MECHANICAL BEHAVIOURS OF ELLIPTICAL CONCRETE-FILLED STEEL TUBULAR MEMBERS UNDER PURE BENDING

A finite element analysis ( FEA) model for elliptical concrete-filled steel tubular member under pure bending is developed by the universal FEA software ABAQUS． The corresponding tests of 6 members under pure bending are conducted to verify the FEA model． It can be found that，in general，good agreement is obtained between the predicted and test results． The FEA model is then used to investigate the mechanism of such composite members further． The stress distribution of the steel tube and the concrete，and the interaction between the steel tube and the core concrete are analyzed． And then，the main parameters influencing the ultimate bearing capacity and the loaddeformation relationship curves under pure bending such as shear span ratio，steel tube strength，concrete strength， major axis length and minor axis length are investigated． The results show the typical failure modes of these members were the lateral overall bending at about mid-length，the yield strength of steel tube，the compressive strength of concrete，the major axis length，the minor axis length and the steel tube wall thickness have obvious effects on their mechanical behavior，while the shear span ratio has slight effect on their mechanical behavior．