ارزیابی فروریزش لرزه‏ ای سازه‏ های دارای حرکت گهواره‏ ای با مهاربند‏‏های کمانش ناپذیر تحت اثر زلزله‌های پوسته‌ای و فرورانشی

نوع مقاله : علمی - پژوهشی

نویسندگان

گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران

چکیده

سازه ‏های با مهاربندهای کمانش ناپذیر (BRBFs) ممکن است در یک طبقه تمرکز دریفت داشته باشند زیرا مهاربند کمانش ناپذیر در یک طبقه معین تسلیم می‏ شود و سختی آن طبقه به طور قابل توجهی کاهش می ‏یابد. برای کنترل تمرکز خسارت در یک طبقه و ایجاد توزیع یکنواخت دریفت در ارتفاع سازه، یک سیستم نوین تحت عنوان سازه‌های دارای حرکت گهواره‎ ای با مهاربندهای کمانش ناپذیر (RBRBFs) مورد استفاده قرار گرفت. در سازه‌های RBRBF بر خلاف قاب‏ های مهاربندی متداول ، مهاربندهای یک سمت دهانه مهاربندی شده همراه با ستون ‏های مجاور آنها و المان ‏های رابط بخشی از یک سیستم خرپای قائم الاستیک هستند که در پایه مفصلی می ‏باشد و به ‏گونه ‏ای طراحی می‏ شود که تا نزدیک فروریزش سازه الاستیک باقی بماند، خرپای قائم الاستیک مانند یک تکیه‌گاه قوی در برابر تمایل قاب‌ مهاربندی به تمرکز خسارت در هنگام زلزله مقاومت می‌کند. سمت دیگر دهانه مهاربندی شده مجهز به مهاربند‏های کمانش ناپذیر می ‏باشد که نقش مستهلک کننده انرژی را دارد و می ‏تواند وارد محدوده رفتار غیرالاستیک شود. نوآوری این مقاله بررسی فروریزش لرزه‏ ای این سیستم سازه‏ ای جدید تحت اثر زلزله ‏های فرورانشی است که مدت زمان حرکات شدید بالاتری در مقایسه با زلزله‏ های پوسته‏ ای دارند. برای این منظور، ساختگاه سازه‌های مورد مطالعه در شهر سیاتل در نظر گرفته شده است که در معرض زلزله‏ های پوسته‌ای و همچنین زلزله‏ های فرورانشی قرار دارد. نتایج نشان داد که سازه‌های RBRBF طراحی شده با استفاده از روش طراحی مبتنی بر تغییرمکان می ‏توانند به طور موثر تمرکز دریفت را کاهش دهند و به طور قابل توجهی تحت هر دو مجموعه رکوردهای پوسته ‎ای و فرورانشی عملکرد بالاتری از نظر فروریزش در مقایسه با سازه‌های BRBF دارند. به علاوه، تمامی سازه‌ها تحت رکوردهای فرورانشی ظرفیت فروریزش کم‌تری نسبت به رکوردهای پوسته‌ای دارند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Seismic collapse assessment of rocking buckling restrained braced frames subjected to crustal and subduction ground motion records

نویسندگان [English]

  • Mehran Mirzaei
  • Mansoor Yakhchalian
Department of Civil Engineering, Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin, Iran
چکیده [English]

Buckling restrained braced frames (BRBFs) may have damage concentration in one or few stories during severe seismic excitations, because buckling restrained brace (BRB) yields in a certain story and the stiffness of that story is significantly reduced. Drift concentration is undesirable because it can lead to general instability resulting from the P-Δ effects or residual drift. For controlling damage concentration and achieving a uniform distribution of drift in all stories, a new system entitled rocking buckling restrained braced frame (RBRBF) is used. RBRBF system generates uniform story drifts over the height of structure and prevents the damage concentration in one or few stories. Unlike conventional braced frames, the braces on one side of the braced span along with the adjacent columns and ties are part of a vertical truss system that is hinged at the base and designed to remain elastic until the near collapse limit state is reached. This vertical truss system works as a strong support for preventing damage concentration in one or few stories of the braced frame. The braces on the other side of the braced span are BRBs and are designed to provide energy dissipation. The novelty of this paper is investigating the seismic collapse of this new structural system under the effect of subduction ground motion records, which have higher significant duration compared with crustal ground motion records. For this purpose, the considered structures are assumed to be located in Seattle, which is subjected to both subduction and crustal ground motions. The results indicate that RBRBFs can effectively reduce drift concentration using the displacement‐based design approach and under both crustal and subduction ground motion records have significantly better performance in terms of seismic collapse compared with BRBFs. In addition, all structures under subduction records have lower collapse capacity values compared with crustal records.

کلیدواژه‌ها [English]

