scholarly journals Parametric Study of Flexural Strengthening of Concrete Beams with Prestressed Hybrid Reinforced Polymer

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3790 ◽  
Author(s):  
Wang ◽  
Petrů ◽  
Ai ◽  
Ou

The strengthening method of using hybrid fiber reinforced polymer is an effective way to increase the strengthening efficiency and lower the cost. This paper focuses on simulating the flexural behavior of reinforced concrete beam strengthened by prestressed C/GFRP (Carbon-Glass hybrid Fiber Reinforced Polymer) with different hybrid ratios and prestress levels. An elastoplastic damage constitution is used to simulate the mechanical behavior of concrete. A cohesive zone model under mixed mode is adopted to describe the debonding behavior of the FRP-concrete and concrete-steel interface. The results show good agreement with the experiment in the load-deflection curve, load-stress curve of steel, and HFRP. Furthermore, the failure mode of concrete and FRP debonding obtained from numerical simulation is the same as the test. Considering the improvement of the bending capacity, stiffness, and ductility of the strengthened beam in this paper, the best hybrid ratio of carbon to glass fiber is 1:1, and the suitable prestress level is between 30 and 50% of its ultimate strength.

2016 ◽  
Vol 860 ◽  
pp. 156-159
Author(s):  
Seyha Yinh ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas

This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.


2021 ◽  
Vol 309 ◽  
pp. 01172
Author(s):  
G. Prashanth Naik ◽  
K Hemalatha ◽  
Srikanth Konik

This paper present the experimental result of flexural behavior of Hybrid Fiber Reinforced Polymer (HFRP) concrete beams reinforced with Glass Fiber Reinforced Polymer (GFRP) rebars and steel bars. This experiment is conducted with the aim of replacing steel reinforcement with GFRP rebars to reduce the risk of corrosion of steel in concrete structures. The data presented in this study is obtained by conducting flexural test experiment on four beams of HFRP beams with various PVA fibre dosage of 0%, 0.25% and 0.5% and one Pure FRP beam. Fly ash is added by 25% in the mix as a mineral admixture to control the shrinkage cracks. The test result showed that by addition of PVA fibre in HFRP concrete enhance the mechanical properties of beam like deflections, ductility, load carrying capacity and flexural capacity. The optimum dosage of PVA fibre is 0.25%. which improve flexural strength by 200% and 31.1% and ductility increased by 112.2% and 55.12% as compared with Pure FRP beam and HFRP beam without PVA fibre.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yousef Al Rjoub ◽  
Ala Obaidat ◽  
Ahmed Ashteyat ◽  
Khalid Alshboul

PurposeThis study aims to conduct an experimental study and finite element model (FEM) to investigate the flexural behavior of heat-damaged beams strengthened/repaired by hybrid fiber-reinforced polymers (HFRP).Design/methodology/approachTwo groups of beams of (150 × 250 × 1,200) mm were cast, strengthened and repaired using different configurations of HFRP and tested under four-point loadings. The first group was kept at room temperature, while the second group was exposed to a temperature of 400°C.FindingsIt was found that using multiple layers of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) enhanced the strength more than a single layer. Also, the order of two layers of FRP showed no effect on flexural behavior of beams. Using a three-layer scheme (attaching the GFRP first and followed by two layers of CFRP) exhibited increase in ultimate load more than the scheme attached by CFRP first. Furthermore, the scheme HGC (heated beam repaired with glass and carbon, in sequence) allowed to achieve residual flexural capacity of specimen exposed to 400°C. Typical flexural failure was observed in control and heat-damaged beams, whereas the strengthened/repaired beams failed by cover separation and FRP debonding, however, specimen repaired with two layers of GFRP failed by FRP rupture. The FEM results showed good agreement with experimental results.Originality/valueFew researchers have studied the effects of HFRP on strengthening and repair of heated, damaged reinforced concrete (RC) beams. This paper investigates, both experimentally and analytically, the performance of externally strengthened and repaired RC beams, in flexure, with different FRP configurations of CFRP and GFRP.


2020 ◽  
Vol 23 (12) ◽  
pp. 2503-2513
Author(s):  
Xi-Zhi Wu ◽  
Wei-Kang Yang ◽  
Xian-Jun Li

When carbon fiber reinforced polymer is applied to reinforce a steel plate, the end of it tends to debond which could cause a failure. In this article, the finite element model of carbon fiber reinforced polymer–reinforced steel plate was established based on the cohesive zone model and validated by the linear elasticity model and experiments at bonding stage and stripping stage, through which the stripping mechanism of the adhesive layer was studied. It had been proved by the test results of carbon fiber reinforced polymer–reinforced steel plate that the shear stress was the main factor of stripping damage, the whole stripping process consisted of elastic deformation, softening and stripping, and that the stripping began from the end to the middle of carbon fiber reinforced polymer until complete failure. Therefore, the cohesive zone model was suitable for the analysis of carbon fiber reinforced polymer–reinforced steel plate.


Author(s):  
RFN Brito ◽  
RDSG Campilho ◽  
RDF Moreira ◽  
IJ Sánchez-Arce

Adhesive bonding is a predominant bonding technique in the aeronautical and automotive industries. Cohesive zone models, used together with the finite element method, are a viable tool to predict the strength of adhesive joints. The main objective of this study is to evaluate experimentally and numerically (by cohesive zone model) the mechanical performance of carbon-fiber reinforced polymer stepped-lap bonded joints submitted to tensile loads, for different overlap lengths ( LO) and adhesives. The failure mode analysis showed a predominant failure type for all adhesives and good correspondence with the numerical predictions. Normalized peel ( σy) and shear ( τxy) stresses in the adhesive highly increased with LO, which then reflected on different maximum load ( Pm) evolution with LO, depending on the adhesive's ductility. The damage variable SDEG (stiffness degradation) was also evaluated and emphasized on the smaller damage zone at Pm for the brittle adhesive. A significant geometry and material effect were found on Pm of the stepped-lap joints, with benefit for large LO. In this regard, cohesive zone model revealed to be a suitable tool in determining the behavior of different joints. Comparison with joints with aluminum showed that, provided that no carbon-fiber reinforced polymer delamination occurs, stepped-lap joints between carbon-fiber reinforced polymer adherends give better results due to the higher composite stiffness.


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