LAUSR

Abstract A new composite column of FRP-steel-FRP clad tube (FSFCT) filled with seawater sea-sand coral aggregate concrete (SSCAC) was proposed. The FSFCT is composed of three layers: inner layer of glass fiber reinforced polymer (GFRP) tube, middle layer of carbon steel tube and outer layer of GFRP tube. This novel change allows the FSFCT not only to be filled with SSCAC instead of ordinary concrete but also to be widely used in harsh marine environment. A series of SSCAC filled FSFCT column specimens were prepared to investigate the compressive behavior of the new composite column considering the effects of different thicknesses of inner GFRP tube, middle carbon steel tube and outer GFRP tube. The test results showed that the load-strain curve of SSCAC filled FSFCT column under axial compression had obvious four section characteristics. Compared with steel tube thickness, the effects of outer GFRP tube thickness on the compressive behavior of SSCAC filled FSFCT column were more significant. The ultimate compressive capacity of SSCAC filled FSFCT column was increased by 66.5–131.9% in comparison with SSCAC filled carbon steel tube column with the same steel tube thickness. The confinement effect of outer GFRP tube was much better than that of inner GFRP tube.