Flexural Behavior of Reinforced Concrete Beams with Various Layers of Conventional and Steel Fiber Reinforced Concrete

Year 2022, Volume: 25 Issue: 1, 273 - 280, 01.03.2022

Halit Mertol

https://doi.org/10.2339/politeknik.711975

Cited By: 2

Abstract

Flexural behavior of reinforced concrete (RC) beams having various layers of conventional concrete (CC) and steel fiber reinforced concrete (SFRC) were investigated in this study. Two groups of five beams (180×250×3500 mm) were tested under four-point loading to evaluate the flexural behavior. Both of these groups of beams were reinforced with 416 reinforcing bars. The main variable in this research was the concrete type of the layers throughout the height of the specimen. The height of the cross-section of the beams was divided into 5 layers, each having 50 mm thicknesses. In group “F” specimens, SFRC layers were added to the layers of a CC beam, starting from the bottom, as replacements of CC layers, i.e. F15P10 represented that the bottom 150 mm was cast using SFRC whereas the top 100 mm was cast using CC. In group “P” specimens, CC layers were added to the layers of a SFRC beam, starting from the bottom, as replacements of SFRC layers, i.e. P10F15 represented that the bottom 100 mm was cast using CC whereas the top 150 mm was cast using SFRC. Experimental load-deflection curves were evaluated based on ultimate load, service/post-peak stiffnesses, and flexural toughness. It can be concluded that reasonable ductility may be achieved by adding SFRC at the tension side no matter how thick the layer is and where it is located.

Keywords

Conventional concrete, steel fiber reinforced concrete, service/post-peak stiffness, flexural toughness

Thanks

Special thanks to Dr. Eray Baran from Middle East Technical University and Mohammed Nozad Faeq Faeq for their considerable efforts in this research. The author would like to acknowledge the support of Bekaert and the Technical Manager Mehmet Yerlikaya. I’m also grateful to Hussain Jibril Bello whose previous research contributed immensely to the accomplishment of the present research. The assistance provided by laboratory technicians Ali Sener Dursunoglu and Suayip Ozdemir is also acknowledged.

Farklı Geleneksel ve Çelik Lifli Beton Katmanlarına Sahip Betonarme Kirişlerin Eğilme Davranışı

Abstract

Bu çalışmada, farklı geleneksel ve çelik lifli beton katmanlarına sahip betonarme kirişlerin eğilme davranışı incelenmiştir. Boyutları 180×250×3500 mm olan toplamda 10 kiriş, iki grupa bölünerek dört nokta yüklemesi altında eğilme davranışı değerlendirmesi için test edilmiştir. Tüm kirişlerde çekme bölgesinde 416 donatısı kullanılmıştır. Bu araştırmadaki ana değişken kiriş yüksekliğince oluşturulan katmanlardaki beton tipidir. Kirişin yüksekliği her biri 50 mm olan 5 katmana ayrılmıştır. “F” grubunda bulunan geleneksel beton kullanılan kirişlerde, çelik lifli beton katmanları aşağıdan başlayarak geleneksel beton katmanlarının yerlerine yerleştirilmiştir. Örnek olarak, F15P10 kirişinin yüksekliği boyunca aşağıdan 150 mm’si çelik lifli betondan, yukarıda kalan 100 mm’si ise geleneksel betondan imal edilmiştir. “P” grubunda bulunan çelik lifli beton kullanılan kirişlerde ise, geleneksel beton katmanları aşağıdan başlayarak çelik lifli beton katmanlarının yerlerine yerleştirilmiştir. Örnek olarak, P10F15 kirişinin yüksekliği boyunca aşağıdan 100 mm’si geleneksel betondan, yukarıda kalan 150 mm’si ise çelik lifli betondan imal edilmiştir. Kirişlerin yük-sehim eğrileri elde edilmiş ve bu eğriler azami yük, kullanım rijitliği, tepe sonrası rijitlik ve eğilme tokluğu açısından değerlendirilmiştir. Araştırma sonucunda göre, yeterli sünekliğin çekme bölgesinde bulunan çelik lifli beton katmanı ile sağlanabileceği belirlenmiştir. Bu katmanın, çekme bölgesinde olduğu sürece yüksekliğinin ve yerinin davranışı önemli bir şekilde etkilemediği görülmüştür.  

Keywords

Geleneksel beton, çelik lifli beton, kullanım/tepe-sonrası rijitliği, eğilme tokluğu

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