L形加肋钢管混凝土短柱轴压力学性能研究

为考察不同加肋形式对L形钢管混凝土轴压力学性能的影响,共设计8根钢管混凝土轴压短柱试件(2根无肋,6根加肋),进行加压试验,并对比所有试件受压后的截面破坏模态、屈曲形态和位置以及荷载-纵向应变关系曲线,通过ABAQUS有限元软件进行仿真建模,并结合有限元计算轴压全过程曲线、钢管与混凝土的相互作用力分布以及钢管截面上的应力云图纵向分布情况对不同加肋形式构件进行轴压工作机理分析。结果表明:钢管外壁鼓曲、焊缝开裂是8根L形钢管混凝土轴压试验构件在破坏时的普遍表现;布置纵向加劲肋能显著提高试件的极限承载力和延性;对于间断加肋试件,减小其肋间间距可显著提升试件的约束效果;设置在阴角处的加劲肋对提升试件受压性能的效果不明显;钢管对混凝土的约束在无肋试件中主要集中在角部,加肋试件的约束主要集中在肋与角部处;综合考虑焊缝数量、加劲肋面积以及加肋后效果,L-WR-5的加肋方式最优。

Behavior of Concrete Filled L-shaped Stiffened Steel Tubular Stub Columns under Axial Compression

With the purpose of exploring the influence of different forms of L-shaped steel tubes on the axial compression working mechanics,eight concrete-filled steel tubular(CFST)specimens(two without ribs and six with ribs)were designed for an axial compression test.The failure modes,buckling shape and position of specimens,load-longitudinal strain curves were compared.Combined with the results calculated by finite element method(FEM)software ABAQUS,the calculated load-longitudinal strain curves,longitudinal stress distribution of steel tube,and the interaction between steel tube and concrete were used to study the axial compression mechanism of different stiffened form specimens.The results show that the failure modes of all L-shaped concrete-filled steel tube columns are steel buckling and weld cracking.The design of longitudinal stiffening ribs can significantly improve the ultimate bearing capacity and ductility of the specimens.For discontinuous stiffened specimens,the larger the spacing between ribs,the worse the constraint effect is.The effect of adding stiffening ribs at the reentrant corner on the compressive performance of the specimen is not obvious.The restraint effect of the specimens without ribs is mainly concentrated in the steel tube corners,but the restraint effect of stiffened specimens is mainly concentrated in the steel tube corners and the places where ribs were welded.Considering the number of welds,the size of stiffening ribs and the ribbed effect,the L-WR-5 stiffened method is optimal.