Flexural Behavior of GFRP Reinforced Concrete Members with CFRP Grid Shear Reinforcements

2006 ◽  
Vol 306-308 ◽  
pp. 1361-1366 ◽  
Author(s):  
Sang Kyoon Jeong ◽  
Seung Sik Lee ◽  
C.H. Kim ◽  
Dong Min Ok ◽  
Soon Jong Yoon

Nowadays, the investigations relating to the FRP re-bars have been increased due to their superior physical and mechanical properties such as environmental resistance, electro-magnetic transparency, and high specific strength and stiffness. In this paper, we present the results of an experimental investigation pertaining to the flexural behavior of concrete beams reinforced with GFRP re-bar bundles for tension and CFRP grids for shear. A total of eight specimens, two pairs of four different shear reinforcement spaces, is loaded to failure under the 4-point bending test set-up. In addition to the experimental investigation, theoretical evaluation is also conducted according to the ACI Committee 440 for all beam specimens. Both experimental and theoretical results such as failure modes and load-deflection relations are compared and good agreements are observed.

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xin Yuan ◽  
Chaoyu Zhu ◽  
Wei Zheng ◽  
Jiangbei Hu ◽  
Baijian Tang

This paper investigates the flexural behavior of CFRP plate-strengthened concrete structures. Specimens of the CFRP plate-reinforced beam were designed and tested by the four-point flexural test. The load-deflection relationship, failure modes, and crack propagation were analyzed. The results showed that the postcracking stiffness and bearing capacity of the test beams can be improved by the additional anchoring measures for CFRP strengthening. The relationship between flexural moment and curvature was analyzed by introducing a MATLAB program. The calculation model between curvature, flexural moment, and stiffness was derived for the CFRP plate-strengthened structure. The recommended calculation model was applied in the analysis of deflection, and the theoretical values were compared with the test results.


2021 ◽  
Vol 30 (1) ◽  
pp. 277-289
Author(s):  
Lee Siong Wee ◽  
Mohd Raizamzamani Md Zain ◽  
Oh Chai Lian ◽  
Nadiah Saari ◽  
Norrul Azmi Yahya

Research on Engineered Cementitious Composites (ECC) is overwhelming owing to its wide structural applications that can serve multi-functional purposes in civil and nvironmental infrastructures. Compared to other high-performance fiber reinforced concrete, ECC yields superior tensile ductility and multiple cracking behaviors when subjected to tensile loadings even with low to moderate volume of fibers. This paper presents the flexural properties of ECC made of cement, an industrial by-product, such as ground granulated blast-furnace slags (GGBS), local silica sand, polyvinyl alcohol (PVA) fiber, water, and superplasticizer (SP). Two series of ECC mixtures (ECC-G50 series and ECC-G60 series) and one control mixture were designed. The effect of two different fiber contents in volume fraction was investigated for the two series of ECC mixtures. The compression and flexural tests were conducted on ECC and control specimens after 28 days of curing. A compression test revealed that almost all ECC mixtures improved compressive strength between 20% to 30% compared to the control specimens. In addition, all ECC plate specimens demonstrated excellent strain-hardening states (i.e., displacement capacity at least ten times greater than the control specimens) and multiple fine-cracks failure modes after the three-point bending test. The increase in fiber content slightly reduced the compressive strength but enhanced the flexural behavior of the ECC-G50 series. However, this observation is not discovered in the ECC-G60 series. Outcomes of this research assist material scientists on the content of PVA fiber and GGBS used in making ECC.


Author(s):  
I.R. Antypes ◽  
◽  
V.V. Zaitsev ◽  

Currently, the use of composite materials is increasingly used in various areas of the national economy, including the aviation industry. The materials of this article are devoted to the study of the use of composite materials for the manufacture of aircraft landing gear in comparison with the traditionally used brand of steel. As a result of the work carried out, it was found that the slope made of carbon fiber showed a critical stress twice as high as its design made of 30xgsn2a steel. In addition, carbon plastics are superior to high-strength steel in terms of specific strength, stiffness, and tensile strength.


2021 ◽  
pp. 152808372110003
Author(s):  
M Atta ◽  
A Abu-Sinna ◽  
S Mousa ◽  
HEM Sallam ◽  
AA Abd-Elhady

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.


2019 ◽  
Vol 28 ◽  
pp. 096369351987741
Author(s):  
Gyula Szabó ◽  
Károly Váradi

The aim of this study is to investigate the global buckling of a relatively long composite cord–rubber tube subjected to axial compression and its cross-sectional instability due to bending by a macromechanical nonlinear finite element (FE) model (nonlinear buckling analysis). Composite reinforcement layers are modelled as transversely isotropic ones, while elastomer liners are described by a hyperelastic material model that assumes incompressibility. Force–displacement, equivalent strain, equivalent stress results along with oblateness and curvature results for the complete process have been presented. It is justified that bending leads to ovalization of the cross section and results in a loss of the load-carrying capacity of the tube. Strain states in reinforcement layers have been presented, which imply that the probable failure modes of the reinforcement layers are both delamination and yarn-matrix debonding. There is a significant increase in strains due to cross-sectional instability, which proves that the effect of cross-sectional instability on material behaviour of the tube is crucial. A parametric analysis has been performed to investigate the effect of the member slenderness ratio on cross-sectional instability of the composite tube. It shows that Brazier force is inversely proportional to the slenderness ratio. It further shows that higher oblateness parameters occur in case of a lower slenderness ratio and that cross-sectional instability takes place at a lower dimensionless displacement in case of a lower slenderness ratio. FE results have been validated by a compression/bending test experiment conducted on a tensile test machine.


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