Compressive behavior of concrete-filled FRP tube columns: Assessment of critical column parameters

A comprehensive experimental program has been underway at the Structures Laboratory of the University of Adelaide to investigate the behavior of concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) under concentric compression. This paper presents the results from a group of 92 selected circular, square, and rectangular CFFTs and discusses the influence of the critical column parameters on the compressive behavior of CFFTs. These parameters include concrete strength, amount and type of FRP tube material, manufacture method of the tubes, and size and shape of the CFFTs. In addition to conventional FRP tubes, new types of tubes with integrated internal FRP reinforcement have been designed and tested. Results indicate that concrete strength, cross-sectional shape, and the amount and type of tube material significantly affect the behavior of CFFTs. The manufacture method of FRP tube also has some, but less significant, influence on the behavior of CFFTs. The influence of specimen size has been found to be small. No apparent difference has been found between the compressive behaviors of circular CFFTs and companion FRP-wrapped cylinders. The results also indicate that newly developed square and rectangular CFFTs, with internal FRP reinforcement, exhibit significantly improved behavior over conventional CFFTs.