scholarly journals Bond Coefficient kb of Concrete Beams Reinforced with GFRP, CFRP, and Steel Bars

2021 ◽  
Vol 7 (7) ◽  
pp. 1235-1243
Author(s):  
Naser Kabashi ◽  
Arbër Këpuska ◽  
Enes Krasniqi ◽  
Besart Avdyli

There are several reasons why civil and structural engineers should use Fiber Reinforced Polymer bars in concrete. The primary reason is durability, and other relevant parameters, high strength and, lightweight. Non-corrosive attributes make their use particularly suitable in different situations. Due to low elastic modulus and poor bonding, the use of Fiber Reinforced Polymer results in larger crack widths under serviceability limit state especially beams reinforced with glass fiber bars. The study purpose of this paper is to investigate the kb values. The methodology of this paper is comparing the analytical and experimental results. The investigation included 12 beams, using the four-point load test. The geometrical parameters of tested beams with dimensions: 130×220×2200 mm, reinforced with different diameters, helically-grooved glass fiber bars, and sand-coated carbon fiber bars. The measured cracks were used to assess the current kb values recommended in the design codes and guides. The findings did not support the use of the same kb value for different bars because, in addition to the type of bar, the value of kb is also affected by the type of surface and the diameter of the bar. What is observed based on results shows that CFRP bars have a more constant value depending on the diameter, while GFRP bars have large value changes depending on the diameter. Doi: 10.28991/cej-2021-03091722 Full Text: PDF

1994 ◽  
Vol 116 (3) ◽  
pp. 167-172 ◽  
Author(s):  
P. K. Dutta

Polymeric composites are relatively inexpensive materials of high strength, in which deformation of the matrix is used to transfer stress by means of shear traction at the fiber-matrix interface to the embedded high-strength fibers. At low temperatures, complex stresses are set up within the microstructure of the material as a result of matrix stiffening and mismatch of thermal expansion coefficients of the constituents of the composites. These stresses in turn affect the strength and deformation characteristics of the composites. This is demonstrated by compression testing of an unidirectional glass-fiber-reinforced polymer composite at room and low temperatures. The increase of compressive strength matched the analytical prediction of strength increase modeled from the consideration of increase in matrix stiffness and thermal residual stresses at low temperatures. Additional compression tests performed on a batch of low-temperature thermally cycled specimens confirmed the predictable reduction of brittleness due to suspected increase of microcrack density. The mode of failure characterized by definite pre-fracture yielding conforms more to Budiansky’s plastic microbuckling theory than to Rosen’s theory of elastic shear or extensional buckling.


2016 ◽  
Vol 20 (3) ◽  
pp. 374-393 ◽  
Author(s):  
Le Zhou ◽  
Lianguang Wang ◽  
Liang Zong ◽  
Gang Shi ◽  
Yunhao Bai ◽  
...  

Glass fiber–reinforced polymer tubes filled with steel-reinforced high-strength concrete are proposed as glass fiber–reinforced polymer–steel-reinforced high-strength concrete composite members. Eccentric compression is a typical loading scenario for such column members in practice. Experimental investigation on eight glass fiber–reinforced polymer tubes filled with steel–reinforced high-strength concrete columns subjected to eccentric compression was conducted. The effects of fiber orientation, thickness of glass fiber–reinforced polymer tube, slenderness ratio of columns, and loading eccentricity were investigated. It was found that the compression bearing capacity of glass fiber–reinforced polymer–steel-reinforced high-strength concrete columns increased with the decrease in the fiber tangle angle and the increase in the thickness of the glass fiber–reinforced polymer tube but reduced with the increase in the eccentricity and the slenderness ratio. Corresponding formulas were developed based on the nonlinear full-process analysis theory to describe the compression behavior of glass fiber–reinforced polymer–steel-reinforced high-strength concrete under eccentric loading. Good agreement was found through the comparison between the theoretical and the experimental results. The validated modeling approach was, therefore, employed to develop a parametric analysis that can be used to provide valuable guidance for practical application and further research on such structural members.


Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Gabriel Mansour ◽  
Panagiotis Kyratsis ◽  
Apostolos Korlos ◽  
Dimitrios Tzetzis

There are numerous engineering applications where Glass Fiber Reinforced Polymer (GFRP) composite tubes are utilized, such as desalination plants, power transmission systems, and paper mill, as well as marine, industries. Some type of machining is required for those various applications either for joining or fitting procedures. Machining of GFRP has certain difficulties that may damage the tube itself because of fiber delamination and pull out, as well as matrix deboning. Additionally, short machining tool life may be encountered while the formation of powder like chips maybe relatively hazardous. The present paper investigates the effect of process parameters for surface roughness of glass fiber-reinforced polymer composite pipes manufactured using the filament winding process. Experiments were conducted based on the high-speed turning Computer Numerical Control (CNC) machine using Poly-Crystalline Diamond (PCD) tool. The process parameters considered were cutting speed, feed, and depth of cut. Mathematical models for the surface roughness were developed based on the experimental results, and Analysis of Variance (ANOVA) has been performed with a confidence level of 95% for validation of the models.


Author(s):  
Priyadarsini Morampudi ◽  
Kiran Kumar Namala ◽  
Yeshwanth Kumar Gajjela ◽  
Majjiga Barath ◽  
Ganaparthy Prudhvi

Sign in / Sign up

Export Citation Format

Share Document