رفتار لرزه‌ای اتصالات بتن‌آرمه تقویت شده با FRP با اعمال اثر چسبندگی فصل مشترک بتن-FRP

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده فنی و مهندسی، دانشگاه خوارزمی، تهران، ایران

چکیده

در این پژوهش با استفاده از روش اجزای محدود غیرخطی، مطالعه عددی روی رفتار اتصالات بتن­ آرمه تحت بارگذاری جانبی انجام می‌گیرد. این اتصالات بر پایه آیین‌نامه‌های قدیمی و بدون ملاحظه ضوابط و جزییات لرزه ­ای حاضر در آیین‌نامه‌های جدید، طراحی شده و­ از تکنیک استفاده از ورق­ های FRP با اتصال خارجی برای تقویت آن‌ها استفاده گردیده است. در مدل­ المان محدود پیشنهادی، علاوه بر اعمال مشخصه ­های رفتار غیرخطی بتن در فاز کشش و فشار، مکانیزه ای خرابی ورق ­های FRP و عملکرد چسبندگی و جدایش در ناحیه فصل مشترک بتن-FRP نیز شبیه­ سازی شده است. دقت مدل پیشنهادی با مقایسه نتایج عددی به‌ صورت نمودار پوش حاصل از تحلیل سیکلی با داده ­های شش نمونه آزمایشگاهی پیشین صحت­ سنجی شد. مشاهده می­ شود که منحنی‌های پوش حاصل از این مدل‌سازی با دقت خوبی مقاومت و تغییر شکل ماکزیمم نمونه‌ها را پیش‌بینی می‌نماید. در ادامه مطالعه بر پایه مدل صحت­ سنجی شده، رفتار دو ­بعدی اتصالات خارجی، عملکرد سه ‌بعدی اتصالات داخلی و خارجی با در نظر گرفتن اثر دال و تیر جانبی و همچنین تقویت اتصالات به ‌صورت سه­ بعدی و کاربردی، با استفاده از ورق­ های FRP و با تمرکز بر نقش ناحیه فصل مشترک، مورد ارزیابی قرار می­ گیرد. دیده می ­شود که دال و تیر عرضی در عملکرد اتصالات معیوب نقش مهمی دارد که می ­تواند تا بیش از 20 درصد مقاومت نمونه را افزایش دهد؛ همچنین در مدل­ های تقویت سه­ بعدی اتصالات، احتمال وقوع جدایش ورق FRP از حالت دو بعدی بیشتر است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Seismic performance of FRP-strengthened RC joints by applying bond effects of concrete-FRP interface

نویسندگان [English]

  • Gholamreza Nouri
  • Morteza Kamalvand
Faculty of Engineering, Kharazmi University, Tehran , Iran
چکیده [English]

In this research, using the nonlinear finite element method, a numerical study has been performed on the seismic behavior of the deficient RC beam-column joints (with non-seismic detailing), and the seismic rehabilitation of these joints by using FRP composite laminates. At first, based on previous experimental studies, a series of RC joint specimens were considered to verify the proposed numerical model. This series of specimens include six RC interior joint specimens with non-seismic detailing and retrofitted with FRP laminates under cyclic loading. Comparison between the load-displacement curves obtained from the numerical model with corresponding experimental data shows that the proposed model is capable to high accurately predict the response of RC joints under cyclic loading. Then, based on the verified model, the performance of two-dimensional (2-D) deficient and strengthened exterior RC joint, three-dimensional (3-D) interior and exterior RC joints with considering the effect of the slab and beam perpendicular to the plane of the frame and also strengthening of (3-D) RC joints with focusing on the behavior of the FRP to the concrete interface is evaluated. It was observed that the failure mode of the retrofitted RC exterior specimens, unlike the deficient specimens, is the formation of the plastic hinge in the beam section. In addition, it is seen that the slab and the lateral beam have a significant effect on the performance of deficient joints, which can increase the resistance of the 3-D specimens by more than 20%; also, in 3D strengthened joints, the possibility of debonding of FRP laminates from concrete is higher than the 2-D model.

کلیدواژه‌ها [English]

  • RC beam-column joints
  • Nonlinear finite element
  • FRP laminate
  • Cyclic loading
  • Bond effects FRP-Concrete interface

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نشریه مهندسی عمران امیرکبیر
دوره 54، شماره 9
آذر 1401
صفحه 3263-3286

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