محاسبه عوامل مؤثر بر ضریب رفتار قاب های بتن مسلح دارای مهاربند کمانش تاب

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد، دانشکده مهندسی عمران و محیط زیست، دانشگاه تربیت مدرس

2 استاد، دانشکده مهندسی عمران و محیط زیست، دانشگاه تربیت مدرس

چکیده

امروزه استفاده از مهاربندهای کمانش تاب به دلیل داشتن مزایای بیشتر در مقایسه با مهاربندهای فولادی متداول، مورد توجه محققان و مهندسان قرار گرفته است. این مزایا عبارتند از: شکل پذیری بالا، استهلاک انرژی بیشتر، عدم کمانش کلی و موضعی و همچنین داشتن منحنی چرخه ای متقارن. این نوع مهاربندی به عنوان یکی از سامانه های مؤثر برای مقابله با بارهای
جانبی ناشی از زلزله به شمار می رود. معایب موجود در رفتار لرزه ای مهاربندهای معمولی همچون شکل پذیری و اتلاف انرژی کم، کمانش کلی و موضعی و همچنین داشتن منحنی چرخه ای نامتقارن، زمینه اصلاح یا کنار گذاشتن آن را از فرایند طراحی لرزه ای فراهم آورده است. مهاربندهای کمانش تاب نوعی از سامانه مستهلک کننده انرژی هستند که علاوه بر تأمین سختی جانبی زیاد، شکل پذیری و میزان استهلاک انرژی سازه را افزایش می دهند. استفاده از این نوع مهاربندها در آئین نامه های برخی از کشورها مجاز شمرده می شود. اما در برخی دیگر و از آن جمله ایران، اشاره ای به آن نشده است. این مقاله سعی دارد تا عوامل شکل پذیری و لرزه ای آن ها را مورد تحقیق و بررسی قرار دهد. در این تحقیق، ضریب رفتار قاب های بتن مسلح دارای مهاربند کمانش تاب با تعداد طبقات چهار، هشت، دوازده و شانزده که هر یک دارای تعداد دهانه سه و پنج هستند، مطابق با مبحث نهم مقررات ملی
ساختمان طراحی شده و سپس با استفاده از نرم افزار OPENSEES تحت بارگذاری استاتیکی غیرخطی قرارگرفته و ضریب رفتار کلیه قاب ها برای حالت حدی نهایی محاسبه شده است.

کلیدواژه‌ها

عنوان مقاله [English]

Determination of the Parameters Influencing Behavior Factor of Buckling Restrained Braced Reinforced Concrete Frames

نویسندگان [English]

  • F. Dehghan 1
  • A. A. Tasnimi 2
1 M.Sc., Facaulty of Civil and Environmental Engineering, Tarbiat Modares University
2 Professor, Facaulty of Civil and Environmental Engineering, Tarbiat Modares University
چکیده [English]

The advantages of buckling restrained braces (BRB) attract the researches and engineers attention
to use this bracing system. High ductility, high-energy dissipation capacity and symmetric hysteresis
behavior are the main advantages of this system that is the most effective system to resist the earthquake
induced lateral forces. Disadvantages of conventional bracing system such as low ductility, low energy
dissipating capacity and local as well as global buckling with unsymmetrical hysteresis performance
in tension and compression are the main reason to rehabilitate and or replace this system with the new
generation of braces. Buckling restrained brace (BRB) is an energy-dissipating member that enhances
the structural stiffness, energy dissipation and ductility. There are few worldwide code of practices
provide some recommendations about the buckling-restrained braced frames whereas most of them do
not deal with such system. This paper illustrates the good performance of buckling restrained braces
used for RC frames. This article determines the behavior factor for RC frames braced with buckling
restrained braces. For this purpose RC frames with four, eight, twelve and sixteen stories (each having
three and five bays) were considered in this study. All frames designed in accordance with Iranian
standard 2800 and P9-INBC for concrete structures. Analyses for all 24 structural models were carried
out utilizing nonlinear static push‑over method. The results indicate that the average value of behavior
factor for all models corresponding to the allowable stress design is around eight.

کلیدواژه‌ها [English]

  • Buckling Restrained Brace
  • Ductility
  • energy dissipation
  • Nonlinear Analysis
  • behavior factor

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 48، شماره 4
دی 1395
صفحه 365-374

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