Abstract:

The stress-strain relationships of concrete filled steel tube(CFST) beam element were concluded from the threedimensional finite element method and the fiber element method. The axial loaded and eccentric compression CFST structures were computed through the beam element method with the two types of stressstrain relationship deduced. The numerical results were compared with the prior test results. The results showed that the accuracy was good when the stress-strain relationship of CFST concluded from fiber element was used. The results were accurate when the stressstrain relation obtained from the three-dimensional finite element method were used in studying square crosssection CFST structures, and the numerical result deviate from experimental results when the stress-strain relationship concluded from three dimensional finite element was used in computing circular cross-section CFST structures.

Key words: concrete filled steel tube, stress-strain relation, numerical studying