带脱空缺陷的不锈钢管混凝土试件在拉弯作用下的试验研究和有限元模拟

EXPERIMENTAL RESEARCH AND FINITE ELEMENT MODELLING OF CONCRETE-FILLED STAINLESS STEEL TUBES WITH SPHERICAL-CAP GAP SUBJECTED TO ECCENTRIC TENSION

球冠形脱空缺陷已被发现存在于钢管混凝土结构横向构件中,该脱空现象对不锈钢管混凝土拉弯构件的力学性能影响尚未明确,因此完成了8个不锈钢管混凝土试件在拉弯作用下的试验研究,包括4个带球冠形脱空缺陷不锈钢管混凝土试件和4个无脱空不锈钢管混凝土对比试件。试验参数为脱空率和偏心距,通过对比分析试验结果以明晰上述参数对带球冠形脱空缺陷的不锈钢管混凝土试件在偏拉作用下的力学性能影响规律。试验结果表明：在同一脱空率下,试件的承载力随偏心率的增大而减小;在同一偏心率下,试件的承载力随脱空率的增大而减小;偏心率越大,脱空缺陷对试件承载力系数影响越明显。此外,在合理选择不锈钢管与混凝土本构关系的基础上,建立了带缺陷的不锈钢管混凝土拉弯构件的有限元分析模型,计算结果与试验结果吻合良好。

The spherical-cap gap has been found in the transverse members of concrete-filled steel tubular（CFST）.However the effects of the spherical-cap gap on the mechanical properties of concrete-filled stainless steel tube（CFFST） columns is not clear. This paper was based on the experimental study to clear the influence of mechanical properties of CFFST with spherical-cap gap subjected to eccentric tension. And the experiment including 8 CFSST members were tested under eccentric tension in all（4 CFSST members with initial imperfection and 4 counterparts）.The experimental parameters include gap ratio and load eccentricity. The effect law of CFFST columns with sphericalcap gap under eccentric tension was clarified by comparing and analyzing the test results. The test results showed that under the same gap ratio,the bearing capacity of specimen decreased with the increase of eccentricity. And the bearing capacity of specimen decreased with the increase of gap ratio under the same load eccentricity. The greater eccentricity,the more obvious the influence of gap ratio on the bearing capacity coefficient of the specimen. In addition,a finite element model（FEM） was established for the CFSST with spherical-cap gap under eccentric tension. It had a good agreement between FEM and test results.