By using a finite element method (FEM), the high temperature behavior of the axially compressed concrete-filled steel tubes (CFST) columns with the square and circular cross section at 400, 500 and 600°C were studied. Material parameters of the steel and concrete were obtained from experimental data and construction codes. Two kinds of steel were investigated, one is a standard SN490B and the other is fire resistant steel SN490C-FR. From our thermoelastic analysis. It is found that the CFST columns with the circular cross section has slightly higher fire resistance than that of columns with the square cross section. However, the square columns exhibit higher creep resistance again creep buckling than the circular columns. The fire resistant steel improves the fire resistance of CFST columns significantly. In addition, at temperature of 400°C, all of columns can stand without failure for over than 10 hours. However, at higher temperatures, concrete is crushed, due to large stress, causing the collapse of CFST columns. The failure modes of CFST columns are classified as the crush of concrete core and buckling under creep.
All Science Journal Classification (ASJC) codes
- 環境科學 (全部)
- 工程 (全部)