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为了克服目前钢管混凝土L形柱钢板存在90°阴角,钢管与核心混凝土之间相互作用相对较弱的缺点,提出了多室式钢管混凝土组合L形柱,是由三根矩形钢管型材焊接形成多室式异形钢管,再向其中浇筑混凝土而成。为更准确地确定该种组合构件截面形心的位置,给出了用刚度换算截面法确定其截面形心的计算过程。探讨了L形截面钢管混凝土构件弯曲屈曲长细比和弯扭屈曲换算长细比的计算方法。建立了多室式钢管混凝土组合L形柱的有限元模型。通过对其轴压短柱计算结果的分析,分析了截面的变形特点及工作机理。通过对其轴压长柱进行的特征值屈曲分析,比较了构件绕两个主轴屈曲时的变形特点及相应弹性屈曲临界力的大小。通过对其中长柱进行的非线性屈曲分析,分析了构件长度、钢材屈服强度、初偏心方向等参数对构件受力性能的影响,提出了中长柱稳定系数的计算公式。结果表明:多室式钢管混凝土组合L形柱可减小阴角部位钢管的变形,增加钢管对混凝土的约束作用;在长细比较小时,绕对称轴的弯扭屈曲起控制作用,但当长细比较大时,绕非对称轴的弯曲屈曲起控制作用;在一端固定一端自由端的条件下,按非线性屈曲分析,不同偏心方向的受压承载力区别不大,但仍以绕非对称轴方向弯曲的承载力最低。
In order to overcome the shortcoming that the existing L-shaped column of steel-reinforced concrete has a negative angle of 90 ° and a relatively weak interaction between the steel tube and the core concrete, a multi-chamber L-shaped steel-concrete tube composite column is proposed, Room-shaped shaped steel pipe, which is poured into concrete. In order to more accurately determine the centroid position of the cross-section of the composite member, the calculation of the centroid of the cross-section of the composite member is given. The calculation method of the slenderness ratio of flexural buckling and the slenderness ratio of flexural-torsional buckling of L-shaped CFST members are discussed. The finite element model of L-shaped column with multi-cell CFST is established. Through the analysis of the calculation results of the stub columns under axial compression, the deformation characteristics and working mechanism of the cross section are analyzed. Through the eigenvalue buckling analysis of its axial compression columns, the deformation characteristics of the components around the two main axes and the corresponding critical elastic force of elastic buckling were compared. Through the nonlinear buckling analysis of the long column, the influence of component length, steel yield strength, initial eccentric direction and other parameters on the mechanical behavior of the member is analyzed. The formula for calculating the stability coefficient of the long column is proposed. The results show that the L-shaped multi-cell CFST column can reduce the deformation of the steel tube at the female corner and increase the confinement effect of the steel tube on the concrete. When the slenderness ratio is small, the flexural and torsional buckling around the symmetry axis plays a controlling role. However, The flexural buckling around the asymmetric axis plays a controlling role when the thinning is larger. Under the condition of one end fixed free end, according to the nonlinear buckling analysis, the compressive bearing capacity in different eccentric directions is not much different. However, The direction of bending the lowest bearing capacity.