Experimental study of high strength concrete-filled circular tubular columns under eccentric loading

The paper describes 37 tests conducted on slender circular tubular columns filled with normal and high strength concrete subjected to eccentric axial load. The test parameters were the nominal strength of concrete (30, 70 and 90 MPa), the diameter to thickness ratio D/tD/t, the eccentricity ratio e/De/D and the column slenderness (L/D)(L/D). The experimental ultimate load of each test was compared with the design loads from Eurocode 4, which limits the strength of concrete up to 50 MPa. The aim of the paper is to establish the advisability of the use of high strength concretes as opposed to that of normal strength concretes by comparing three performance indices: concrete contribution ratio, strength index and ductility index. The results show for the limited cases analyzed that the use of high strength concrete for slender composite columns is interesting since this achieves ductile behavior despite the increase in load-carrying capacity is not greatly enhanced.

Research highlights
► High strength concrete for slender concrete-filled columns (HSC-CFT) achieves ductile behavior.
► Load-carrying capacity of HCS-CFT is not greatly enhanced.
► The concrete contribution ratio depends on the relative slenderness and the confinement index.
► The Euro code 4 is accurate for slender high-strength concrete-filled columns.