مطالعه پارامتری رفتار خمش خارج از صفحه اتصالات لوله‌ایT شکل فولادی تحت آتش استاندارد

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران

2 دانشکده مهندسی عمران، دانشگاه آزاد اسلامی واحد پرند، ایران

چکیده

مقاله حاضر به بررسی رفتار اتصالات T شکل دایره‌ای توخالی لوله‌ای فولادی تحت بار توأمان آتش و خمش خارج از صفحه می‌پردازد. نویسندگان اولین مطالعه تجربی آزمایشگاهی را بر روی رفتار در دمای بالای اتصالات T شکل لوله­ای فولادی ساده تحت لنگر خمشی خارج صفحه انجام دادند. در ابتدا خلاصه نتایج یک مطالعه آزمایشگاهی انجام‌ شده بر روی سه نمونه اتصال T شکل فولادی گزارش می‌شود. یک نمونه در دمای محیط تحت خمش خارج از صفحه شبه‌استاتیکی افزایشی وارده به مهار و دو نمونه دیگر تحت خمش خارج از صفحه و آتش استاندارد ISO-834 مورد آزمایش قرار گرفتند. در ادامه به‌ منظور بررسی تفصیلی اتصالات مذکور، رفتار خمش خارج از صفحه آن‌ها به کمک تحلیل اجزای محدود مکانیکی - حرارتی تحت آتش استاندارد شبیه‌سازی شد. پس از صحت­سنجی مدل عددی از طریق مقایسه نتایج آن با نتایج مطالعات آزمایشگاهی، به منظور بررسی تأثیر پارامترهای هندسی و نرخ بارگذاری بر روی رفتار اتصالات، یک سری مطالعات پارامتری بر روی اتصالات T شکل در مقیاس کامل انجام شد. نتایج این مطالعات نشان داد که ‌نرخ بار اعمالی به مهار و پارامتر هندسی نسبت قطر مهار به پایه، تأثیر پراهمیت‌تری نسبت به سایر پارامترهای هندسی بر روی رفتار اتصال تحت آتش داشته است. افزایش نسبت قطر مهار به پایه از0/2 به 1، باعث کاهش 56 درصدی دوران پسماند اتصال و افزایش 23 درصدی دمای بحرانی اتصال گردید. با افزایش نرخ بار اعمالی به مهار از 0/2 به 1 نیز دوران پسماند 245 درصد افزایش و دمای بحرانی 37 درصد کاهش یافت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A parametric study on OPB fire response of steel CHS T-joints

نویسندگان [English]

  • Farid Ahmadpour 1
  • Mostafa zeinedini 1
  • Mohammad Motamedi 2
  • Reza Rashnooie 1
  • S.Amin Hosseini 1
1 Ph.D student, Civil Engineering Department, K.N.Toosi University of Technology, Tehran, Iran
2 Department of Civil Engineering, Parand Branch, Islamic Azad University, Parand, Iran
چکیده [English]

The behavior of steel circular hollow section (CHS) T-joints under combined fire load and out-of-plane bending (OPB) is investigated. A review of the literature indicates that the subject has not been previously considered by researchers. The authors carried out the first laboratory experimental study on OPB behavior of simple steel tubular T-joints under standard fire. The results of an experimental and numerical study performed on three small-scale steel tubular T-joint specimens are reported. One specimen was tested at ambient temperature under quasi-static incremental OPB moment in the brace and the other two specimens were tested under OPB moment plus exposure to ISO-834 standard fire. In order to have a deeper insight into the strength and failure mechanism of steel tubular T-joints under fire, their OPB behavior was also studied using coupled mechanical-thermal finite element modeling. The numerical model was validated against the experimental results and reasonable agreements were achieved. A parametric study was then performed on the OPB fire behavior of full-scale steel tubular T-joints. The results showed that the superimposed OPB ratio in the brace and the diameter ratio parameter had more pronounced effects on the fire response of the joint as compared to other geometric and loading parameters. Increasing the diameter ratio parameter from 0.2 to 1, reduced the joints residual rotation by 56 % and increased the critical temperature by 23 %. By increasing the OPB ratio from 0.2 to 1, the residual rotation increased by 245 % and the critical temperature decreased by 37%.

کلیدواژه‌ها [English]

  • Steel tubular T-joint
  • Out of Plane Bending (OPB)
  • Thermal - stress analysis
  • Failure mode
  • Critical temperature
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