بررسی موقعیت قرارگیری سازه تکدرجه آزاد غیرالاستیک با شکلپذیری ثابت در برابر نگاشت‌های حوزه نزدیک

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، ایران

2 دانشگاه صنعتی نوشیروانی بابل

چکیده

ویژگی‌های منحصربه‌فرد و آثار مخرب رکوردهای حوزه نزدیک گسل و ارائه‌ی راهکارهای مهندسی جهت پیشگیری از خساراتشان مورد توجه بسیاری از پژوهشگران می ­باشد؛ مسأله‌ی موقعیت قرارگیری سازه‌ها در برابر این رکوردها به دلیل کمبود داده ­ها کمتر مورد توجه قرار گرفته است. از این رو، در این پژوهش تمرکز بر روی تأثیر موقعیت قرارگیری سازه در میزان خسارت‌هایی است که در هنگام زلزله به آن اعمال می­ شود. به منظور بررسی در این زمینه نیازمند رکوردهای زلزله می ­باشیم که به دلیل کمبود داده های شتاب°نگاری دستگاهی، می ­توان با استفاده از تکنیک­ هایی جنبش نیرومند زمین را شبیه­ سازی کرد. با استفاده از پارامترهای گسلش به ­دست آمده برای زلزله-ی کوجائیلی ترکیه 1999، 273 شتاب­نگاشت زلزله با توجه به مختصات مکانی مختلف به وسیله ­ی تابع گرین نظری تولید شد. به منظور ارزیابی عملکرد لرزه­ای سازه ­ها از نرم ­افزار OpenSEES و 9828 تحلیل دینامیکی تاریخچه زمانی استفاده شد. سازه­ های بررسی شده، تک‌درجه آزاد غیرالاستیک با شکل‌پذیری ثابت می‌باشد که رکوردها با توجه به موقعیت قرارگیری سازه نسبت به گسل اعمال گردید و با به­ دست آوردن پاسخ ­ها، طیف­ های مربوطه به صورت کانتورهای رنگی ترسیم شد. نتایج نشان داد موقعیت پاسخ‌های بیشینه در حالت غیرالاستیک تقریباً مشابه حالت الاستیک می‌باشد. لذا به وسیله‌ی یک تحلیل الاستیک که ساده‌تر است می‌توان موقعیت‌های بحرانی‌تر را مشخص کرد؛ ایستگاه‌هایی که در پریودهای پایین مقدار بیشینه را نشان دادند دامنه‌ی بیشتر، و ایستگاه‌هایی که در پریودهای بالا مقدار بیشینه را نشان دادند پریود پالس بیشتری دارند. همچنین در تعیین موقعیت خرابی شدیدتر هر دو عامل فاصله و زاویه‌ای که سازه مورد نظر از خط گسل می‌گیرد، تأثیرگذار می‌باشند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Influence of Inelastic Constant-Ductility SDOF Location versus Near-Fault Records

نویسندگان [English]

  • Shakiba Monfaredi 1
  • Hamed Hamidi 2
  • Horr Khosravi 1
1 Graduate Student, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Iran
2 Faculty of Civil Engineering/Assistant Professor
چکیده [English]

The unique features and destructive effects of near-fault records are of high interest to many researchers; the issue of the location of structures against these records has received less attention due to the lack of data. Therefore, in this study, the focus is on the effect of the location of the structure vs. causative fault on the amount of damage. To this end, we need enough near-fault records, which can be simulated using the synthetic generation technique due to the lack of real data. Using the fault parameters obtained for the 1999-Kocaeli earthquake, 273 earthquake records were generated by different location coordinates using the theoretical-based Green's function. To evaluate the seismic performance of the structures, OpenSEES software was used to carry out 9828 dynamic time-history analyses. The studied structures are SDOF with constant ductility. The records were applied according to the position of the structure against the causative fault and the relevant spectra were drawn as colored contours. The results showed that the location of the maximum responses in the inelastic state is almost the same as in the elastic state, so the critical location can be determined by a simpler elastic analysis; Stations that showed a maximum value at low periods have a larger amplitude, and stations that showed a maximum value at high periods have a higher pulse period. Both the distance and the angle of the SDOF location are influential in determining the location of the more severe failure.

کلیدواژه‌ها [English]

