摘要
进行共计22根四肢钢管混凝土格构柱的极限承载力试验,试验参数为长细比和偏心率。介绍试验过程和试件的破坏形态,对试件的荷载-挠度曲线、极限承载力及组成构件的受力等进行了分析。试验结果表明,格构柱的柱肢以受压为主,缀管受力较小且处于弹性阶段。近载侧柱肢在试件进入非线性后紧箍效应开始发生作用且不断增大。格构柱破坏时有较明显的面内弯曲,属整体破坏。随着长细比和偏心率的增大,构件整体侧向挠度增大、极限承载力降低。长细比和偏心率对极限承载力的影响基本上是独立的,格构柱总体承载力的折减系数可采用分离的偏心率折减系数和长细比折减系数相乘来计算。研究结果表明,偏心率折减系数可采用与单圆管钢管混凝土偏压柱相似的公式计算;长细比折减系数计算中,换算长细比可应采用简化的放大系数法。
A total of 22 four-tube Concrete Filled Steel Tubular （CFST） laced columns are tested, with the experimental parameters being slenderness ratio and eccentricity. The process of the test and the failure of specimens are presented. The load-deflection curves, ultimate load carrying capacity and behavior of specimen components are analyzed. The test results indicate that compression force is dominant in longitudinal elements, the forces in the lacing tubes are small and the material is in elastic phase. The hoop function of steel tube to the concrete core in longitudinal elements in the load side takes effect and increases after the specimen enter nonlinear phase. The ultimate load carrying capability of specimens decreases with increasing slenderness ratio and eccentricity. The influences of slenderness ratio and eccentricity to ultimate load carrying capability are essentially independent. The global strength reduction of the laced column can be expressed as a product of the dependent reduction factor of slenderness ratio and that of eccentricity. The results indicate that the reduction factor of eccentricity can be calculated by a formula similar to that for a single eccentrically compressed circular CFST column. For the reduction factor of slenderness ratio, equivalent slenderness ratio can be calculated by using a simplified magnified parameter method.
出处
《土木工程学报》
EI
CSCD
北大核心
2007年第6期32-41,共10页
China Civil Engineering Journal
基金
国家自然科学基金(50578042)
关键词
钢管混凝土
格构柱
长细比
偏心率
试验
极限承载力
concrete-filled steel tube （CFST）
laced column
slenderness ratio
eccentricity
test
ultimate load carrying capacity
