International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 05 | May -2017
p-ISSN: 2395-0072
www.irjet.net
Numerical Modelling of Concrete Filled Frp Tubes Subjected Under Impact Loading Shine Ancy Cherian1, Afia S Hameed2 1PG
Student, Department of Civil Engineering, SAINTGITS College of Engineering, Kottayam, Kerala, India Professor Department of Civil Engineering, SAINTGITS College of Engineering, Kottayam, Kerala, India ---------------------------------------------------------------------***-------------------------------------------------------------------2Assistant
Abstract - Numerous experimental investigations have
demonstrated the advantages of Concrete Filled FRP Tubes (CFFTs) over, reinforced concrete members under various loading conditions. However none of this studies investigated whether the advantages of CFFTs extends to resist dynamic loads. The high strength to weight ratio of FRP tubes makes them desirable as construction materials. Hollow thin tubes rarely achieve their maximum strength, since they fail prematurely by local buckling. Filling the tubes with concrete is a solution to this problem. Previous research shows that encasing concrete members in a FRP tube protected the concrete and increased the member’s strength. This paper outlines a numerical model built using commercially available software ANSYS 17, in order to predict the response of concrete filled Glass fiber reinforced polymer (GFRP) tubes (CFFTs) and regular round reinforced concrete members to dynamic impact loading. A parametric study is conducted to investigate the effects of thickness of GFRP (Glass Fibre Reinforced Polymer) on the response of CFFTs Key Words: Concrete filled FRP tube (CFFT), Fibrereinforced polymer (FRP) tube, Reinforced concrete 1. INTRODUCTION Civil engineering structures are usually treated in a static manner, in which the applied forces are in equilibrium and they do not produce any dynamic motion. In the case of impact loading, the applied forces are not in equilibrium; thus the structure is set in motion, hence requiring a dynamic analysis to determine response. This dynamic situation requires adjusting the design process, especially in cases where the rate of motion is rapid, since the behavior of construction materials, such as steel and concrete, is rate dependent. Extensive researches show that casting reinforced concrete into FRP tubes increases the structural performance of the system when compared to individual components under static conditions. While the FRP tube’s geometry makes it susceptible to buckling and reinforced concrete is easily cracked and damaged. In addition to the strength and confinement that the FRP tube provides, it contains and protects the concrete. Thus it is evident that the containment and protection of the concrete core by the FRP tube makes it suitable for impact resistant design. This
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motivated in investigating the behavior under impulsive dynamic impact loading. The behaviour of plain and reinforced concrete under impact has been studied for decades such as by Banthia et al. [6] and Bentur et al. [8] and the difficulties in testing and analysis have been recognized and reported by Banthia et al. [7] where they presented details of an impact testing machine in the hope of standardizing the testing procedure. Additionally, the need for a simplified impact design procedure has been recognized and addressed by Kishi and Mikami [2] who developed simplified empirical equations relating the static flexural capacity, impact energy, and either the maximum or the residual displacement. The potential of FRP for improving impact resistance has also been recognized and investigated by researchers such as Tang et al [5] and Yazan and Qaswari [1] who reported favourable results
1.1 CFFT(concrete filled glass fibre reinforced polymer tubes) The high strength to weight ratio of FRP tubes makes them highly desirable as construction materials; however, hollow thin tubes rarely achieve their maximum strength as they tend to fail prematurely by local buckling. Filling the tubes with concrete has been thoroughly researched as a solution to that problem. Son and Fam [4] built a finite element model that predicted and compared the behaviour of hollow and concrete filled GFRP tubes. The model also predicted whether the tube failed by local buckling or material failure. It was found that the flexural strength of the members increases in the longitudinal direction. It was also found that for hollow thin walled tubes, the ultimate strength appeared somewhat independent of fibre orientation when the dominant failure mode was local buckling. In a subsequent study of hollow GFRP tubes, Fam et al. [3] conducted a numerical finite element analysis of cantilevered hollow thin walled slender GFRP tubes under combined axial and lateral loads. The model accounted for both material and ISO 9001:2008 Certified Journal
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