带约束拉杆L形钢管混凝土短柱偏压试验研究  

Experimental research on eccentrically loaded L-shaped concrete-filled steel tubular stub columns with binding bars

作　　者：蔡健[1] 左志亮[1] 赵小芹[1] 朱昌宏[1] 

机构地区：[1]华南理工大学土木工程系,广东广州510641

出　　处：《建筑结构学报》2011年第2期83-90,共8页Journal of Building Structures

基　　金：国家自然科学基金项目(50878087)

摘　　要：在钢板中部设置具有约束钢板外凸变形作用的水平拉杆,是改善异形钢管混凝土柱力学性能的有效方法。通过8个带约束拉杆L形钢管混凝土偏压短柱试件的试验研究,分析了不同约束拉杆设置、偏心率以及荷载角下带约束拉杆L形钢管混凝土短柱的偏压性能。试验结果表明:约束拉杆延迟了钢管局部屈曲的发生,有助于L形钢管混凝土偏压短柱的承载力和延性的提高;临近或达到极限承载力后近力侧拉杆和钢管对核心混凝土的约束作用明显;偏心受压下该柱的截面应变符合平截面假定。基于带约束拉杆L形钢管内核心混凝土的等效单轴本构关系,利用纤维模型法对试件偏压极限承载力进行计算,计算结果与试验结果吻合良好。利用该数值方法对带约束拉杆L形钢管混凝土短柱的偏压性能进行参数研究。分析结果表明:钢材屈服强度、含钢率越大,N/Nu-M/Mu相关曲线向内收拢;混凝土强度和拉杆约束系数越大,N/Nu-M/Mu相关曲线向外凸出。It is an effective method to set binding bars in the middle of steel plates that can restrain the out of plane deformation of the steel plates to improve the mechanical behavior of special-shaped concrete-filled steel tubular columns.A total of 8 L-shaped concrete-filled steel tubular（L-CFT） stub columns with binding bars were tested under eccentric compression.The influences of the arrangement of the binding bars,load eccentricity ratio and loading angle on the eccentric performance of L-CFT stub columns with binding bars were investigated.Test results indicate that setting binding bars result in the delay of local buckling of the steel tubes and increase of load carrying capacity and ductility of the specimens.Binding bars and steel tubes near the maximum compression side exhibite obvious confinement effects on the core concrete when approaching or reaching the maximum load carrying capacity.The strain distribution of the column section under eccentric compression conform to the assumption that plane section remains plane.The fiber element analysis is adopted to predict the load carrying capacity of the specimens based on the equivalent uniaxial stress-strain relationship for the encased concrete in the L-shaped steel tube with binding bars.The predicted results agree well with the test results.Then parametric analysis using the proposed method is carried out to further study the fundamental behavior of the eccentrically loaded L-CFT stub columns.The analysis results indicate that the N/Nu-M/Mu curves will shrink inward along with increased steel yield strength or sectional steel ratio,while will expand outward along with increased concrete compressive strength or confinement coefficient of binding bars.

关 键 词：L形钢管混凝土 短柱 约束拉杆 偏压 静力试验 力学性能 

分 类 号：TU528.59[建筑科学—建筑技术科学] TU317.1