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以端弯矩比、长细比和荷载偏心距为主要变化参数,进行了12个方钢管混凝土不等端弯矩偏压柱试验研究。试验结果表明:对于长细比为40.1的试件,端弯矩比对试件破坏形态影响很大,端弯矩比为-1的试件挠曲线为S型,而端弯矩比为1的试件挠曲线为正弦半波;而对于长细比为20.6的短柱试件,端弯矩比对试件破坏形态影响不明显;长细比和偏心距越大,承载力越小;随端弯矩比β从-1～1变化,试件承载力逐渐减小。采用两种计算方法对试件承载力进行了计算,并与试验结果进行对比,计算结果总体低于试验结果。采用有限元软件ABAQUS对方钢管混凝土不等端弯矩偏压柱的受力全过程进行分析,计算得到的试件破坏形态与荷载-变形关系曲线均与试验结果吻合良好。在此基础上,对3种不同端弯矩比的典型算例进行计算,从试件的变形情况、荷载-变形全过程曲线、核心混凝土纵向应力分布及钢管与核心混凝土的相互作用等4个方面对方钢管混凝土不等端弯矩偏压柱的工作机理进行对比分析。研究结果表明:随着端弯矩比由-1～1变化,试件的侧向挠度增大,核心混凝土承担荷载降低,试件承载力降低;所有试件的钢管均表现出良好的约束性能。
Taking end-to-end moment ratio, slenderness ratio and load eccentricity as the main parameters, 12 square concrete-filled square tube concrete columns with unequal moment were tested. The test results show that the bending moment ratio of the specimen with a slenderness ratio of 40.1 has a great influence on the failure morphology of the specimen. The deflection curve of the specimen with an end bending moment ratio of -1 is S type and the end bending moment ratio is 1 The bending curve of the specimen is half sine wave. For the short column with a slenderness ratio of 20.6, the bending moment ratio has no obvious effect on the failure morphology of the specimens. The larger the slenderness ratio and eccentricity are, the smaller the bearing capacity is. The bending moment ratio β varies from -1 to 1, and the bearing capacity of specimens decreases gradually. Two kinds of calculation methods were used to calculate the bearing capacity of the specimen, and compared with the test results, the calculation results were generally lower than the test results. The finite element software ABAQUS was used to analyze the whole force process of the unequal moment bending moment concrete filled steel tubular columns. The calculated fracture morphology and load-deformation curve are in good agreement with the experimental results. On this basis, three typical examples of end-to-end moment ratio are calculated. From the deformation of the specimen, the whole curve of load-deformation process, the longitudinal stress distribution of core concrete and the interaction between steel pipe and core concrete Contrastive analysis was made on the working mechanism of the unequal-moment bending moment columns of CFST. The results show that with the bending moment ratio varying from -1 to 1, the lateral deflection of the specimen increases, the load of the core concrete decreases, and the bearing capacity of the specimen decreases. The steel tubes of all the specimens show good restraining performance .