ارزیابی کفایت تحلیل طیفی برای تحلیل لرزه‌ای ساختمآن‌های فولادی دارای سیستم قاب خمشی و قاب مهاربندی همگرا مطابق آیین‌نامه‌های زلزله معتبر

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی سهند، تبریز، ایران

چکیده

در تحلیل لرزه‌ای ساختمآن‌های با ارتفاع زیاد، مطابق آیین‌نامه‌های زلزله، روش تحلیل طیفی به خاطر قابلیت در نظرگیری اثر مودهای ارتعاشی بالاتر استفاده می‌شود. از طرف دیگر، تحلیل تاریخچه زمانی غیرخطی، قدرتمندترین روش جهت برآورد پاسخ­های لرزه­ای ساختمآن‌ها می­باشد. لذا در این تحقیق، دقت و کفایت روش تحلیل طیفی، با مقایسه نتایج پاسخ­ های لرزه­ ای حاصل از آن با روش دقیق تاریخچه زمانی غیرخطی مورد بررسی قرار می­ گیرد. برای این منظور، 6 سازه فولادی سه بعدی با تعداد طبقات 4، 10 و20 با سیستم ­های قاب خمشی ویژه و قاب مهاربندی همگرای ویژه در نظر گرفته شده‌اند. برای انجام تحلیل­ های تاریخچه زمانی غیرخطی و طیفی، 4 گروه 7 تایی شامل شتاب‌نگاشت نزدیک گسل با ویژگی­ های جهت‌پذیری پیش رونده، اثر پرتابی و بدون پالس و همچنین شتاب‌نگاشت‌های دور از گسل استفاده شده است. نتایج نشان می ­دهند که در اکثر سازه ­ها پاسخ­های لرزه­ای حاصل از تحلیل طیفی نسبت به تحلیل تاریخچه زمانی غیرخطی دارای مقادیر دست پایین و غیرمحافظه کارانه می­ باشند و معمولا میزان خطای روش تحلیل طیفی با افزایش ارتفاع سازه بیشتر می‌شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of the adequacy of the response spectrum analysis for the seismic analysis of moment-resisting and concentrically-braced buildings according to the seismic design codes

نویسندگان [English]

  • ahmadreza fatahi
  • Mehdi Poursha
sahand university
چکیده [English]

According to the seismic design codes, the response spectrum analysis (RSA) method can be used for the seismic analysis of tall buildings since it can consider the effect of higher modes. In addition, the nonlinear time history analysis is the most accurate method of evaluating the seismic responses of structures. Consequently, the present study investigates the accuracy of the RSA method by comparing the seismic responses computed by the RSA with the nonlinear time history analysis. To this end, six 3D structures with 4-, 10- and 20-story heights are investigated in this paper. The lateral load-resisting systems of the structures include special steel moment-resisting frames (MRFs) and concentrically braced frames (CBFs). To conduct the nonlinear time history analyses, four sets of ground motion records including three groups of near-fault records with different characteristics and one set of far-fault records are used. The near-fault ground motion sets include forward directivity, fling step and no pulse characteristics. All sets comprise seven seismic ground motion records. The results indicate that the seismic responses obtained by the RSA, are mostly underestimated and non-conservative in comparison with those from the nonlinear time history analysis. In general, the more the height of the structure, the larger the error in the seismic responses derived from the RSA. Also, the largest error in the RSA relative to the rigorous time history analysis occurs in the case of the near-fault ground motions with the fling-step effect.

کلیدواژه‌ها [English]

  • Response spectrum analysis
  • Nonlinear time-history analysis
  • Near-fault ground motions
  • Far-fault ground motions
  • Moment-resisting frame
  • Concentrically-braced frame
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