关键词: 钢管混凝土, 受压构件, 徐变, 含钢率, 偏心率

Abstract: Creep leads to the stress redistribution of Concrete Filled Steel Tubular (CFST) member.According to elastic creep theory and aging-adjustment effective module method,creep stress increment formulas of both steel tube and core concrete for CFST uniaxially and small eccentrically member under long-term action have been put forward.The result of computation is in accordance with that of experiment.The further numerical analysis shows that sectional steel ratio has obvious influence on stress increment of steel tube,but less effect on core concrete.Stress increments of both steel tube and core concrete are linearly changed at same sectional steel ratio while eccentric ratio is raised.Although larger sectional steel ratio could reduce additional internal force of steel tube,steel tube still afford more external force based on the principle of stiffness distributing internal force,which makes total internal force of steel tube still increase and the external force of core concrete obviously reduce.It isn't beneficial for CFST to take full advantage of its performance.

Key words: CFST (Concrete Filled Steel Tubular), compression member, creep, sectional steel ratio, eccentric ratio