دو شیوه‎ی یافتن برش پایه‎ برای طرح خمیری قاب ها

نوع مقاله : علمی - پژوهشی

نویسندگان

1 مشهد- دانشگاه فردوسی مشهد- دانشکده ی مهندسی گروه عمران

2 کارشناسی ارشد، دانشگاه فردوسی، مشهد، ایران

چکیده

روش طرح خمیری (پلاستیک) برپایه‎ی عملکرد، با هدف دستیابی به پاسخ بهتر برای ساختمان‎ها در زیر اثر زمین‎لرزه‎های شدید، گسترش فراوانی پیدا کرده است. برای انجام این کار، فن های گوناگونی تاکنون پیشنهاد نموده اند. در این پژوهش، شیوه‎‎ی دستیابی به برش پایه در راه‎کار طرح خمیری برپایه‎ی عملکرد بررسی می‎گردد. برای رسیدن به این هدف، دو فرآیند محاسبه‎ی برش پایه به کار می‎رود و از پاسخ‎های این دوفن درطرح سازه ها بهره جویی می‎شود. برش پایه‎ی دو قاب‎ خمشی سه طبقه و شش طبقه به دو گونه‎ی طیف نقطه‎ی تسلیم و کارمایه( انرژی) حساب خواهد شد. سپس، از اختلاف بین کارمایه ی‎ وارد به سازه و کارمایه ی کرنشی کشسان آن، مقدار جذبی به دست می‎آید. با بهره جستن از این کارمایه ی خمیری، طرح عضوهایی انجام می‎پذیرد، که نامزد تسلیم هستند و در ادامه ، با به کار بردن نیروهای ناشی از خمیری شدن عضوهای شکل‎پذیر و شرط ایستایی درخت ستون، ظرفیت ستون‎ها در دسترس قرار می‎گیرد. سرانجام، از تحلیل‎های ناخطی ایستا و پویا (دینامیکی) بهره جویی خواهد شد و عملکرد این قاب‎ها ارزیابی می‎شود. این پژوهش، به مقایسه ی این دو راه کار می‌پردازد و نتیجه ها نشان می دهند که در ساختمان‎های متوسط و بلند، بهره جستن از معادله‎ی کارمایه برای حساب کردن برش پایه‎، طرح را مناسبتر می‌سازد. هرچند، نمودار پخش تغییرمکان نسبی در ارتفاع برای قاب های طرح شده به شیوه‌‌‌ی طیف نقطه‌ی تسلیم، قابل پیش بینی تر است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Two techniques for calculating design base shear

نویسندگان [English]

  • Mohammad Rezaiee-Pajand 1
  • Elham Mirafzali 2
1 Civil Eng., Ferdowsi University of Mashhad, Iran
2 Department of civil engineering, Ferdowsi university of Mashhad, Mashhad, Iran
چکیده [English]

Performance-Based Plastic Design (PBPD) method has been recently developed to achieve the enhanced response of structures to earthquake. To reach this goal, several ways have been suggested. In this paper, the schemes of calculating base shear in the (PBPD) procedure will be studied. Two techniques of determining base shear will be used. The base shear of two steel moment frames will be found by these two processes. By using the difference between the input energy and the elastic strain energy to obtain the plastic energy, the plastic design is then performed to detail the frame members in order to achieve the intended yield mechanism and behavior. The inelastic seismic behaviors of the four frames were studied through nonlinear static and dynamic analyses. These two suggested techniques and their comparisons have not been proposed yet. This kind of plastic design has three main parts. Calculating base shear is the first and important portion. The second part consists of the member plastic design for flexible behavior. To design elastic members by using column trees is the third and last part. Throughout this study is devoted to present two methods for calculating base shear. The moment frames will be investigated in this article.

کلیدواژه‌ها [English]

  • Base Shear
  • Performance-Based Plastic Design
  • Yield Point Spectra
  • Energy
  • Target Displacement
  • Yield Mechanism

مراجع

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[2]  Goel, S. C., Lioa, W.C.,Chao S. H. and Bayat, M.R. (2010). Performance-Based Plastic Design (pbpd) Method for Earthquake Resistant Structures: An overview. The structural design of tall and special buildings. Wiley Interscience , Vol. (19),  pp (115137).
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سابقه مقاله

  • تاریخ دریافت: 07 اردیبهشت 1397
  • تاریخ بازنگری: 22 شهریور 1397
  • تاریخ پذیرش: 09 آذر 1397

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