Improving Shear Capacity and Ductility of Shear-deficient RC Beams Using CFRP Strips

Abstract

The results of an experimental investigation are presented in this article for improving the shear capacity and ductility of reinforced concrete beams by using CFRP strips. The purpose of this study is to obtain ductile flexural behavior for shear-deficient reinforced concrete beams. The experimental program consisted of 10 T cross-sectioned half scale simply supported beam specimens, seven of which were constructed with deficient shear reinforcement and the remaining three without any shear reinforcement. One beam was used as a reference and nine beams were strengthened using U-shaped CFRP strips with or without fan type anchorage. Three different CFRP strip spacing such as sf = 125 mm, 150 mm, and 200 mm were used. The effect of anchorages that were used at the ends of the strips on shear strength and behavior of the strengthened specimens was investigated. CFRP strips without anchorages improved the shear strength, but no flexural behavior was observed. specimens failed with brittle shear failure due to peeling of CFRP strip from RC beam surfaces. specimens with deficient shear reinforcement that were strengthened with anchored CFRP strips showed improved shear strength and ductile flexural behavior was observed. Similar behaviors were observed for specimens even without any shear reinforcement. When the CFRP strip strains of the specimens with anchorages and without anchorages were compared, maximum strains at anchored strips were approximately 56% larger than that of without anchorages.

An anticipated shear design method for reinforced concrete beams strengthened with anchoraged carbon fiber‐reinforced polymer by using neural network

“…An extensive literature review has been carried out to collect test data of RC beams strengthened with anchoraged FRP composites. Seventy-three RC beams strengthened with anchoraged FRP reinforcements were collected from the literature (Sato et al, 1997;Mitsui et al, 1998;Khalifa et al, 1999;Nanni, 2000, 2002;Chaallal et al, 2002a;Li et al, 2002;Adhikary et al, 2004;Xuesong and Zhongfan, 2004;Anil, 2006Anil, , 2008Bousselham and Chaallal, 2006;Monti and Liotta, 2007;Sakar, 2008Sakar, , 2009Quinn, 2009;Altin et al, 2010;Chaallal et al, 2002). Subsequently, six sheardeficient RC beams strengthened with different CFRP configurations were tested in the laboratory by the author (Tanarslan et al, 2008;Tanarslan, 2010a).…”

Textile Types, Number of Layers and Wrapping Types Effect on Shear Strengthening of Reinforced Concrete Beams with Textile-Reinforced Mortar versus Carbon-Fiber-Reinforced Polymer

“…In the literature on strengthening, strengthening with the FRP method, which is older than the TRM method, has been used effectively from the beginning of the 2000s to the present [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. The study conducted by Triantafillou (1998) [40] is one of the pioneering studies on the strengthening of reinforced concrete beams with FRP against shear.…”

Shear Capacity of Reinforced Concrete T-Beams Retrofit with Externally Bonded CFRP Fabric: A New Perspective

“…US code ACI 440.2R-17 (ACI 2017) adopts a similar approach but includes an additional empirically determined concrete contribution. Experimental studies have been carried out using realistically sized T-beam specimens retrofit with externally bonded U-wrapped unidirectional CFRP fabric in continuous sheets or discrete strips (Deniaud and Cheng 2001, Bousselham and Chaallal 2006, Altin et al 2010, Gamino et al 2010, Dias and Barros 2010, Mofidi and Chaallal 2011, Dirar et al 2012, Belarbi et al 2012, Ozden et al 2014, Mofidi and Chaallal 2014b, Qin et al 2015, Foster et al 2017a, Benzeguir et al 2018, Oller et al 2019; providing a sizable, though far from comprehensive, empirical benchmark against which to evaluate existing guidance.…”