scholarly journals Modeling of CFRP strengthened RC beams using the SNSM technique, proposed as an alternative to NSM and EBR techniques

2020 ◽  
Vol 14 (54) ◽  
pp. 21-35
Author(s):  
Adel Boulebd ◽  
Ferhoune Noureddine ◽  
Boukhezar Mohcene ◽  
Habib Abdelhak Mesbah
Keyword(s):  
Finite Element ◽  
Failure Mode ◽  
Numerical Study ◽  
Concrete Cover ◽  
Rc Beams ◽  
Near Surface ◽  
Externally Bonded ◽  
Bending Capacity ◽  
Near Surface Mounted ◽  
Abaqus Software

In this paper, an analytical and numerical study in FEM finite element by the ABAQUS software was conducted. Which aims to study the behaviour of RC beams bending strengthened with SNSM side near surface mounted technique, proposed as a solution to avoid the failure mode by debonding of the strengthening, the disadvantage of the EBR externally bonded reinforced technique, and the failure mode by separation of the concrete cover relative to the NSM near surface mounted technique, by comparing the behaviour of the three techniques, the effect of the quantity of strengthening and confirm the results with the literature. The results of this study show that the numerical and analytical model can predict the behaviour of strengthened RC beams according to the three techniques, a clear improvement of the bending capacity of beams strengthened is noticed. A good preservation of the ductility of SNSM beams with a better failure mode.

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

Research on Rc Beams Strengthened with near-Surface Mounted Helical Rib Bar

2011 ◽  
Vol 90-93 ◽  
pp. 1757-1760
Author(s):  
Zhen Hua Ren ◽  
Xian Tao Zeng ◽  
Han Long Liu
Keyword(s):  
Crack Resistance ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Concrete Cover ◽  
Experimental Results ◽  
Rc Beams ◽  
Near Surface ◽  
Near Surface Mounted ◽  
Strengthened Beam

Four concrete beams were cast with normal reinforcement bars. According to different the amount of mounted strengthening, grooves are opened in the concrete cover of tensile region in the concrete beams. Helical Rib Bar（HRB）is inserted in the grooves that is filled with resin. Flexural experimental results indicate that the limit bearing capacity, rigidity and crack resistance of beams strengthened with HRB are all improved obviously. With the increase in the amount of mounted strengthening, the limit bearing capacity of the strengthened beam is improved obviously. In comparison with the contrastive beam, the limit bearing capacity of the beam strengthened with one near-surface mounted HRB is increased by 20.91%, and that of the beam strengthened with two near-surface mounted HRB is increased by 54.55%，and that of the beam strengthened with three near-surface mounted HRB is increased by 90.91%.

scholarly journals Assessment of RC elements strengthened with NSM FRP rods by experimental tests

2020 ◽  
Vol 323 ◽  
pp. 01008
Author(s):  
Roberto Capozucca ◽  
Erica Magagnini
Keyword(s):  
Experimental Tests ◽  
Concrete Cover ◽  
Beam Model ◽  
Rc Beams ◽  
Near Surface ◽  
Beam Elements ◽  
Damage Degree ◽  
Reinforced Polymer ◽  
Near Surface Mounted ◽  
Vibration Tests

Near surface mounted (NSM) technique of strengthening with FRP rods inserted in grooves on the concrete cover of damaged RC beams has been improved in recent years. The aim of this paper is the examination of the static and dynamic behaviour of undamaged and damaged reinforced concrete (RC) beams with free-free ends. RC beams strengthened with NSM Glass and Carbon fiber reinforced polymer (G-CFRP) rods have been experimentally analysed. The damage of the RC beam model was obtained by the cracking of concrete under bending tests. The detection of damage and monitoring of RC beams with and without strengthening were carried out by vibration tests assuming free-free ends at different degree of damage. Envelope diagrams of Frequency Response Functions (FRFs) obtained by the dynamic experimental tests are shown and the changes of natural frequency values are correlated to the damage degree of beam elements. Experimental results are discussed with particular emphasis on the aspect of the loss of bond.

scholarly journals Crack parameters in normal section of FRP strengthened RC elements

2019 ◽  
Author(s):  
Justas Slaitas ◽  
Juozas Valivonis
Keyword(s):  
Prediction Model ◽  
Crack Width ◽  
Rc Beams ◽  
Near Surface ◽  
Normal Section ◽  
Full Development ◽  
Externally Bonded ◽  
Frp Reinforcement ◽  
Near Surface Mounted ◽  
Element Failure

Contrary to existing studies, this paper presents a prediction model of crack parameters in normal section of FRP strengthened RC elements neglecting crack spacing. A relation between normal crack width, depth and strains in the level of FRP reinforcement, established by Slaitas et al. (Slaitas, Daugevičius, Valivonis, & Grigorjeva, 2018a) and Jokūbaitis et al. (Jokūbaitis & Juknevičius, 2013; Jokūbaitis, Juknevičius, & Šalna, 2013), allowed authors to describe the full development of the crack up to the element failure. Numerical results are compared with experimental ones from the tests of 9 RC beams, strengthened with externally bonded and near surface mounted FRP reinforcements.

scholarly journals Torsional Strengthening of RC Beams with Near-Surface Mounted Steel Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Nasih Habeeb Askandar ◽  
Abdulkareem Darweesh Mahmood
Keyword(s):  
Twist Angle ◽  
Bending Moment ◽  
Rc Beams ◽  
Near Surface ◽  
Concrete Members ◽  
Epoxy Adhesives ◽  
Steel Bars ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Combined Actions

The strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and near-surface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening. Therefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. The practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. The torsional performance of the RC beams was significantly improved by using NSM steel bars, whereas in various NSM configurations, the 90° NSM beams outperformed the 45° NSM beams.

scholarly journals Effects of RC beams reinforcement using near surface mounted reinforced FRP composites

2010 ◽  
Vol 8 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Slobodan Rankovic ◽  
Radomir Folic ◽  
Marina Mijalkovic
Keyword(s):  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Near Surface ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Reinforced Beams ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Basic Characteristics ◽  
Frp Bars

This paper analyzes application of modern reinforcement methods for reinforced concrete (RC) beams using fiber-reinforced polymer (FRP) materials. Basic characteristics of FRP materials and the method of mounting the FRP bars within concrete, that is, near the surface of the beams (NSM method) are presented. The properties of this method and its advantages in comparison to externally bonded reinforcement laminate method (EBR) have been analyzed. The results of measured deflections and width of the cracks of the beams reinforced by FRP bars, depending on the load are presented and discussed, in comparison to the results obtained from the non-reinforced beams. The experimental research was published at the Faculty of Civil Engineering and Architecture of Nis in 2009.

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