  • Crustal and subduction ground motion records
  • Seismic collapse
  • Relative lateral displacement
  • Rocking buckling restrained braced frame
  • Incremental dynamic analysis
[1] Bosco, M., Marino, E. M. and Rossi, P. P. (2018). A design procedure for pin‐supported rocking buckling‐restrained braced frames. Earthquake Engineering & Structural Dynamics, vol. 47, no. 14, pp. 2840-2863.
[2] Feng, Y., Zhang, Z., Chong, X., Wu, J. and Meng, S. (2018). Elastic displacement spectrum-based design of damage-controlling BRBFs with rocking walls. Journal of Constructional Steel Research, vol. 148, pp. 691-706.
[3] Black, C., Makris, N. and Aiken, I. (2002). Component testing, stability analysis and characterization of buckling restrained braces. Berkeley: Pacific Earthquake Engineering Research Center, University of California. [Accessed 08. 2018].
[4] Uriz, P. and Mahin, S. (2008). Toward earthquake-resistant design of concentrically braced steel-frame structures. Berkeley: Pacific Earthquake Engineering Research Center, University of California. [Accessed 05. 2019].
[5] Kumar, G. R., Kumar, S. S. and Kalyanaraman, V. (2007). Behaviour of frames with non-buckling bracings under earthquake loading. Journal of constructional steel research, vol. 63, no. 2, pp. 254-262.
[6] Asgarian, B. and Amirhesari, N. (2008). A comparison of dynamic nonlinear behavior of ordinary and buckling restrained braced frames subjected to strong ground motion. The Structural Design of Tall and Special Buildings, vol. 17, no. 7, pp. 367-386.
[7] Lai, J. W. and Mahin, S. A. (2015). Strongback system: A way to reduce damage concentration in steel-braced frames. Journal of Structural Engineering, vol. 141, no. 9.
[8] Tremblay, R. and Poncet, L. (2005). Seismic performance of concentrically braced steel frames in multistory buildings with mass irregularity. Journal of Structural Engineering, vol. 131, no. 9, pp. 1363-1375.‏
[9] Khatib, I. F., Mahin, S. A. and Pister, K. S. (1988). Seismic behavior of concentrically braced steel frames. Berkeley, CA, USA, UCB/EERC‐88/01: Earthquake Engineering Research Center, University of California.‏ [Accessed 08. 2018].
[10] Bosco, M. and Rossi, P. P. (2009). Seismic behaviour of eccentrically braced frames. Engineering Structures, vol. 31, no. 3, p.p. 664-674.‏
[11] Rossi, P. P. (2007). A design procedure for tied braced frames. Earthquake engineering & structural dynamics, vol. 36, no. 14, p.p. 2227-2248.‏
[12] Tremblay, R. and Merzouq, S. (2005). Assessment of Seismic Design forces in Dual Buckling Restrained Braced Steel Frames. In Proc. First International Workshop on Advances in Steel Constructions, Ischia, Italy, pp. 739-746.‏
[13] Foschaar, J. C., Baker, J. W. and Deierlein, G. G. (2012). Preliminary assessment of ground motion duration effects on structural collapse. In: 15th World Conference on Earthquake Engineering. Lisbon: National Information Centre of Earthquake Engineering.
[14] Chandramohan, R., Baker, J. W. and Deierlein, G. G. (2016). Quantifying the influence of ground motion duration on structural collapse capacity using spectrally equivalent records. Earthquake Spectra, vol. 32, no. 2, pp. 927-950.
[15] CSI (2016). Computer program ETABS Ultimate 2015. Berkeley: Computers and Structures Inc.
[16] ASCE/SEI 7-10 (2010). Minimum design loads for buildings and other structures. Reston: American Society of Civil Engineers.
[17] Eurocode 8 (2003). Design of structures for earthquake resistance-part 1: general rules, seismic actions and rules for buildings. Brussels: European Committee for Standardization.‏
[18] ANSI/AISC 360-10 (2010). Specification for structural steel buildings. Chicago: American Institute of Steel Construction.
[19] ANSI/AISC 341-10 (2010). Seismic provisions for structural steel buildings. Chicago: American Institute of Steel Construction.
[20] GCR 10-917-8 (2010). Evaluation of the FEMA P-695 methodology for quantification of building seismic performance factors. Gaithersburg: National Institute of Standards and Technology (NIST). [Accessed 08. 2018].
[21] Krawinkler, H. (2000). State of the art report on systems performance of steel moment frames subject to earthquake ground shaking. Federal Emergency Management Agency, Report no. FEMA-355C, SAC Joint Venture.‏
[22] McKenna, F., Fenves, G. L. and Scott, M. H. (2015). Open system for earthquake engineering simulation. Berkeley: Pacific Earthquake Engineering Research Center.
[23] Asgarkhani, N., Yakhchalian, M. and Mohebi, B. (2020). Evaluation of approximate methods for estimating residual drift demands in BRBFs. Engineering Structures, Vol. 224.‏
[24] Barbosa, A. R., Ribeiro, F. L. and Neves, L. A. (2017). Influence of earthquake ground‐motion duration on damage estimation: application to steel moment resisting frames. Earthquake Engineering & Structural Dynamics, vol. 46, no. 1, pp. 27-49.
[25] Gray, M. G. (2012). Cast steel yielding brace system for concentrically braced frames. Ph.D. Dissertation. University of Toronto.
[26] Guerrero, H., Tianjian, Ji., Teran-Gilmore, A. and Alberto Escobar, J. (2016). A method for preliminary seismic design and assessment of low-rise structures protected with Buckling-Restrained Braces. Engineering Structures, Vol. 123, pp. 141-154.
[27] Sabelli, R. (2001). Research on improving the design and analysis of earthquake-resistant steel-braced frames. Oakland, CA, USA: EERI.‏ pp. 1-142.
[28] Raghunandan, M., Liel, A. B. and Luco, N. (2015). Collapse risk of buildings in the Pacific northwest region due to subduction earthquakes. Earthquake Spectra, vol. 31, no. 4, pp. 2087-2115.
[29] U.S. Geological Survey, (2021). https://earthquake.usgs.gov/hazards/interactive/. [Accessed 01. 05. 2021].
[30] Eads, L. (2013). Seismic collapse risk assessment of buildings: effects of intensity measure selection and computational approach. Stanford University.
[31] Soltani, M. H., Yakhchalian, M., Tavakoli, M. and Mirzaei, M. Probabilistic seismic performance assessment of rocking buckling restrained braced frames. Submitted to Journal of Building Engineering.  
[32] Champion, C. and Liel, A. (2012). The effect of near‐fault directivity on building seismic collapse risk. Earthquake Engineering & Structural Dynamics, Vol. 41, no. 10, pp. 1391-1409.‏