Bond–slip model for CFRP strips near-surface mounted to concrete

2013 ◽  
Vol 56 ◽  
pp. 945-953 ◽  
Author(s):  
S.S. Zhang ◽  
J.G. Teng ◽  
T. Yu
Keyword(s):  
Slip Model ◽  
Near Surface ◽  
Bond Slip ◽  
Near Surface Mounted

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.

Numerical evaluation of bond–slip relations for near-surface mounted carbon fiber bars embedded in concrete

2013 ◽  
Vol 40 ◽  
pp. 1097-1109 ◽  
Author(s):  
Saptarshi Sasmal ◽  
Chandra Prakash Khatri ◽  
K. Ramanjaneyulu ◽  
V. Srinivas
Keyword(s):  
Carbon Fiber ◽  
Numerical Evaluation ◽  
Near Surface ◽  
Bond Slip ◽  
Near Surface Mounted

scholarly journals Nonlinear 3D Model of Double Shear Lap Tests for the Bond of Near-surface Mounted FRP Rods in Concrete Considering Different Embedment Depth

2021 ◽  
Author(s):  
Yanuar Haryanto ◽  
Hsuan-Teh Hu ◽  
Ay Lie Han ◽  
Fu-Pei Hsiao ◽  
Charng-Jen Teng ◽  
...  
Keyword(s):  
Embedment Depth ◽  
Shear Direction ◽  
Near Surface ◽  
Bond Slip ◽  
Double Shear ◽  
Proposed Model ◽  
Bonded Joint ◽  
Frp Reinforcement ◽  
Near Surface Mounted ◽  
Numerical Finite Element

The utilization of near-surface mounted Fiber Reinforced Polymer (FRP) reinforcement as a method of strengthening in reinforced concrete structures has increased considerably in recent years. Moreover, the application of double-shear lap tests for this rein-forcement method leads to the achievement of a local bond-slip behavior in a bonded joint. This research, therefore, focused on 3-D modeling of this type of test to suitably characterize the bond mechanics between FRP rods and concrete at various embedment depth. The use of different alternatives to represent the interface between the FRP rod and concrete were analyzed after which a comparison was drawn between the numerical finite element (FE) simulations and experimental measurements. The results showed the prediction of the load–slip corresponded with the data obtained from the experiment. Finally, the proposed model has the ability to express the relationship between the penalty stiffness parameters in shear direction Kss = (Ktt) and the embedment depth of FRP rods.

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 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.

scholarly journals Near-Surface Mounted Reinforcement of Sawn Timber Beams-FEM Approach

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2780
Author(s):  
Izabela Burawska-Kupniewska ◽  
Piotr Beer
Keyword(s):  
European Standard ◽  
Near Surface ◽  
Bending Tests ◽  
Starting Point ◽  
Structural Applications ◽  
Bending Stresses ◽  
Complex Models ◽  
Near Surface Mounted ◽  
Sawn Timber ◽  
Timber Beams

The demand for timber has increased significantly in recent years. Therefore, reliable tools are needed to predict the mechanical properties of sawn timber, especially for structural applications. Very complex models require a lot of input data for analysis, which cannot always be guaranteed, especially in industrial practice. Thus, a simplified model for material description was developed and assessed with experiments (static bending tests carried out in accordance with the guidelines suggested in the European standard EN 408) and an analytical approach (gamma method according to the guidelines given in the European standard EN 1995). The effective stiffness was calculated as a major parameter, which has an influence on the elements’ behavior. The model included a near-surface mounted (NSM) local reinforcement technique, with CFRP strips of Scots pine timber beams being subjected to bending stresses. It is anticipated that the developed model can be a starting point for the repair engineering field, contributing to decision-making regarding conservation technique selection and range. Next, improvements of the model will provide more and more realistic results for numerical analysis in terms of the obtained failure mechanisms for sawn timber elements.

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