Buckling Analysis of Concrete-filled Frp Tubes

Fiber reinforced polymer (FRP) tubes can be filled with concrete to serve as structural columns or piles. The tube provides confinement and strength for the core, whereas the concrete core enhances the overall stability of the system. This paper reports on an analytical and experimental study of the static buckling of thin-walled FRP tubes filled with concrete and bent in single curvature. A comprehensive parametric study on over 11 500 columns shows that concrete-filled FRP tubes are much more susceptible to buckling than concrete columns with internal steel reinforcement. A number of modifications are suggested for the existing stability design equations of critical length and moment magnification of concrete columns to make them applicable to concrete-filled FRP tubes.