در این پژوهش اثر مؤلفه‌های افقی و قائم زلزله در قاب های بزرگ دهانه، با شبیه‌سازی دو نوع سازه  با دهانه های مختلف، با استفاده از نرم‌افزارهای اجزاء محدود مورد بررسی قرار گرفته است. به این گونه که ابتدا سازه ها را تحت اثر مؤلفه‌های افقی زلزله قرار داده و در مرحله بعد علاوه بر مؤلفه‌های افقی، مؤلفه قائم زلزله نیز وارد شده و در هر حالت عملکرد آن مورد بررسی قرار گرفته است. برای بررسی عملکرد سازه نیز مطابق دستورالعمل بهسازی لرزه‌ای، از تحلیل‌های استاتیکی و دینامیکی خطی و غیرخطی استفاده شده است. در بخش پایانی مقاله که با هدف ارزیابی قابلیت اطمینان سازه صورت گرفته است، مقادیر افزایش لنگر، برش، نیروی محوری ستون ها، افت میان دهانه تیرها و ... بررسی شده و با استفاده از یک نرم‌افزار آماری مناسب، قابلیت اطمینان سازه نسبت به پارامترهای مذکور محاسبه شده است.

کلیدواژه‌ها

عنوان مقاله [English]

Evaluation of Reliability Index for Long Span Steel Moment Frames Subjected to Vertical Earthquake Component

نویسندگان [English]

  • Panam Zarfam 2
  • Mahmood Hosseini 3
2 Technical Faculty, Science and Research Branch of the Islamic Azad University (IAU), Tehran, Iran
3 Structural Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
چکیده [English]

Records in the near-fault areas indicate the strong vertical ground motion. Near-fault earthquakes are different from far-fault earthquakes due to the adverse effect oftheir vertical component, which can be very destructive for long span frames. The Vertical Component of earthquake is different from the horizontal component. Vertical component of earthquake occurs when the compression P waves separate. Whereas the horizontal component occurs as the shear S waves separate. The frequency content of vertical component of earthquake is higher than the horizontal component. The natural frequency of structures in the vertical direction is more than that of the horizontal direction. These factors may cause the resonance in the structures. The first step in the examination of the effects of vertical component of an earthquake on structures is identifying the stimulating source of vertical component of the earthquake, response spectrum of the vertical component and affecting parameters on the vertical component.In this research, the effect of horizontal and vertical components of earthquakes has been investigated in long span building frames by modeling two types of such structures with various openings sizes in a powerful finite element software. For this purpose, in the first phase of the study, the structures have first been evaluated under the effect of horizontal component of earthquake alone, and then, the vertical component of earthquakes has been added and performance of the structures has been evaluated again. To evaluate the performance of structures, both linear and nonlinear as well as static and dynamic analyses according to the seismic rehabilitation of structures guidelines have been performed. In the second phase of the study, for more confident evaluation, the reliability indices as suitable tool, recommended in recent researches, have been used. For this purpose, the amounts of moment, shear force, axial force of columns, and deflection of the long span beams have been calculated, and the corresponding reliability indices have been obtained by using an appropriate statistical software.

کلیدواژه‌ها [English]

  • Seismic Reliability
  • Reliability Indices
  • Vertical Component of Earthquake Ground Motion
  • Long Span Building Frames

مراجع

  1. Elnashai, A., Spencer, B., Kuchma, D., Kim, S.J., Burdette, N., Holub, C., Gonzales, J., Nakata, N., Yang, G., Gan, Q. (2005) Analysis and Distributed Hybrid Simulation of Shear-Sensitive RC Bridges Subjected to Horizontal and Vertical Earthquake Ground Motion. Technical Memorandum of Public Works Research Institute. 3983, 351-368.
  2. Silva, W. (1997) Characteristic of vertical ground motions for application to engineering design. Proc. of FHWA/NCEER Workshop on the National Representation of Seismic Ground Motion for New and Existing Highway Facilities, Tech. Rep. No. NCEER-97-0010, National Center for Earthquake Engineering Research, State University of New York at Buffalo N.Y., 205-252.
  3. Yang, J. and Lee, C.M. (2007) Characteristics of vertical and horizontal ground motion recorded during the Niigata-Ken Chuetsu, Japan Earthquake of 23 October 2004. Engineering Geology, 94, 50-64.
  4. Galal, K. and Ghobarah, A. (2006) Effect of near-fault earthquakes on North American nuclear design spectra. Nuclear Engineering and Design, 236(18), 1928-1936.
  5. Naderi, M., Rezaeian, A., and Tanoorsaz, M. (2010) Evaluation of damage index of steel moment resistance frames before and after seismic rehabilitation by steel braces and shear wall. Journal of Structural Steel Association, Iran, Issue VIII, Pages 17-31 (in Persian).
  6. Haran Pragalath, D.C., Davis, P.R., Sarkar, P., and Priyadharshini, M. (2014) Seismic Reliability Assessment of RC Frame in a High Seismic Zone-India, International Journal of Emerging Technology and Advanced Engineering, ISSN 2250-2459, 4(Special Issue 4).
  7. Hosseini, M. and Sadr Ara, M. (2017) The effect of vertical component of earthquake on the long span frames. Journal Sharif, 33(1-2), 105-111 (in Persian).
  8. Ruiz, D. and Sarria, A. (2004) Response of large span steel frames subjected to horizontal and vertical seismic motions. Proceedings 13th World Conference on Earthquake Engineering, Vancouver, B.C. Canada, August.
  9. Hosseini, M. and Firoozi Nezamabadi, M. (2004) A Study of the Effects of the Vertical Ground Acceleration on the Seismic Response of Steel Buildings. 13th WCEE. Vancouver, B.C., Canada, Paper No. 2377.
  10. Haldar, A. and Reyes-Salazar, A. (2000) Dissipation of energy in steel frames under dynamic loading. Proceedings 12th World Conference on Earthquake Engineering, New Zealand, Paper No 0458.
  11. Mazza, F. and Vulcano, A. (2004) Effects of the vertical acceleration on the response of base-isolated structures subjected to near-fault ground motions. Proceedings 13th World Conference on Earthquake Engineering, Vancouver, B.C. Canada, August.
  12. Ghafory-Ashtiany, M. and Singh, M.P. (1986) Structural response for six correlated earthquake components. Earthquake Engineering and Structural Dynamics, 14, 103-119.
  13. Graizer, V. and Kalkan, E. (2007) Multi-Component Ground Motion Response Spectra for Coupled Horizontal, Vertical, Angular Accelerations, and Tilt. ISET Journal of Earthquake Technology, Paper No. 485. 44(1), 259–284.
  14. Nasirian, M. and Yahyai, M. (2014) Retrofitting steel structures under near faults earthquakes with the effect of the vertical component of earthquake. Seventh National Congress of Civil Engineering, Department of Civil Engineering, Babol, Iran.
  15. Koshtegar, B. and Miri, M. (2014) Providing a New Method For Assessing The Reliability of Structures. Journal of Modeling in Engineering, 12, Paper No. 36 (in Persian).

فایل ها

اشتراک گذاری

ارجاع به این مقاله

آمار