تاثیر میزان صلبیت اتصالات بر احتمال آسیب‌پذیری قابهای خمشی فولادی

نوع مقاله: علمی - پژوهشی

نویسندگان

1 دانشیار، دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

2 دانشجوی دکتری مهندسی عمران، دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

چکیده

در فرآیند تحلیل قابهای خمشی فولادی ، اتصالات به دو دسته مفصلی ایده­آل و صلب ایده­آل، معادلسازی میشوند. این ایده­آلسازی اگرچه تاحد بسیار زیادی روند تحلیل را ساده مینماید، ولی موجب کم­توجهی به رفتار واقعی اتصال میگردد. تحقیقات نشان داده است وقتی رفتار اتصالات با رفتار صلب کامل ایده­آلسازی میگردد این معادلسازی موجب کاهش ایمنی قابها میگردد، چراکه با این فرض دریفتهای واقعی طبقات کم پیش­بینی شده و احتمالا قاب بی­نیاز از طرح مهاربند برآورد میگردد. در این تحقیق برای بررسی تاثیر ایده­آلسازی رفتار اتصالات بر احتمال خرابی قابها، یک قاب یک دهانه چهار طبقه با سه تیپ اتصال با صلبیت های 10، 75 و90 درصد مدل شده و با مبنا قرار دادن دریفت حداکثر در بام با توجه به حداکثر های مختلف شتاب حرکت زمین، احتمال خرابی کم، متوسط، زیاد و کامل محاسبه شد. درنهایت برررسی ها نشان دادند که هرچه اتصال در قاب به سمت صلبیت بالاتر سوق داده شود این مهم موجب کاهش احتمال خرابی قابها در برآورد احتمال شکست میگردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Connections rigidity effect on probability of fracture in steel moment frames

نویسندگان [English]

  • Gholamreza Abdollahzadeh 1
  • Ehsan Shabanzadeh 2
1 Associate Professor, Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran
2 PhD Student, Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran
چکیده [English]

Connections in steel moment frames are idealized in full pinned and full rigid conditions. Because with this assumption, in spite of real behavior of connection, real story drifts are less anticipated and maybe frame is designed without performance of bracing. There are several methods for modeling actual behavior of semi rigid connections. In this method a connection with certain rigidity is modeled by a rotational spring with corresponding stiffness. This stiffness is achieved by certain formula. In other words, each percent of rigidity corresponds to one rotational spring stiffness. In this research in order to evaluate the real behavior of connection in analysis and designing process and fracture probability one frame including four stories and one bay with three types of connection has been modeled and designed in ETABS. Each model has an individual rigidity which is equal to 10, 75 and 90 percent. With respect to maximum drift and different PGA in roof, probabilities of low, medium, high and complete fracture were calculated. For this purpose, with applying different PGA to modeled frames, amounts of drift in the roof are achieved. Then these values are compared with given values in American code. Finally, investigation showed that when rigidity in frame connections increases, the probability of frame fracture decreases. In other words, fully rigid assumption of connection in analysis process leads to decreasing in real probability of fracture in frames which is a noticeable risk in building designing processes.

کلیدواژه‌ها [English]

  • Steel moment frame
  • Connection rigidity
  • drift
  • PGA
  • Failure probability

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