摘要
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。
As L-shaped concrete filled steel tubular columns have steel plates of 90° negative angle,the interaction between the steel tube and the core concrete is relatively weak.In order to overcome this shortcoming,the multi-cell composite L-shaped concrete filled steel tubular column,was proposed.It is made by welding three commercially available rectangular steel tubes to form a multi-cell L-shaped steel tube and pouring the concrete in it.To determine the centroid position of the member section more accurately,a calculation procedure of determining the center of section with the method of section stiffness conversion is given in this paper.Calculation motheds were discussed for computing the flexural buckling slenderness ratio and the converted flexural-torsional buckling slenderness ratio of L-shaped concrete filled steel tubular columns.The finite element models for the simulation study were established.Through the analysis of the calculation results of the short columns under axial compression,the deformation characteristics and working mechanism of the sections were investigated.The deformation characteristics and the corresponding elastic buckling critical force about the two main axis were compared through the characteristic value buckling analysis of the long columns under axial compression.And the influence of parameters,such as the length of columns,yield strength of steel,direction of initial eccentricity,on the bearing capacity of the column was studied though the nonlinear buckling analysis of long columns.A formula for calculating the buckling coefficient was also put forward.The results show that the multi-cell composite L-shaped concrete filled steel tubular columns can reduce the deformation of steel tube at the inner corners of the section.The interaction between the steel tube and the core concrete can be increased.As the slenderness ratio is relatively small,the flexural-torsional buckling around the symmetry axis is critical.But the flexural buckling has a controlling effect as the slenderness ratio is relatively large.When one end of column is fixed and the other is free,the compression capacity with different direction of eccentric loading is not significantly different from the results of non-linear buckling analysis.However,the one around the nonsymmetry axis has the minimum capacity.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2013年第S1期306-313,共8页
Journal of Building Structures
基金
国家自然科学基金项目(51278019)
关键词
钢管混凝土L形截面柱
多室式
轴压
有限元分析
concrete filled steel tube column with L-shaped section
multi-cell type
axial compression
FEA
