مقاوم‌سازی آزمایشگاهی تیرهای بتن مسلح ضعیف با فناوری لایه‌های کامپوزیت سیمانی الیافی مسلح توانمند HPFRCC

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه سمنان

چکیده

وجود سازه ­های قدیمی، ضعف­ های موجود در طراحی و اجرای سازه­ ها، استفاده از مصالح کامپوزیت سیمانی الیافی مسلح توانمند HPFRCC با عملکرد بالا در جهت مقاوم ­سازی، مورد توجه واقع شده است. در این مقاله تأثیر این مصالح بر عملکرد سازه­ای پنج تیر بتن مسلح تقویت شده با این مصالح به ­صورت آزمایشگاهی بررسی گردید. یک تیر مرجع و چهار تیر مقاوم­ سازی شده با یک لایه نازک HPFRCC با الیاف پلی­ پروپیلن با دو نوع مصالح و دو شیوه اجرای متفاوت، تحت آزمایش چهارنقطه­ ای خمش خالص قرار گرفت. نتایج نشان داد که تأثیر مقاوم­ سازی با HPFRCC در شکل ­پذیری نمونه­ ها بیش از تأثیرشان در ظرفیت خمشی تیرها بود و حداکثر افزایش در ضریب شکل ­پذیری و ظرفیت خمشی ناشی از مقاوم ­سازی برابر 64 و 31 درصد بود و سخت­ شوندگی ناشی از پل زدن الیاف در نمودار بار- تغییر مکان نمونه ­های تقویت شده مشهودتر است. میزان جذب انرژی در بهترین نمونه تقویت­ شده با این مصالح تا 90 درصد نسبت به نمونه مرجع افزایش یافت و نتایج آزمایشگاهی تا حدود 11 درصد بیش از مقادیر به ­دست آمده از فرمول­ های تحلیلی بود.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental Strengthening of Deficient RC Beams with Advanced HPFRCC Composite Layers Reinforced with PP Fibers

نویسندگان [English]

  • Mohammad Kazem Sharbatdar
  • Mehdi Ahmadpanahi
Faculty of Civil Engineering, Semnan University, Semnan, Iran
چکیده [English]

The old existing structures and design and construction deficiency are the main to concentrated on using high performance fiber composite HPFRCC for strengthening, Nowadays. Because of increasing demands at the construction industry, it is required to using new material with high quality in this regards. Therefore based on necessities in our country for having high performance composite materials such as HPFRCC, this material are spreadly using as strengthening materials. The main research issues in this regards is on composite ingredients and design mixes, stress-strain curves and material behavior. Even though some structural application are conducted on HPFRCC material (Alwan, 1994; Naaman, 2005), it is required to performing new experimental and analytical researches on material mixes with different fibers and percentages and flexural behavior of reinforced concrete specimens strengthened with this material and their durable performance (Hemmati, 2016; Ehsani, 2019). The effect of structural performance and different arrangements of new material layers of this advanced material on five strengthened reinforced concrete beams was experimentally investigated in this paper and their results were compared to each other’s.

کلیدواژه‌ها [English]

  • Strengthening
  • Experimental Investigation
  • Flexural Behavior
  • Ductility
  • HPFRCC
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