Nonlinear cyclic response of laminated glass FRP tubes filled with concrete

Fiber reinforced polymer (FRP) materials are generally known for their linear elastic response to failure. The present study evaluated the implications of using FRP as primary and sole reinforcement for concrete structures in seismic regions through an experimental and analytical investigation on the cyclic response of two different types of laminated glass FRP tubes filled with concrete. The study showed that concrete-filled tubes can be designed with an appropriate laminate structure for a ductility level comparable to that of conventional reinforced concrete columns. The nonlinearity and ductility in these types of structures stem from the off-axis response of the FRP tube. A hysteretic model was developed for the tube, and was cast into a two-dimensional three-node combined fiber element for the concrete-filled FRP tube. Good agreement was shown between the analytical models and the experimental results.