پیشنهاد سیستم مهاربندی نوین با پره‌های دایروی خمشی جاری شونده تحت بار چرخه‌ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 عضو هیات علمی رسمی قطعی

2 گروه سازه- دانشکده عمران-دانشگاه صنعتی خواجه نصیرالدین طوسی-تهران- ایران

چکیده

استفاده از سیستم‌های مهاربندی معمول چون مهاربندهای هم مرکز در سازه‌های فولادی، پرکاربردترین روش برای مقابله با بارهای جانبی است. یکی از اشکالات این سیستم‌ها، کمانش در هنگام اثر بار فشاری است که موجب می‌گردد مهاربند قبل از رسیدن به حد تسلیم دچار ناپایداری شود. به عبارتی رفتار این مهاربندها در کشش و فشار نامتقارن بوده و علاوه بر کاهش توان سیستم در جذب انرژی تحریک سیستم، ساختمان­های دارای این مهاربندها تحت ضربه حاصل از تغییر جهت نیروهای اینرسی قرارگرفته و لذا صدمات زیادی به اجزای سازه­ای و غیرسازه­ای آن‌ها وارد می­گردد. جهت حل این مشکل در راستای بهبود عملکرد مهاربندها، در این مقاله سیستم مهاربندی نوینی با عنوان مهاربند پره‌ای برای اولین بار معرفی شده است. مهاربند پره‌ای با کمک حذف اثرات مضر کمانش فشاری، خاصیت شکل‌پذیری و جذب انرژی سیستم را از طریق جایگزینی تغییرشکل‌های محوری توسط تغییرشکل­های خمشی، بهبود می­بخشد. این جایگزینی سبب نرم‌تر شدن سیستم و به تبع آن افزایش پریود ارتعاش طبیعی سیستم و لذا کاهش برش پایه زلزله می‌گردد. در این تحقیق با مدل‌سازی عددی و اعمال بارگذاری چرخه‌ای براساس پروتکل بارگذاری ATC-24، مهاربند پیشنهادی مورد مطالعه قرار می­گیرد. رفتار متقارن حتی تحت جابه‎جایی‌های چرخه‌ای بزرگ و همچنین جذب انرژی بالا و وزن کمتر در مقایسه با مهاربند‌های رقیب آن چون مهاربند کمانش تاب از مزایای این سیستم می‌باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Proposing a New Bracing System with Bending Yielding Circular Plates under Cyclic Loading

نویسندگان [English]

  • Seyed bahram Beheshti Aval 1
  • Saba Ghayoumi 2
2 K.N. Toosi University of Technology, Tehran, Iran.
چکیده [English]

The most prevalent way to deal with lateral loads in steel structures is using common bracing systems like concentric bracing systems. One of the major drawbacks of this system is the buckling when the compression force exceeds the elastic buckling strength, thereby being unstable before reaching the yield limit. In other words, the behavior of these braces is asymmetric under tension/compression forces leading to reduce the ability of the system to absorption of the most exciting energy and can lead to additional structural and non-structural damages due to the change in the direction of the inertial forces. To tackle these problems and to improve the performance of bracing systems, in this work for the first time, a new bracing system called a fan bracing system has been introduced. Fan brace enhances the ductility and energy absorption of the system by removing harmful buckling effects byreplacing axial deformations with flexural ones, which tends to make the system softer and thus increase the natural vibration period of the structure and reduce the earthquake shear force. In this study, the proposed brace is studied using numerical modeling under affecting cyclic excitation based on the loading protocol of ATC-24. The advantages of this system include the symmetrical behavior even in the large cyclic deformations, as well as high energy absorption and lighter weight in comparison with the buckling-restrained brace (BRB).

کلیدواژه‌ها [English]

  • fan bracing system
  • Numerical modeling
  • Cyclic loading
  • Energy Absorption
  • seismic loading
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