scholarly journals Effectiveness of Various Techniques Using FRP for the Strengthening of R. C. Beams with Tension Lap Splices

2019 ◽  
pp. 1-18
Author(s):  
Mohamed H. Makhlouf
Keyword(s):  
Bond Strength ◽  
Cross Section ◽  
Epoxy Adhesive ◽  
Experimental Program ◽  
Near Surface ◽  
Lap Splices ◽  
Lap Splice ◽  
Flexural Performance ◽  
Externally Bonded ◽  
Near Surface Mounted

This paper presents an experimental program conducted to investigate the flexural performance of RC beams with tension reinforcement lap splice strengthened using externally bonded FRP different techniques in splice region. The specimens were reinforced on the tension side with four deformed bars spliced at mid span. The tested beams are of 3200 mm total length and 250*120 mm cross section, tested in positive bending. The considered parameters were splice length, type of FRP (glass or carbon), strengthening techniques in splice region (externally confine strips around cross section, Near Surface Mounted technique "NSM" stirrups, externally bonded sheets or bars on the tension face, number of GFRP strips layers (one layer, two layers, and three layers), and shape of NSM stirrups (Box or U shape). No additional anchorage mechanism or bonding methodology was applied for the FRP strips on the concrete except the epoxy adhesive. The effect of these factors on the failure of modes, the ultimate load, the bond strength and that the ductility were investigated. The results indicated that all applied strengthening techniques were efficient in improving the bond strength of the lap splices, the ductility, and the load-deflection behavior of the tested beams, especially when strips were installed over the splice region. This study approved that NSM technique gave more prominent simplicity of employ.

Comparison of Various Techniques for Flexural Strengthening of Thin Concrete Members Using Continuous Carbon Fibers

2015 ◽  
Vol 1120-1121 ◽  
pp. 1458-1462
Author(s):  
Andrej Ivanič ◽  
Samo Lubej
Keyword(s):  
Carbon Fibers ◽  
Flexural Stress ◽  
Near Surface ◽  
Flexural Strengthening ◽  
Flexural Performance ◽  
Concrete Members ◽  
Modes Of Failure ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Strengthening Technique

This paper deals with flexural performance of thin concrete members reinforced with continuous carbon fibers in the form of filament yarns. The laboratory specimens were tested under static loading conditions to investigate the effects of three different strengthening techniques on flexural stress, mid-span deflection and modes of failure. The specimens were strengthened in flexure using carbon fiber yarns as near-surface mounted, externally bonded and placed in the geometric center of the specimen, respectively. Based on this investigation, the advantages and shortcomings of individually strengthening technique can be drawn.

scholarly journals Bond Behaviour of Near-Surface Mounted Strips in RC Beams—Experimental Investigation and Numerical Simulations

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4362
Author(s):  
Renata Kotynia ◽  
Hussien Abdel Baky ◽  
Kenneth W. Neale
Keyword(s):  
Concrete Strength ◽  
Element Model ◽  
Steel Reinforcement ◽  
Reinforcement Ratio ◽  
Experimental Program ◽  
Fe Model ◽  
Bond Behaviour ◽  
Near Surface ◽  
Cfrp Laminates ◽  
Near Surface Mounted

This paper presents an investigation of the bond mechanism between carbon fibre reinforced polymer (CFRP) laminates, concrete and steel in the near-surface mounted (NSM) CFRP-strengthened reinforced concrete (RC) beam-bond tests. The experimental program consisting of thirty modified concrete beams flexurally strengthened with NSM CFRP strips was published in. The effects of five parameters and their interactions on the ultimate load carrying capacities and the associated bond mechanisms of the beams are investigated in this paper with consideration of the following investigated parameters: beam span, beam depth, longitudinal tensile steel reinforcement ratio, the bond length of the CFRP strips and compressive concrete strength. The longitudinal steel reinforcement was cut at the beam mid-span in four beams to investigate a better assessment of the influence of the steel reinforcement ratio on the bond behaviour of CFRP to concrete bond behaviour. The numerical analysis implemented in this paper is based on a nonlinear micromechanical finite element model (FEM) that was used for investigation of the flexural behaviour of NSM CFRP-strengthened members. The 3D model based on advanced CFRP to concrete bond responses was introduced to modelling of tested specimens. The FEM procedure presents the orthotropic behaviour of the CFRP strips and the bond response between the CFRP and concrete. Comparison of the experimental and numerical results revealed an excellent agreement that confirms the suitability of the proposed FE model.

