Reinforced Concrete Beams with Carbon-Fiber-Reinforced Polymer Bars—Experimental Study

Innovative reinforcement as fiber-reinforced polymer (FRP) bars has been proposed as alternative for the substitution of the traditional steel bars in reinforced concrete (RC) structures. Although the advantages of this polymer reinforcement have long been recognised, the predominantly elastic response, the reduced bond capacity under repeated load and the low ductility of RC members with FRP bars restricted its wide application in construction so far. In this work, the behavior of seven slender concrete beams reinforced with carbon-FRP bars under increasing static loading is experimentally investigated. Load capacities, deflections, pre-cracking and after-cracking stiffness, sudden local drops of strength, failure modes, and cracking propagation have been presented and commented. Special attention has been given in the bond conditions of the anchorage lengths of the tensile carbon-FRP bars. The application of local confinement conditions along the anchorage lengths of the carbon-FRP bars in some specimens seems to influence their cracking behavior. Nevertheless, more research is required in this direction. Comparisons of experimental results for carbon-FRP beams with beams reinforced with glass-FRP bars extracted from recent literature are also presented and commented. Comparisons of the experimental results with the predictions according to ACI 440.1R-15 and to CSA S806-12 are also included herein.

[1]  A. Ilki,et al.  Monotonic and Cyclic Bond Behavior of Deformed CFRP Bars in High Strength Concrete , 2016, Polymers.

[2]  Constantin E. Chalioris,et al.  Analytical model for the torsional behaviour of reinforced concrete beams retrofitted with FRP materials , 2007 .

[3]  Xiaoshan Lin,et al.  Bond–slip behaviour of FRP-reinforced concrete beams , 2013 .

[4]  Hota V. S. GangaRao,et al.  BENDING BEHAVIOR AND DEFORMABILITY OF GLASS FIBER-REINFORCED POLYMER REINFORCED CONCRETE MEMBERS , 2001 .

[5]  C. Karayannis,et al.  Strengthening and rehabilitation of RC beam–column joints using carbon‐FRP jacketing and epoxy resin injection , 2008 .

[6]  Theodoros C. Rousakis,et al.  RC columns of square section – Passive and active confinement with composite ropes , 2014 .

[7]  Gintaris Kaklauskas,et al.  Comparative analysis of deformations and tension-stiffening in concrete beams reinforced with GFRP or steel bars and fibers , 2013 .

[8]  E. Gudonis,et al.  Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets , 2017, Materials.

[9]  A. G. Tsonos.  Effectiveness of CFRP jackets in post-earthquake and pre-earthquake retrofitting of beam-column subassemblages , 2007 .

[10]  Hui Shen,et al.  Strengthening of Corroded Reinforced SCC-RAP Members with CFRP , 2016 .

[11]  Geminiano Mancusi,et al.  Flexural Behaviour of Concrete Beams Reinforced With GFRP Bars , 2010 .

[12]  A. G. Tsonos.  An innovative solution for strengthening of old R/C structures and for improving the FRP strengthening method , 2014 .

[13]  Kyoungsoo Park,et al.  Punching Shear Behavior of Two-Way Concrete Slabs Reinforced with Glass-Fiber-Reinforced Polymer (GFRP) Bars , 2018, Polymers.

[14]  Francesco Bencardino,et al.  Numerical and analytical modeling of concrete beams with steel, FRP and hybrid FRP-steel reinforcements , 2016 .

[15]  M. Said,et al.  Analytical and experimental flexural behavior of concrete beams reinforced with glass fiber reinforced polymers bars , 2015 .

[16]  Peter H. Bischoff,et al.  Equivalent Moment of Inertia Based on Integration of Curvature , 2011 .

[17]  A. Remennikov,et al.  Experimental investigation of the behaviour of concrete beams reinforced with GFRP bars under static and impact loading , 2016 .

[18]  H. Toutanji,et al.  Flexural behavior of concrete beams reinforced with glass fiber-reinforced polymer (GFRP) bars , 2000 .

