Influence of long-term loading on the performance of concrete-filled double skin steel tubular columns : experiments

Concrete-filled double skin steel tubes (CFDST) have been studied by several researchers in the past few years. However, these members when subjected to sustained loading have not been addressed satisfactorily. This paper carried out a series of tests on CFDST columns with circular section inner, square or circular section outer performed under long-term sustained loading condition. The test process included two stages, i.e., long-term service test and ultimate strength test. The long-term deformation of the CFDST columns, as well as the influence of long-term sustained loading on the ultimate strength of the specimens, was investigated experimentally.