scholarly journals Experimental Study of Behaviour of Reactive Powder Concrete Strengthening by NSM-CFRP Corbels

2018 ◽  
Vol 4 (5) ◽  
pp. 980 ◽  
Author(s):  
Abdul Kareem Qasim Mohammad ◽  
Mushriq Fuad Kadhim Al-Shamaa
Keyword(s):  
Carbon Fiber ◽  
Failure Modes ◽  
Load Capacity ◽  
Reactive Powder Concrete ◽  
Near Surface ◽  
Near Surface Mounted ◽  
Effective Depth ◽  
Group B ◽  
Cracking Pattern ◽  
Reactive Powder

The research contain an experimental examination for the behaviour of reactive powder concrete corbels, strengthened with  varying orientation of  Near Surface Mounted Carbon Fiber Reinforcement Polymers (CFRP) strips. Six reactive powder concrete corbels were tested. Divided into two groups, each group contain three specimens, one of them without strengthening takes as control corbel specimen, two corbels in each group strengthened by inclined and horizontal near surface mounted carbon fiber reinforced polymer (NSM-CFRP) stripes, other variable was the shear span to the effective depth ratio (a/d) to study the influences of those variables on the ultimate strength carrying capacity, cracking pattern, cracking load, vertical deflection, failure modes. The results showed an important improvement in the behaviour and load capacity of strengthened reinforced RPC corbels in addition to enhancing the stiffness of corbels. For group A where a/d =0.65, the percentages of increase in load failure were about (10.3% - 15.45%) for inclined and horizontal strengthening respectively, and for group B where  a/d =0.4, the percentages of  increase in load failure were about  (7.1% - 14.6%) for inclined and horizontal strengthening respectively.

scholarly journals Activated Ductile CFRP NSMR Strengthening

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2821
Author(s):  
Jacob Wittrup Schmidt ◽  
Christian Overgaard Christensen ◽  
Per Goltermann ◽  
José Sena-Cruz
Keyword(s):  
Failure Modes ◽  
Elastic Response ◽  
Applied Theory ◽  
Strengthening Effect ◽  
The Novel ◽  
Near Surface ◽  
Linear Elastic ◽  
Near Surface Mounted ◽  
High Elongation ◽  
Strengthened Beam

Significant strengthening of concrete structures can be obtained when using adhesively-bonded carbon fiber-reinforced polymer (CFRP) systems. Challenges related to such strengthening methods are; however, the brittle concrete delamination failure, reduced warning, and the consequent inefficient use of the CFRP. A novel ductile near-surface mounted reinforcement (NSMR) CFRP strengthening system with a high CFRP utilization is introduced in this paper. It is hypothesized that the tailored ductile enclosure wedge (EW) end anchors, in combination with low E-modulus and high elongation adhesive, can provide significant strengthening and ductility control. Five concrete T-beams were strengthened using the novel system with a CFRP rod activation stress of approximately 980 MPa. The beam responses were compared to identical epoxy-bonded NSMR strengthened and un-strengthened beams. The linear elastic response was identical to the epoxy-bonded NSMR strengthened beam. In addition, the average deflection and yielding regimes were improved by 220% and 300% (average values), respectively, with an ultimate capacity comparable to the epoxy-bonded NSMR strengthened beam. Reproducible and predictable strengthening effect seems obtainable, where a good correlation between the results and applied theory was reached. The brittle failure modes were prevented, where concrete compression failure and frontal overload anchor failure were experienced when failure was initiated.

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.

scholarly journals Inclusion of CFRP-Epoxy Composite for End Anchorage in NSM-Epoxy Strengthened Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Md. Akter Hosen ◽  
Mohd Zamin Jumaat ◽  
A. B. M. Saiful Islam
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Cover ◽  
Structural Members ◽  
Premature Failure ◽  
Near Surface ◽  
Steel Bars ◽  
Near Surface Mounted ◽  
Separation Failure ◽  
Concrete Cover Separation

Nowadays, the use of near surface mounted (NSM) technique strengthening reinforced concrete (RC) structural members is going very popular. The failure modes of NSM strengthened reinforced concrete (RC) beams have been shown to be largely due to premature failure such as concrete cover separation. In this study, CFRP U-wrap end anchorage with CFRP fabrics was used to eliminate the concrete cover separation failure. A total of eight RC rectangular beam specimens of 125 mm width, 250 mm depth, and 2300 mm length were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM steel bars and the remaining four specimens were strengthened with NSM steel bars together with the U-wrap end anchorage. The experimental results showed that wrapped strengthened beams had higher flexural strength and superior ductility performance. The results also show that these beams had less deflection, strain, crack width, and spacing.

scholarly journals Experimental and Numerical Study of Behaviour of Reinforced Masonry Walls with NSM CFRP Strips Subjected to Combined Loads

Buildings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 103
Author(s):  
Houria Hernoune ◽  
Benchaa Benabed ◽  
Antonios Kanellopoulos ◽  
Alaa Hussein Al-Zuhairi ◽  
Abdelhamid Guettala
Keyword(s):  
Failure Modes ◽  
Numerical Study ◽  
Masonry Wall ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Near Surface ◽  
Combined Loads ◽  
Reinforced Masonry ◽  
Brick And Mortar ◽  
Near Surface Mounted

Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) walls using the detailed micro-modelling approach (DMM) by means of ABAQUS software. In this analysis, the non-linearity behavior of brick and mortar was simulated using the concrete damaged plasticity (CDP) constitutive laws. The results proved that the application of the NSM-CFRP strips on the masonry wall influences significantly strength, ductility, and post-peak behavior, as well as changing the failure modes. The adopted DMM model provides a good interface to predict the post peak behavior and failure mode of unreinforced brick masonry walls.

scholarly journals Characterization and Simulation of the Bond Response of NSM FRP Reinforcement in Concrete

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1770 ◽  
Author(s):  
Javier Gómez ◽  
Lluís Torres ◽  
Cristina Barris
Keyword(s):  
Load Capacity ◽  
Numerical Procedure ◽  
Fiber Reinforced Polymer ◽  
Near Surface ◽  
Bond Slip ◽  
Pull Out ◽  
Reinforced Polymer ◽  
Frp Reinforcement ◽  
Near Surface Mounted ◽  
Shear Stress And Strain

The near-surface mounted (NSM) technique with fiber reinforced polymer (FRP) reinforcement as strengthening system for concrete structures has been broadly studied during the last years. The efficiency of the NSM FRP-to-concrete joint highly depends on the bond between both materials, which is characterized by a local bond–slip law. This paper studies the effect of the shape of the local bond–slip law and its parameters on the global response of the NSM FRP joint in terms of load capacity, effective bond length, slip, shear stress, and strain distribution along the bonded length, which are essential parameters on the strengthening design. A numerical procedure based on the finite difference method to solve the governing equations of the FRP-to-concrete joint is developed. Pull-out single shear specimens are tested in order to experimentally validate the numerical results. Finally, a parametric study is performed. The effect of the bond–shear strength slip at the bond strength, maximum slip, and friction branch on the parameters previously described is presented and discussed.

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