ارزیابی و مقایسه عملکرد مهاربندهای واگرا و همگرا در مقاوم‌سازی قاب‌های خمشی بتن آرمه

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشکده مهندسی عمران، دانشگاه سمنان

2 دانشیار، دانشکده عمران،دانشگاه سمنان

3 استاد، دانشکده مهندسی عمران، دانشگاه سمنان، سمنان، ایران

چکیده

استفاده از مهاربند فولادی یکی از روش‌های مقاوم‌سازی قاب‌ خمشی بتن‌آرمه در برابر بارجانبی است. هدف از این مقاله ارزیابی روش‌ جدید مقاوم‌سازی قاب بتنی با قاب فولادی دارای مهاربند واگرا و تیرپیوند تعویض‌پذیر، و تعبیه آن با کلاف فولادی در دهانه‌هایی از قاب بتنی است. از مزایای این روش اجرای آسان، صرفه اقتصادی و شکل‌پذیری مناسب، به دلیل وجود فیوز شکل‌پذیر در بخش الحاقی است. لذا ضمن معرفی این روش، عملکرد آن با روش‌های‌ متداول مقاوم‌سازی قاب بتنی با مهاربند همگرا مقایسه شده است. در این مقاله 6 روش مقاوم‌سازی قاب بتنی، شامل مهاربند ضربدری، مهاربند به شکل8، مهاربند واگرا با تیر پیوند بتنی، مهاربند واگرا با تیر پیوند فولادی، متصل به دو ستون فولادی در کلاف، مهاربند واگرا و تیر پیوند فولادی متصل به کلاف، با دو ستون فولادی بین کلاف و تیر فولادی، و مهاربند واگرا و تیر پیوند فولادی متصل به کلاف مورد مطالعه قرار گرفته است. همه مدل‌ها دارای کلاف فولادی محاط کننده‌ی مهاربند و متصل به قاب بتنی است. نتایج تحلیل دینامیکی خطی در همه قاب‌های‌ مقاوم‌سازی شده، کاهش تغییرمکان جانبی نسبی و کاهش نسبت نیرو به ظرفیت در اعضای قاب بتنی، نسبت به قاب‌ بتنی بدون تقویت را نشان داده است. در روش‌های جدید مقاوم‌سازی قاب بتنی با مهاربند واگرا و تیرپیوند فولادی کاهش میزان مصرف فولاد تا 38 درصد و کاهش برش‌پایه تا 18درصد نسبت به روش مقاوم‌سازی قاب‌بتنی با مهاربند همگرای ضربدری مشاهده شده است. تحلیل استاتیکی غیرخطی و دینامیکی غیرخطی مدل‌ها با نرم افزار PERFORM-3D انجام شده است. از بررسی رفتار غیرخطی مدل‌ها، مدل مهاربند واگرا و تیر پیوند فولادی متصل به کلاف از سختی، شکل پذیری، ضریب رفتار و قابلیت استهلاک انرژی بیشتری نسبت به سایر مدل‌ها برخوردار بوده است و تشکیل اولین مفصل پلاستیک در تیرپیوند این مدل، بیان‌گر عملکرد مناسب تیرپیوند به عنوان فیوزسازه‌ای است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation and Comparison of Divergent and Convergent Bracing Performance in Strengthening of Reinforced Concrete Frames

نویسندگان [English]

  • ROBABEH OMRANI 1
  • Mohammad Ali Kafi 2
  • Ali Kheyroddin 3
1 semnan university
2 Faculty of Civil Engineering., Semnan University, Semnan, Iran
3 Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
چکیده [English]

The steel bracing system is one of the appropriate methods for the strengthening of concrete moment frames against lateral forces. The article purpose is the evaluation of the new strengthening method of reinforced concrete moment frame with convergent bracing and interchangeable link beams that is embedded in the steel frame and installed in the concrete frame spans. This new method is easy to execute, economical and ductile with appropriate performance because of the existence of ductile fuse in its accession section. Therefore, this method is introduced and compared to other strengthening methods by steel bracing. In this article six concrete frame strengthening methods investigated include x-convergent bracing, reverse chevron bracing, divergent bracing with concrete link beam, divergent bracing with steel link beam connected to steel columns in the steel frame, divergent bracing with steel link beam connected to the steel frame with steel columns between those two, divergent bracing with steel link beam connected to the steel frame. All strengthening models attached to concrete frames by a steel frame surrounding them. The linear dynamic analysis results showed a decrease in relative lateral displacement and stress ratio of concrete frame members in all strengthed frames compared to the nonstrengthed frame. Also in the strengthed frame by divergent bracing and steel link beam, the results revealed a 38% steel consumption decrease and an 18% base shear decrease compared to strengthed frame by x-convergent bracing. Nonlinear static and dynamic analysis of models were done by PERFORM-3D software. The nonlinear behavior results of the strengthed concrete frame by divergent bracing with steel link beam connected to the steel frame showed more stiffness, ductility, behavior coefficient and energy dissipation than other models. Also, in this model, an appropriate performance of the structural fuse was shown by the plastic hinge formation of the link beam.

کلیدواژه‌ها [English]

  • strengthening
  • Concrete Moment Frame
  • Convergent Bracing
  • Divergent Bracing
  • Structural Fuse
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