CFRP约束圆钢管高强混凝土短柱轴压试验研究

Experimental Study on Axial Compression Behavior of CFRP-High Strength Concrete Filled Circular Steel Tube Short Columns

为研究混凝土强度、径厚比、CFRP(碳纤维增强复合材料)层数及CFRP包裹方式等参数对CFRP约束圆钢管混凝土轴压静力性能的影响,进行了6个圆钢管混凝土短柱和18个CFRP-钢管混凝土短柱的轴压对比试验.研究发现CFRP的约束对圆钢管混凝土承载力有较显著的提升,且承载力的提高幅度随着CFRP的增加而增加.钢管高强、超高强混凝土短柱的破坏形态呈现为剪切破坏,延性较差,CFRP的约束可以改善其延性,且CFRP层数越多延性越好.半包CFRP试件性能接近于全包CFRP试件性能.随径厚比增大,CFRP约束效果下降.若黏结良好,试件失效前,CFRP与钢管能保持协同工作;最后选取了3个经典的CFRP约束钢管混凝土轴压承载力公式进行验算,发现基于CFRP和钢管双重约束的公式能较好地预测其承载力.

In order to study the effects of concrete strength,diameter-to-thickness ratio,CFRP(carbon fiber reinforced composite)layer number and CFRP cladding mode on the axial compression behavior of CFRP confined concrete-filled circular steel tube,the axial compression comparison tests of 6 concrete-filled circular steel tube short columns and 18 CFRP-concrete-filled steel tube short columns were carried out.It is found that the CFRP constraint significantly increases the bearing capacity of concrete-filled circular steel tubes,and the increasing range of the bearing capacity increases with the increase of CFRP layers.The failure pattern of high strength and ultra-high strength concrete-filled steel tube short column is shear failure with poor ductility.CFRP constraint can improve its ductility,and more CFRP layers result in better ductility.The performance of half-packaged CFRP specimens is close to that of full-packaged CFRP specimens.CFRP binding effect decreases with the increasing diameter-thickness ratio.If the bond is good,CFRP and steel tube can work together before the specimen fails.Finally,three classical formulas of axial bearing capacity of CFRP confined CFST are selected for calculation,and the formula based on the double restraint formula of CFRP and steel tube can better predict its bearing capacity.