钢管混凝土受轴向局压荷载时的工作机理研究

采用通用有限元软件ABAQUS对钢管混凝土受轴向局压荷载时的工作机理进行了研究。计算和分析钢管混凝土受局压时的荷载-变形全过程关系曲线,计算曲线与实验曲线吻合较好。通过分析局压面积比、截面含钢率、钢材和混凝土强度以及端板刚度等对钢管混凝土局压力学性能的影响规律,较深入地认识了钢管混凝土受轴向局压荷载时的工作机理。研究表明,在距局压端高度约0.8倍截面直径或1.0倍截面边长的局压影响区内,核心混凝土局压承载强度与塑性性能有所提高,此局压影响区随局压面积比的增大而减小;随着含钢率和钢材强度的增加,钢管混凝土的局压承载力与塑性性能提高;随着混凝土强度的增加,钢管混凝土局压承载力提高,塑性性能降低;随着端板刚度的增加,局压受力性能趋近于全截面受力的情况。最后,在系统参数分析结果的基础上,提出钢管混凝土局压承载力实用计算方法。

Behaviors of concrete-filled steel tubes subject axial local compression

The behavior of concrete-filled steel tubes(CFST)subject to local axial compression is analyzed by using the ABAQUS software.Load-deformation relationship curves of CFST under local compression are calculated and analyzed.The calculated curves agree well with the experiment curves.The influence of local compression area ratio,steel ratio,strength of steel and concrete,rigidity of end plates and so forth on CFST local compression behavior are analyzed.The results indicate that the core concrete bearing strength and plasticity would increase in the local compression influence zone,which is 0.8 times the diameter or 1.0 times the side length of the section of the local compression end.This influence region decreases with the increase of local compression area ratio.The bearing strength and the plasticity increase with the increase of steel ratio and steel strength.The bearing strength increases with the enhanced concrete strength,and the plasticity decreases with the enhanced concrete strength.The behavior of CFST member under local compression tends to approach that of the fully compressed ones with the increasing of end plate rigidity.Finally,based on a systematic parameter analysis,a method of calculating the CFST local compression bearing capacity is proposed.