شبیه سازی اثرات ورق های FRP روی رفتار غیر خطی اتصالات تیر– ستون بتن مسلح

نعمت زاده, مهدی; بهارلو, سینا; شایان فر, جواد; حسنی, سیدمحمدرضا

doi:10.22091/cer.2021.7364.1296

شبیه سازی اثرات ورق های FRP روی رفتار غیر خطی اتصالات تیر– ستون بتن مسلح

نوع مقاله : مقاله پژوهشی

نویسندگان

¹ گروه مهندسی عمران، دانشکده مهندسی و فناوری، دانشگاه مازندران، بابلسر، ایران

² دانشکده مهندسی و فناوری، دانشگاه مازندران، بابلسر، ایران

³ گروه مهندسی عمران، دانشکده مهندسی و فناوری، دانشگاه مازندران.

⁴ دانشکده عمران، دانشگاه صنعتی نوشیروانی بابل.

10.22091/cer.2021.7364.1296

چکیده

آسیب‏‌پذیری و رفتار لرزه‌‏ای نامناسب اتصالات تیر- ستون در سازه‏های بتنی که براساس آیین‏نامه‏های گذشته و بدون ملاحظات لرزه‏ای طراحی شده‏اند، با توجه به نتایج حاصل از آزمایشگاه و زلزله‏های گذشته اثبات شده است. به منظور ارتقا و بهبود سطح عملکرد سازه‏های قدیمی به سطح عملکرد مورد انتظار آیین‌نامه‌های جدید، در وهله نخست، تعیین نقاط ضعف و رفتار لرزه‏ای سازه و در وهله دیگر، در صورت نیاز به مقاوم‏سازی نقاط ضعف، ارائه یک راه‌حل مقاوم‏سازی مقتضی ضروری می‏باشد. از ‌این‌رو در این تحقیق، تأثیر استفاده از الیاف تقویت‌شده پلیمری در مقاوم‌سازی اتصالات در سطح عضو مورد ارزیابی و بررسی قرار می‏گیرد. در این مقاله، مدلی تحلیلی به منظور شبیه‏سازی رفتار غیرخطی اتصالات مقاوم‌سازی شده با ورق‏های FRP ارائه شده است. در مدل مذکور، رفتار غیرخطی در هسته اتصالات با استفاده از دو فنر محوری مورب شبیه‌سازی می‏شود. خصوصیات بار- تغییرشکل نظیر در فنرهای محوری تابعی از رابطه تنش اصلی کششی- تغییرشکل برشی در هسته اتصال می‌باشد. از این‌رو، براساس مکانیسم رفتاری اتصالات و با استفاده از نتایج آزمایشگاهی، روابط تنش اصلی کششی- تغییرشکل برشی برای اتصالات بتن‌مسلح با مهارهای مختلف آرماتورهای طولی تیر ارائه شده است. مقایسه نتایج حاصل از مدل عددی و نتایج گزارش شده از آزمایشات، قابلیت مدل پیشنهادی در پیش‏بینی رفتار غیرخطی اتصالات مقاوم‏سازی شده با ورق‌های FRP را تأیید کرده است.

کلیدواژه‌ها

موضوعات

روش‌های عددی و آزمایشگاهی

عنوان مقاله [English]

Simulating Effect of FRP Sheets on Nonlinear Behavior of Reinforced Concrete Beam- Column Connections

نویسندگان [English]

Mahdi Nematzadeh ¹
Sina Baharlo ²
Javad Shayanfar ³
Seyed Mohammad Reza Hasani ⁴

¹ Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar, Iran

² Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar, Iran

³ Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar, Iran

⁴ PhD Candidate, Faculty of Civil Engineering, Babol Noshirvani University, Babol, Iran.

چکیده [English]

The vulnerability and improper seismic behavior of beam-column connections in reinforced concrete structures designed based on past codes without seismic considerations has been established through data obtained from experiments and past earthquakes. In this research, the use of fiber-reinforced polymer (FRP) sheets attached to the surface of the member for strengthening connections was investigated. Here, an analytic model was presented for simulating the nonlinear behavior of connections strengthened with FRP sheets. In this model, the nonlinear behavior of the core zone of the connections was simulated with two diagonal linear springs. The corresponding load-displacement relationship in the linear springs is a function of the principal tensile stress-shear deformation in the core zone of the connection. Therefore, based on the behavioral mechanism of the connections and using the experimental results, the principal tensile stress-shear deformation relationships for reinforced concrete connections with different restraints for the longitudinal rebars of the beam were developed. Comparing the results of the numerical model with those obtained from the experiments verified the ability of the proposed model in predicting the nonlinear behavior of connections strengthened with FRP sheets.

کلیدواژه‌ها [English]

Reinforced concrete connections
FRP sheets
nonlinear analysis
seismic strengthening
simulation

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