Study of the Behavior of Different Concrete-Filled FRP Tube Columns under Concentric and Eccentric Axial Load

In the recent decades, attention has been focused on the use of fiber-reinforced polymer (FRP) for structural purposes. A new type of FRP use in structures is in the form of concrete filled FRP tube (CFFT) columns. In addition to the added strength and confinement, the FRP tube contains and protects the concrete. In this paper, the behavior of CFFT column under eccentric loading is investigated using finite element simulation. Concrete damaged plasticity model is used for simulation of concrete material behavior. First of all, results of an experimental test is used to verify the accuracy of finite element model predictions. Two experimental test specimens are simulated and analyzed. Comparison of the results between test measurements and model prediction shows a good agreement between the results. Then the effect of FRP thickness, load eccentricity, length-diameter ratio and FRP material on behavior of CFFT column is studied. The results show that when the buckling is governing, higher tube thickness is required to provide ductile behavior. FRP tube does not affect the initial stiffness and only acts after a significant concrete core deterioration. Elasticity modulus and thickness are found to be the most affecting parameters in CFFT behavior. Moreover, it is found that the relation between load eccentricity and CFFT column maximum strength is a quadratic equation

Keywords:

Concrete-filled FRP tube column , load eccentricity , finite element method , concrete damaged plasticity