[19]  Denvid Lau,et al.  Effect of reinforcement ratio on the flexural performance of hybrid FRP reinforced concrete beams , 2017 .

[20]  M. Konsta-Gdoutos,et al.  Flexural Behaviour of Concrete Beams Reinforced with FRP Bars , 1998 .

[21]  A. Remennikov,et al.  Flexural behaviour of GFRP reinforced high strength and ultra high strength concrete beams , 2017 .

[22]  R. Masmoudi,et al.  Behavior of FRP Bars-Reinforced Concrete Slabs under Temperature and Sustained Load Effects , 2014 .

[23]  Dagmar Svecova,et al.  Critical Review of Deflection Formulas for FRP-RC Members , 2006 .

[24]  Denvid Lau,et al.  Experimental study of hybrid FRP reinforced concrete beams , 2010 .

[25]  A. Ilki,et al.  Seismic Behavior of Substandard RC Columns Retrofitted with Embedded Aramid Fiber Reinforced Polymer (AFRP) Reinforcement , 2015 .

[26]  M. Issa,et al.  Serviceability and ultimate load behavior of concrete beams reinforced with basalt fiber-reinforced polymer bars , 2016 .

[27]  S. Gopinath,et al.  Near surface mounted strengthening of RC beams using basalt fiber reinforced polymer bars , 2016 .

[28]  Panagiotis G. Asteris,et al.  VALIDATION OF ANALYTICAL MODELS FOR THE ASSESSMENT OF BRICK-INFILLED RC FRAMES STRENGTHENED WITH FRPS , 2014 .

[29]  Kypros Pilakoutas,et al.  Bond Behavior of Fiber Reinforced Polymer Bars under Direct Pullout Conditions , 2004 .

[30]  Khaled Soudki,et al.  Evaluation of Shear Design Equations of Concrete Beams with FRP Reinforcement , 2011 .

[31]  M. Motavalli,et al.  Load-carrying capacity of GFRP bars under combined axial force–transverse force loading , 2013 .

[32]  Ehab El-Salakawy,et al.  Finite Element Modeling of GFRP-Reinforced Concrete Interior Slab-Column Connections Subjected to Moment Transfer , 2015 .

[33]  A. Cladera,et al.  Shear design of FRP reinforced concrete beams without transverse reinforcement , 2014 .

[34]  Hany Jawaheri Zadeh,et al.  Reliability Analysis of Concrete Beams Internally Reinforced with Fiber-Reinforced Polymer Bars , 2013 .

[35]  Ibrahim M. Metwally,et al.  Influence of fibers on flexural behavior and ductility of concrete beams reinforced with GFRP rebars , 2011 .

[36]  Nikos A. Papadopoulos,et al.  Investigation of a New Strengthening Technique for RC Deep Beams Using Carbon FRP Ropes as Transverse Reinforcements , 2018, Fibers.

[37]  Amr El-Ragaby,et al.  Effect of the Fiber Type and Axial Stiffness of FRCM on the Flexural Strengthening of RC Beams , 2017 .

[38]  D. J. Kakaletsis.  Comparison of CFRP and Alternative Seismic Retrofitting Techniques for Bare and Infilled RC Frames , 2011 .

[39]  Brahim Benmokrane,et al.  Shear behaviour of geopolymer-concrete beams transversely reinforced with continuous rectangular GFRP composite spirals , 2018 .

[40]  E. El-Salakawy,et al.  Punching Shear Strength of GFRP-RC Interior Slab–Column Connections Subjected to Moment Transfer , 2016 .

[41]  Robert J. Frosch,et al.  CONCRETE SHEAR STRENGTH: ANOTHER PERSPECTIVE , 2003 .

[42]  Fabio Matta,et al.  Modelling and Verification of Response of RC Slabs Strengthened in Flexure with Mechanically Fastened FRP Laminates , 2010 .

[43]  A. G. Tsonos.  Ultra-high-performance fiber reinforced concrete: an innovative solution for strengthening old R/C structures and for improving the FRP strengthening method , 2009 .