scholarly journals Strengthening of Bent LVL Beams with Near-Surface Mounted (NSM) FRP Reinforcement

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2350 ◽  
Author(s):  
Michał Marcin Bakalarz ◽  
Paweł Grzegorz Kossakowski ◽  
Paweł Tworzewski
Keyword(s):  
Bending Moment ◽  
Experimental Tests ◽  
Fiber Reinforced Polymer ◽  
Wood Structures ◽  
Near Surface ◽  
Bending Tests ◽  
Laminated Veneer Lumber ◽  
Reinforced Polymer ◽  
Frp Reinforcement ◽  
Near Surface Mounted

The topic of the article is the analysis of the static work of unreinforced and reinforced with composite material timber beams under bending tests. The results of the experimental tests and a brief outline of the characteristics of the internal reinforcement of wood structures are presented. Experimental tests were performed on full-scale beams made of laminated veneer lumber (LVL) with nominal dimensions of 45 × 200 × 3400 mm. Two strips of carbon fiber-reinforced polymer (CFRP) reinforcement were glued into rectangular grooves in the component bottom with two-component epoxy resin (0.62% reinforcement percentage). The reinforcement mainly affected the enhancement of the maximum bending moment values evaluated at the points of application as having concentrated forces of 32% and 24% in comparison to the unreinforced elements. Increases of 11% and 7% in the global modulus of elasticity in the bending and stiffness coefficients were achieved, respectively. The failure of the reference beams was caused by exceeding the tensile strength of the LVL. The reinforced elements were characterized by a greater variation in failure mode, resulting from tension, compression or lateral torsional buckling. The strain profile reading showed a higher utilization of the compression characteristic of veneer in specimens reinforced with carbon laminates.

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.

Characterization of combined longitudinal and transverse FRPs for strengthening concrete columns

2020 ◽  
Vol 47 (6) ◽  
pp. 718-728
Author(s):  
Pedram Sadeghian ◽  
Brandon Fillmore
Keyword(s):  
Bending Moment ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Near Surface ◽  
Strain Behavior ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
Near Surface Mounted ◽  
Glass Frp

This paper presents the results of a study on the characterization of combined longitudinal near-surface-mounted (NSM) fiber-reinforced polymer (FRP) bars and transverse FRP wraps for strengthening concrete columns. A total of 21 concrete cylinders were prepared, strengthened, and tested to characterize the performance of the strengthening system. Three arrangements of glass FRP (GFRP) bars were mounted in surface grooves, and unidirectional basalt FRP (BFRP) composite was used to wrap the specimens. It was shown that the wrapping system effectively prevented premature failures of the NSM bars and extended the contribution of the bars from a mean of 17.5% in the NSM specimens to a mean of 27.7% in the specimens strengthened with the combined NSM and transverse FRPs. An analytical model was also presented to predict the load–strain behavior and the effect of combined axial load and bending moment.

scholarly journals Numerical Analysis of the Flexural Response of Rc Beams Strengthened with NSM-CFRP

2018 ◽  
Vol 28 (3) ◽  
pp. 90-102
Author(s):  
Ahmed Khene ◽  
Habib Abdelhak Mesbah ◽  
Nasr-Eddine Chikh
Keyword(s):  
Parametric Study ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Near Surface ◽  
Flexural Response ◽  
Reinforced Polymer ◽  
Near Surface Mounted ◽  
Concrete Coating ◽  
A New Technique ◽  
Nsm Technique

Abstract In this study, we have chosen to use a new technique of reinforcement with composite materials, namely the near surface mounted technique (NSM). The NSM technique consists in inserting strips of carbon fiber reinforced polymer (CFRP) laminate into slits made beforehand at the level of the concrete coating of the elements to be reinforced. A numerical investigation was conducted on rectangular reinforced concrete beams reinforced with NSM-CFRP using the ATENA finite element code. A parametric study was also carried out in this research. The numerical results were compared with the experimental results of the beams tested by other researchers with the same reinforcement configurations. Overall, numerical behavior laws are rather well-suited to those obtained experimentally and the parametric study has also yielded interesting results.

GRP Composite Pipe Elbows Subject to an Internal Pressure and In-Plane Bending: An Experimental Study

2020 ◽  
Author(s):  
Brian Ellul Grech ◽  
Michael A. Dimech ◽  
Duncan Camilleri ◽  
Martin Muscat
Keyword(s):  
Bending Moment ◽  
Experimental Tests ◽  
Positive Pressure ◽  
Bending Tests ◽  
Failure Initiation ◽  
Pipe Elbow ◽  
Reinforced Polymer ◽  
Manufacturing Procedure ◽  
Plane Bending ◽  
Stiffening Effect

Abstract The use of polymer composite materials in the piping industry is increasingly gaining popularity. However, the design rules of these novel materials are relatively more complex and high safety factors are applied, requiring costly experimental validation. Experimental tests on e-glass reinforced polymer (GRP) pipe elbows is limited and in view of these challenges, this study presents a set of experimental results obtained from a series of pressurization and in-plane bending tests of polyester pipe elbows reinforced with e-glass chopped strand and woven roving mats. Details of the specimen manufacturing procedure, testing fixture and loading setup, are also given. A data acquisition system was setup to control, monitor and record the applied loads, the resulting meridional and hoop strains around the mid-plane of the elbows. A total of 3 specimens were tested where the first specimen was subject to an increasing positive pressure until global failure and was used to serve as a benchmark for the other two specimens. The latter were similarly subject to a positive pressure limited to the first-ply-failure load region established from the initial test. Both specimens were unpressurized and then subjected to a two cycle opening and unloading in-plane bending moment. Results show that the GRP pipe elbows were capable of sustaining loads beyond the identified failure initiation and successive bending cycles produced pipe elbow stiffening effect.

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