碳纤维增强方钢管混凝土压弯构件的静力性能(Ⅱ)——机理分析与承载力

应用ABAQUS软件对碳纤维增强方钢管混凝土(S-CF-CFRP-ST)压弯构件的工作机理进行分析,分析结果表明:随着荷载的增加,S-CF-CFRP-ST压弯构件从全截面受压到部分截面受拉;钢管在柱中截面首先屈服,然后向端板发展;横向受拉的CFRP对试件起到了很好的约束作用。钢管与核心混凝土的相互作用力沿纵向在试件中截面最大,向两端部逐渐减小;沿截面边长在转角处最大,向中点逐渐减小。黏结强度对试件弹性阶段的刚度、承载力及钢管与混凝土之间的相互作用力影响不大。不同加载路径对试件静力性能的影响也不显著。提出了S-CF-CFRP-ST压弯构件的承载力相关方程,计算结果与试验结果吻合良好。

STATIC PERFORMANCE OF CONCRETE FILLED SQUARE STEEL TUBULAR BEAM-COLUMN STRENGTHENED BY CFRP EXTERNALLY(Ⅱ) :MECHANISM ANALYSIS AND LOAD CARRYING CAPACITY

The mechanism of the concrete filled square steel tubular beam-columns strengthened by CFRP externally(S-CF-CFRP-ST) were analyzed by using ABAQUS software,and the results showed that the compressive region on cross-section varied from compression on the whole cross-section to tension on partial cross-section with loading increase.The steel tube yielded firstly on the cross-section at mid-height,and then the yielding propagated toward the end plates.The transverse CFRP in tension provided effective confinement on the specimens.The interaction force between the steel tube and the concrete reached its maximum value on the cross-section at mid-height,and it decreases when the distance to the end plates became smaller.On the cross-section,the interaction force had its maximum value at the corner while it decreased when the position moved to the mid-point of the tube side.The adhesive strength between the steel tube and the concrete had little effect on the load carrying capacity,and on the elastic stiffness of the specimens as well as on the interaction force between the steel tube and the concrete.The static behavior of the members was not sensitive to the different loading routes.Equation for calculating the loading carrying capacity of the composite columns was presented,and the estimated results agreed well with the experimental results.