CFRP包裹带脱空缺陷圆CFST短柱的偏压受力性能

Eccentric compressive behavior of CFRP wrapped circular CFST stub columns with initial concrete imperfection

为了获悉碳纤维增强复合材料(carbon fiber reinforced polymer,CFRP)条带对带脱空缺陷圆钢管混凝土(concrete filled steel tube,CFST)短柱的修复加固作用,文章通过ABAQUS软件建立了偏压下CFRP包裹带脱空缺陷圆CFST短柱的数值分析模型,并通过现有试验数据验证了模型的准确性,进而分析了偏心率、钢材强度、混凝土强度、径厚比、CFRP强度、CFRP包裹层数及脱空比等关键参数对偏压构件承载力、破坏模式等基本力学指标的影响规律。研究结果表明:偏压下CFRP包裹带脱空缺陷圆CFST短柱的主要破坏模式包括钢管屈曲、CFRP断裂及混凝土压溃;CFRP条带包裹可以明显提高带脱空缺陷CFST短柱的承载力和延性;构件偏压极限承载力随着钢材强度、混凝土强度及CFRP包裹层数的增加而提高,随着脱空比、径厚比及偏心率的提高而降低。研究结果可为CFRP包裹带脱空缺陷圆CFST柱的设计和应用提供科学依据。

In order to learn the repair and reinforcement performance of carbon fiber reinforced polymer(CFRP)wraps on the circular concrete filled steel tube(CFST)stub columns with initial concrete imperfection,the numerical analysis model of CFRP wrapped circular CFST stub columns with initial concrete imperfection under eccentric compression was established by ABAQUS software,and verified by the existing test data.The influence of key parameters such as the load eccentricity,steel strength,concrete strength,diameter-to-thickness ratio,CFRP strength,number of CFRP layer and ratio of concrete gap on the basic mechanical indexes such as bearing capacity and failure mode was analyzed.The results show that the major failure modes of CFRP wrapped circular CFST stub columns with initial concrete imperfection included steel tube buckling,CFRP fracture and concrete crushing.The ductility and the eccentric compressive resistance of this type of composite columns can be improved by CFRP wrapping.The eccentric compressive resistance increased with the increase of steel strength,concrete strength and number of CFRP layer,but decreased with the increase of gap ratio,diameter-to-thickness ratio and load eccentricity.The research results would provide a scientific basis for the design and application of CFRP wrapped CFST columns with initial concrete imperfection.