  • SDOF
  • Location of the structure
  • Near-fault
  • Constant ductility
  • Bi-linear steel material
[1]  Somerville P, Graves R. Conditions that give rise to unusually large long period ground motions. The Structural Design of Tall and Special Buildings 1993;2:211–32.
[2] Nicknam A, Barkhodari MA, Hamidi Jamnani H, Hosseini A. Compatible seismogram simulation at near source site using Multi-Taper Spectral Analysis approach (MTSA). Journal of Vibroengineering 2013;15.
[3] Khaloo AR, Khosravi H, Hamidi Jamnani H. Nonlinear interstory drift contours for idealized forward directivity pulses using “modified fish-bone” models. Advances in Structural Engineering 2015;18:603–27.
[4] Abrahamson N. Seismological aspects of near-fault ground motions. 5th Caltrans Seismic Research Workshop, 1998.
[5] Heaton TH, Hall JF, Wald DJ, Halling MW. Response of high-rise and base-isolated buildings to a hypothetical Mw 7.0 blind thrust earthquake. Science 1995;267:206.
[6] Somerville PG. Development of ground motion time histories for phase 2 of the FEMA/SAC steel project. SAC Joint Venture; 1997.
[7] Liossatou E, Fardis MN. Near‐fault effects on residual displacements of RC structures. Earthquake Engineering & Structural Dynamics 2016;45:1391–409.
[8] ASCE-7. Minimum Design Loads and Associated Criteria for Buildings and Other Structures. ASCE/SEI 7-16; 2016.
[9] Ghafory-Ashtiany M, Hosseini M. Post-Bam earthquake: recovery and reconstruction. Natural Hazards 2008;44:229–41.
[10]  Ebadi P, Maghsoudi A. Case Study on Seismic Performance of Soft Stories in Short Steel Structures and Replacement of Braces with Equivalent Moment Resisting Frame. Amirkabir Journal of Civil Engineering (Amirkabir) 2017.
[11]  Madhu Girija H, Gupta VK. Scaling of constant‐ductility residual displacement spectrum. Earthquake Engineering & Structural Dynamics 2020;49:215–33.
[12]  Baéz JI, Miranda E. Amplification factors to estimate inelastic displacement demands for the design of structures in the near field. Proceedings of the 12th World Conference on Earthquake Engineering, 2000.
[13]  MacRae GA, Morrow D V, Roeder CW. Near-fault ground motion effects on simple structures. Journal of Structural Engineering 2001;127:996–1004.
[14]  Chopra AK, Chintanapakdee C. Comparing response of SDF systems to near‐fault and far‐fault earthquake motions in the context of spectral regions. Earthquake Engineering & Structural Dynamics 2001;30:1769–89.
[15]  Mavroeidis GP, Dong G, Papageorgiou AS. Near‐fault ground motions, and the response of elastic and inelastic single‐degree‐of‐freedom (SDOF) systems. Earthquake Engineering & Structural Dynamics 2004;33:1023–49.
[16]  Gillie JL, Rodriguez-Marek A, McDaniel C. Strength reduction factors for near-fault forward-directivity ground motions. Engineering Structures 2010;32:273–85.
[17]  Wang F, Li HN, Yi TH. Energy spectra of constant ductility factors for orthogonal bidirectional earthquake excitations. Advances in Structural Engineering 2015;18:1887–99.
[18]  Scott MH, Mason HB. Constant‐ductility response spectra for sequential earthquake and tsunami loading. Earthquake Engineering & Structural Dynamics 2017;46:1549–54.
[19]  De Francesco G. Constant‐ductility inelastic displacement ratios for displacement‐based seismic design of self‐centering structures. Earthquake Engineering & Structural Dynamics 2019;48:188–209.
[20]  Dong H, Han Q, Du X, Liu J. Constant ductility inelastic displacement ratios for the design of self-centering structures with flag-shaped model subjected to pulse-type ground motions. Soil Dynamics and Earthquake Engineering 2020;133:106143.
[21]  Nievas CI, Sullivan TJ. Accounting for directionality as a function of structural typology in performance‐based earthquake engineering design. Earthquake Engineering & Structural Dynamics 2017;46:791–809.
[22]  Bradley BA, Baker JW. Ground motion directionality in the 2010–2011 Canterbury earthquakes. Earthquake Engineering & Structural Dynamics 2015;44:371–84.
[23]  Pinzón LA, Mánica MA, Pujades LG, Alva RE. Dynamic soil-structure interaction analyses considering directionality effects. Soil Dynamics and Earthquake Engineering 2020;130:106009.
[24]  Grant DN, Padilla D, Greening PD. Orientation dependence of earthquake ground motion and structural response. Protection of Built Environment Against Earthquakes, Springer; 2011, p. 57–73.
[25]  Hamidi H, Khosravi H, Soleimani R. Fling-step ground motions simulation using theoretical-based Green’s function technique for structural analysis. Soil Dynamics and Earthquake Engineering 2018;115:232–45.
[26]  Sekiguchi H, Iwata T. Rupture process of the 1999 Kocaeli, Turkey, earthquake estimated from strong-motion waveforms. Bulletin of the Seismological Society of America 2002;92:300–11.
[27]  Yagi Y, Kikuchi M. Source rupture process of the Kocaeli, Turkey, earthquake of August 17, 1999, obtained by joint inversion of near‐field data and teleseismic data. Geophysical Research Letters 2000;27:1969–72.
[28]  Kojima K, Saotome Y, Takewaki I. Critical earthquake response of SDOF elastic-perfectly plastic model with viscous damping under double impulse as substitute of near-fault ground motion. Journal of Structural and Construction Engineering 2017;82. doi:10.3130/aijs.82.643.
[29]  Pourali N, Khosravi H, Dehestani M. An investigation of P-delta effect in conventional seismic design and direct displacement-based design using elasto-plastic SDOF systems. Bulletin of Earthquake Engineering 2019;17:313–36.
[30]  Hamidi H, Karbassi A, Lestuzzi P. Seismic response of RC buildings subjected to fling‐step in the near‐fault region. Structural Concrete 2020; 21(5).
[31]  McKenna F, Fenves GL, Scott MH. Opensees: Open system for earthquake engineering simulation. University of California, Berkeley, CA 2013.
[32]  Newmark NM, Hall WJ. Earthquake spectra and design: Earthquake Engineering Research Institute. Berkeley, California 1982.