تاثیر مقاومت بتن و چسبندگی ورقهای CFRP انعطاف پذیر بر مقاومت نهایی تیرهای بتنی

نوع مقاله : پژوهشی

نویسندگان

• محمود نادری
• علی خونساری

دانشگاه امام خمینی (ره)

10.22067/civil.v26i2.18398

چکیده

در میان روش‌های مختلف مقاوم‌سازی استفاده از ورق‌های پلیمری مسلح به الیاف FRP با استقبال روبه‌رشدی مواجه بوده است. در استفاده از FRP، مقاومت سطحی بتن بستر تأثیر تعیین‌کننده‌ای بر مقاومت چسبندگی بین FRP و بتن دارد. لذا در این تحقیقات، مطالعه‌ی آزمایشگاهی و تحلیلی بر روی بیست نمونه تیر بتنی ساخته شده از پنج مقاومت مختلف بتن به انجام رسیده است. با این‌که نیمی از نمونه‌های یاد شده با ورق‌های CFRP تقویت شده‌اند ولی نیمی دیگر به‌عنوان شاهد مورد مقایسه قرار گرفته‌اند. تقویت تیر ها به‌صورت سه‌وجهی با ورق‌های پلیمری مسلح به الیاف کربنی تک‌سویه CFRP صورت گرفته است. مقاومت چسبندگی CFRP به بستر بتنی با استفاده از روش «پیچش» به‌طور مستقیم اندازه‌گیری گردیده است و نتایج به‌دست آمده با نتایج حاصل از شکست نمونه‌ها در آزمایش استاندارد خمشی مقایسه گردیده‌اند. در نهایت تأثیر مقاومت سطحی بتن و مقاومت چسبندگی CFRP به بتن، بر مقاومت نهایی تیرهای بتنی تقویت شده با ورق‌های CFRP ارائه شده است.

کلیدواژه‌ها

• آزمون پیچش
• مقاومت بتن
• تیر بتنی
• چسبندگی

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عنوان مقاله [English]

Effect(s) of Concrete Strength and its Bond to CFRP sheets on the Ultimate Strength of Concrete Beams

نویسندگان [English]

• mahmood naderi
• ali khonsari

Imam Khomeini International University.

چکیده [English]

Among the systems used for Retrofitting and Strengthening of structures, FRP systems seem to be more popular. When using FRP, the surface strength of concrete plays major role in producing sufficient adhesion between FRP laminates and concrete. Therefore, this paper is devoted to the findings of research on five different concrete strength that were used in manufacturing concrete beams for Retrofitting. In total twenty beams were prepared for studying the changes in adhesion between concrete and CFRP layers. While half of the beams were wrapped with CFRP's, the other half were left as they were for comparative studies. The adhesion of CFRP layers on concrete beams were measured by new Twist-off method and the results were compared with those obtained from standard flexural testing of the beams. Finally, the effect of concrete surface strength and the bond strength of the CFRP on the ultimate strength of the strengthened beams have been assessed.

کلیدواژه‌ها [English]

• Twist-off Method
• Concrete strength
• Concrete beam
• Adhesion

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