不同径厚比下纤维-钢复合管混凝土柱轴压性能

Axial compressive behavior of concrete-filled FRP-steel composite tubular columns with different diameter-thickness ratios

对8个纤维-钢复合管混凝土柱和4个对比钢管混凝土柱进行了轴压试验研究。结果表明,在纤维断裂前,由于受到外部纤维布的约束,纤维-钢复合管混凝土柱的钢管局部屈曲得到了有效抑制,钢管无局部屈曲现象,且内部混凝土的横向膨胀较对比柱减小,纤维-钢复合管混凝土柱的应力-纵向应变关系曲线表现出了纤维与钢复合约束的独特效果,具有钢管屈服后的二次刚度和纤维断裂后显著的残余强度,随着钢管径厚比的不同,纤维断裂后的构件承载力表现出轻微下降、恒定、轻微上升、显著上升的不同趋势。提出了纤维-钢复合管混凝土柱的轴压承载力计算模型,模型计算结果与试验结果显示出较好的一致性。

Eight concrete-filled FRP-steel composite tubular columns and four control concrete-filled steel tubular columns were investigated under axial compression test. Test results show that local buckling of steel tubular is effectively suppressed and no local buckling phenomenon occurs prior to FRP rupture due to the confinement of external FRP jacket,moreover,lateral expansion of inner concrete decreases compared to that of the control column. Stress-strain curves of concrete-filled FRP-steel composite tubular columns exhibit an unique effect as a result of the hybrid of FRP and steel,which display a secondary stiffness after steel yielding and significant residual strength after FRP rupture. With different diameter-thickness ratios,the bearing capacity of concrete-filled FRP-steel composite tubular columns shows various trends,such as a slight descending,constant,slight ascending,or significant ascending. A model to predict the uxial compressive bearing capacity of concrete-filled FRP-steel composite tubular columns was presented,and the predicted values show good agreement with the test results.