新型格构式钢骨混凝土柱的轴压性能研究

Axial compression behavior of a novel lattice steel reinforced concrete column

提出了一种由格构式钢骨及钢筋混凝土所组成的新型LSRC(latticed-steel-reinforced-concrete,格构式钢骨约束混凝土)柱。通过对4个试件的轴压试验分析,对比CFTEC(con-crete-filled steel tube with encased concrete,外包混凝土的钢管混凝土)柱与LSRC柱的力学性能,探究了不同缀板间距对LSRC柱跨中应变的影响。此外,利用有限元软件对试件建立三维模型,阐述了LSRC柱在压力荷载下的破坏过程和各部件间的相互作用。结果表明:与CFTEC柱相比,由于LSRC柱中的钢筋笼能够有效延缓柱外包混凝土的破坏,其具有更高的承载能力和强重比。同时,LSRC柱对跨中角钢材料的抗压性能利用更为充分,但缀板间距的增大将会降低其跨中外包混凝土的约束作用。此外,利用有限元软件建立的模型能够准确模拟LSRC柱在弹塑性阶段的力学性能,柱中的钢筋笼及内侧角钢均具有良好的约束作用。基于试验和有限元结果,提出了LSRC柱的承载力计算公式,其预测值与有限元结果吻合良好。

This paper investigates the axial compression behavior of a novel lattice steel reinforced concrete(LSRC)column.Four specimens were subjected to axial compression to compare the mechanical properties of LSRC columns and concrete-filled steel tube columns with those of encased concrete(CFTEC columns).The effect of batten plate spacing in LSRC columns on mid-span strain was also investigated.Furthermore,three-dimensional models of the specimens were built in finite element(FE)software to understand the failure processes and interactions between the components of LSRC columns under compression.The results show that LSRC columns have higher bearing capacities and strength-to-weight ratios than CFTEC columns because the embedded reinforcement cages effectively delay the rapid crushing of the concrete covers.Also,the pressure resistance of the mid-span steel angle can be more fully utilized in LSRC columns;however,an increase in batten plate spacing reduces the effects of confinement of the mid-span concrete cover.Furthermore,models built in FE software can accurately simulate the mechanical behavior of LSRC columns in the elastic-plastic phase.The reinforcement cage and inner steel angle have good confining effects.Based on the results of experiments and FE analysis,a formula for calculating the ultimate bearing capacity of LSRC columns is proposed.The predicted ultimate bearing capacities agreed well with the results of FE analysis.