双钢管混凝土轴压短柱受力性能研究  

Mechanical behavior of concrete-filled double steel tubular stub columns under axial compression

作　　者：史艳莉[1] 李校孝 王文达[1] 纪孙航 SHI Yanli;LI Xiaoxiao;WANG Wenda;JI Sunhang(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《建筑结构学报》2023年第7期129-141,共13页Journal of Building Structures

基　　金：国家自然科学基金项目(52168020,51768038)。

摘　　要：为研究双钢管混凝土构件轴压性能,完成20根圆形和方形截面双钢管混凝土(CFDT)短柱的轴压试验研究,考察内钢管含钢率、截面形式及外钢管径(宽)厚比对该类构件破坏形态、承载力及延性的影响,同时进行2根钢管混凝土(CFST)轴压短柱的对比试验。试验结果表明:在CFST短柱中内置圆钢管可以显著提高短柱的承载力,且在一定程度上可以避免短柱发生斜剪破坏;CFDT短柱的承载力随着内钢管含钢率和外钢管径(宽)厚比的增大而增加,内钢管相同时,圆形截面CFDT短柱较方形截面CFDT短柱表现出更好的承载能力;两种截面CFDT短柱均展现出良好的延性,圆形和方形截面CFDT短柱峰值荷载点后的荷载平均最大下降幅度分别为2.9%和11.9%。通过有限元软件ABAQUS建立CFDT轴压短柱的数值模型对试验结果进行模拟,模拟荷载-变形曲线与试验结果吻合良好,并基于该模型对典型构件的荷载-变形全过程曲线、相互作用力发展及截面应力分布进行分析,结果表明核心混凝土受到内外钢管的双重约束作用。同时,基于叠加原理和相关规范中CFST短柱轴压承载力的计算公式,对比讨论了两种截面CFDT短柱轴压承载力的计算方法,并提出适用于计算圆、方截面CFDT短柱承载力的简化计算式,该计算式有较好的计算精度。To study the axial compressive performance of concrete-filled double steel tubular(CFDT)stub columns,20 CFDT stub columns with circular and square cross-sections were tested.The factors influencing the failure modes,the capacity and ductility of stub columns were considered,including the ratio of inner steel tube,the cross-section type and the diameter(width)-thickness ratio of the outer steel tube.A comparative test on two concrete-filled steel tubular(CFST)stub columns was also carried out.The tested results show that the capacity of CFST stub columns is improved and the shear failure is also prevented by inserting the circular steel tube in the columns.The capacity of CFDT stub columns improves with increasing the ratio of inner steel tube and the diameter(width)-thickness ratio of outer steel tube.For two CFDT columns with the same inner steel tube,the circular specimens show a better carrying capacity than the square ones.A good ductility behavior is also observed from two CFDT columns.The average maximum decrease on the ultimate capacity of circular and square CFDT stub columns after the peak load is 2.9%and 11.9%,respectively.Then,a numerical model on the CFDT stub columns was established by the finite element software ABAQUS and was utilized to simulate the tested results.A good prediction result is observed from the test and simulated load-deformation curves.The working mechanism of the typical CFDT stub columns was further analyzed,including the load-deformation curve,the distribution of sectional stress,as well as the development of interaction stress.It shows that the inner concrete is subject to the double confinement effect of inner and outer steel tubes.Based on two superposition methods and different formulas for the axial capacity of CFST stub columns,the simplified methods were finally proposed to calculate the axial capacity of CFDT stub columns with circular and square cross-sections,and exhibited a good calculation accuracy.

关 键 词：双钢管混凝土 轴压试验 有限元分析 轴压承载力 

分 类 号：TU398.9[建筑科学—结构工程] TU312.1TU317.1