ارزیابی طول موثر پیوستگی روش کاشت الیاف در نصب خارجی به روش سرعت‌سنجی تصویری ذرات

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی تحصیلات تکمیلی، گروه مهندسی عمران، دانشگاه فردوسی مشهد

2 استادیار گروه مهندسی عمران، دانشگاه فردوسی مشهد

چکیده

مقاومت پیوستگی بین ورق پلیمر مسلح با الیاف (FRP )و بتن، عامل اصلی مؤثر بر رفتار اعضای بتنی مقاوم‌سازی شده به روش نصب خارجی (EBR) می‌باشد. مقاومت پیوستگی به عوامل مختلفی همچون نوع آماده‌سازی سطحی، مقاومت بتن و ضریب کشسانی، ضخامت و طول پیوستگی ورق FRP وابسته است. براساس مطالعات پژوهشگران، افزایش طول اتصال بیشتر از طول مؤثر پیوستگی، تضمین کننده ی افزایش مقاومت پیوستگی نخواهد بود. بیشتر مدل‌های تئوری موجود، مقاومت پیوستگی را بر اساس طول مؤثر پیوستگی تخمین می‌زنند. بنابراین برای رسیدن به یک اتصال رضایت‌بخش، آگاهی از طول مؤثر پیوستگی اهمیت زیادی دارد. در این پژوهش، به منظور ارزیابی و مقایسه طول مؤثر پیوستگی در روش EBR با استفاده از کاشت الیاف و روش‌های متداول آماده‌سازی سطحی (برس‌زنی و ماسه‌پاشی)، تعداد 12 نمونه منشور بتنی ساخته شد و مورد آزمایش قرار گرفت. طول مؤثر پیوستگی و مقاومت پیوستگی نمونه‌ها با استفاده از آزمایش برش مستقیم و به کمک آنالیز میدان کرنش، به روش سرعت سنجی تصویری ذرات (PIV )به دست آمد و با مدل‌های آیین نامه‌های ایالات متحده آمریکا و اتحادیه اروپا مقایسه گردید. نتایج نشان داد که استفاده از روش کاشت الیاف به جای روش‌های آماده‌سازی سطحی متداول، موجب کاهش طول مؤثر پیوستگی به میزان 20 %و افزایش مقاومت پیوستگی به میزان 34 %می‌گردد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effective Bond Length Evaluation of Fiber Implantation Methods in EBR Applications Using Particle Image Velocimetry

نویسندگان [English]

  • Behzad Attari 1
  • Mohammadreza Tavakkolizadeh 2
1 Graduate Student, Civil Engineering Department, Ferdowsi University of Mashhad
2 َAssistant Professor of Civil Engineering, Ferdowsi University of Mashhad
چکیده [English]

The bond strength between fiber-reinforced polymer (FRP) laminates and concrete is the main factor affecting the behavior of concrete members strengthened by externally bonded reinforcement (EBR) method. The bond strength depends on several factors, such as surface preparation, concrete strength, FRP stiffness and thickness, and effective bond length. According to previous studies, using a bond length longer than the effective bond length, will not increase load-carrying capacity. Most existing theoretical models estimate bond strength based on the effective bond length. So, in order to achieve a satisfactory performance, it is important to determine the accurate value for the effective bond length of lap joints. In this study, in order to evaluate and compare the effective bond length of fiber implantation method and the conventional EBR method, 12 concrete specimens were prepared and examined. The effective bond length and the bond strength of specimens were determined using single-shear pull test and adopting particle image velocimetry (PIV) method and they were compared with the existing specifications such as ACI and fib. The results showed that using fiber implantation method instead of the conventional EBR method reduced the effective bond length by 20% and increased the bond strength between FRP and concrete substrate by 34%.

کلیدواژه‌ها [English]

  • Effective bond length
  • Fiber implantation
  • EBR
  • FRP
  • Particle Image Velocimetry (PIV)

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 52، شماره 1
فروردین 1399
صفحه 123-134

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