圆钢管约束混凝土柱钢管轴压刚度贡献及时效作用影响分析

In this paper, creep tests oil the circular steel tube confined concrete (STCRC) columns are conducted to investigate the lime effects on the axial shortening of STCRC columns, while the solid finite elerneni analysis model using Abaqus are established and validated for the long-term behaviour of such composite columns. Through parameter analysis, the contribution of axial compression stiffness of steel tube in circular steel tube confined reinforced concrete axial compression members and the influence of shrinkage and creep on the contribution of axial compression stiffness of steel tube confined concrete members with different parameters are systematically studied, and the key influencing parameters are determined. Analysis results show that the tube has obvious contribution to both short-term and long-term axial stiffness, which can take up to 15.9% of the total stiffness of the composite members. The increase of the slenderness ratio can significantly increase the short-term and long-term axial stiffness of the tube, which are also more obvious in STCRC columns with lower steel tube ratio. Shrinkage creep will increase the axial compression stiffness of small slenderness ratio members and reduce the axial compression stiffness of large slenderness ratio members, and the influence is more significant in high stress level or high strength concrete members.