scholarly journals Strengthening of RC Beams Using Externally Bonded Reinforcement Combined with Near-Surface Mounted Technique

Polymers ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 261 ◽  
Author(s):  
Kh Darain ◽  
Mohd Jumaat ◽  
Ahmad Shukri ◽  
M. Obaydullah ◽  
Md. Huda ◽  
...  
Keyword(s):  
Rc Beams ◽  
Near Surface ◽  
Externally Bonded ◽  
Near Surface Mounted

Structural Behavior of Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforcement Polymer Plate

2013 ◽  
Vol 302 ◽  
pp. 338-342
Author(s):  
Soo Yeon Seo
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforcement ◽  
Reinforced Concrete Beams ◽  
Structural Behavior ◽  
Rc Beam ◽  
Near Surface ◽  
Cfrp Plate ◽  
Carbon Fiber Reinforcement ◽  
Externally Bonded ◽  
Near Surface Mounted

This paper presents the study to find retrofit effect in case of Near-Surface-Mounted Retrofit (NSMR) using Carbon Fiber Reinforcement Polymer (CFRP) plate targeting reinforcement concrete (RC) beam by comparing the previous Externally Bonded Retrofit (EBR) method through experimental analytical works. Three RC beam specimens were made and two of them were retrofitted with CFRP plate by using EBR and NSMR. Also Finite Element (FE) analysis was performed in order to simulate the structural behavior of the beams by considering the bond properties between concrete and CFRP. From the study, it was found that the beam retrofitted with EBR hada reduction of bond capacity in the joint while the beam retrofitted with NSMR had perfect bond capacity.

Comparative study on the flexural strengthening of RC beams using EB CFRP sheets, NSM CFRP bars, P-SWRs, and their combinations

2020 ◽  
pp. 136943322097172
Author(s):  
Yihua Zeng ◽  
Xinghua Li ◽  
Amira Hamdy Ali Ahmed ◽  
Gang Wu
Keyword(s):  
Steel Wire ◽  
Experimental Investigations ◽  
Near Surface ◽  
Flexural Strengthening ◽  
Wire Ropes ◽  
Cfrp Sheets ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Strengthening Technique ◽  
Space Requirements

The externally bonded (EB) carbon fiber reinforced polymer (CFRP), near-surface-mounted (NSM) CFRP and the prestressed steel wire ropes (P-SWRs) has been proven to be feasible and reliable flexural strengthening methods for concrete structures. However, debonding issues in EB CFRP sheets (or NSM CFRP bars) and space requirements for edge and spacing clearance of NSM CFRP bars (or P-SWRs) has limited the application of these three strengthening techniques. Therefore, the combinations of these methods need to be investigated and clarified. In this paper, experimental investigations on the flexural performances of seven concrete beams are presented, in which three of the beams were separately strengthened with EB CFRP sheets, NSM CFRP bars, and P-SWRs, respectively, and three of the beams were combinedly strengthened with two of the three techniques. Test results demonstrated that the flexural performances of beams strengthened with the combination with EB CFRP sheets, NSM CFRP bars, and P-SWRs are between the flexural performances of the beams strengthened with the corresponding individual strengthening techniques. It is found that the P-SWRs is favorable for combinations. In case the P-SWRs was combined with EB CFRP sheets or NSM CFRP bars for strengthening, the cracking load was increased to more than 230% and the maximum ultimate load-bearing capacity was increased to 150% when compared with the control beam. The debonding which occurred more or less in the beams strengthened with EB CFRP sheets or NSM CFRP bars or their combination was successfully eliminated by using the combination strengthening technique with P-SWRs. Also, the combination of P-SWRs with EB CFRP sheets or NSM CFRP bars is also favorable to improve the ductility of strengthened beams.

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