为了提升中空夹层钢管混凝土短柱的轴压性能,本文提出并设计了薄壁方套方中空夹层多腔钢管混凝土短柱(MCFDST),对其轴压力学性能进行了试验研究。试验试件包括15个MCFDST短柱试件和3个方套方中空夹层钢管混凝土短柱(CFDST)试件。以混凝土抗压强度、外钢管宽厚比、空心率和是否设置拉肋为参数,通过分析试件的变形、荷载-位移曲线、破坏现象和延性系数,探究了各参数对试件的极限承载力、失效模式和延性的影响。试验结果显示：混凝土抗压强度从58MPa提升至90MPa,试件承载力提升46%,延性系数最高降低74%；外钢管宽厚比从39降低到29,试件承载力提升12.5%,延性系数明显增大；空心率从0.31增大到0.38,试件承载力提升了1.3%,延性系数仅提升1%；增设拉肋使构件承载力提升14.2%,延性系数最高提升282%。其次,利用试验数据验证了数值建模方法的有效性和模型的正确性,并开展了大量有限元参数分析,讨论了现行规范对该短柱轴压承载力的适用性,发现日本规范AIJ的预测公式可以精确估计MCFDST短柱轴压承载力。

To improve the axial performance of concrete-filled double-skin steel tubular (CFDST) stub columns, a novel thin-walled multi-cavity concrete-filled double-skin tubular (MCFDST) stub column is proposed and experimental investigations are performed to study the axial compressive behavior of MCFDST stub columns. Fifteen MCFDST stub columns and three CFDST stub columns are designed and fabricated. Four parameters considered in this study include concrete compressive strength (CCS), width-to-thickness ratio (WTR) of outer tube, hollow ratio (HR), and the presence of tension ribs. By analyzing the deformation, load-displacement curve, damage phenomenon,and ductility coefficient of stub columns, the ultimate bearing capacity,failure mode, and ductility performance are examined. The experimental results show that the bearing capacity increases by 46% while the ductility coefficient decreases by 74% when the CCS increases from 58 to 90 MPa. As the WTR decreases from 77 to 58, the bearing capacity increases by 12.5% and the ductility coefficient also increases obviously. The bearing capacity and ductility coefficient increase by only 1.3% and 1.0%,respectively,when the HR increases from 0.31 to 0.38. Significantly,the presence of tensile ribs increases the bearing capacity and ductility coefficient by 14.2% and 282%, respectively. Moreover, the effectiveness of numerical modeling method and the correctness of numerical model are verified using experimental data, and many finite element parameter analyses are carried out. The applicability of design methods in current specifications to the axial bearing capacity of this MCFDST stub column is discussed, indicating that the prediction formula in Japanese standard AIJ is suitable to estimate the axial compressive bearing capacity of MCFDST stub column.

TU 398.9

四川省青年科技创新团队项目(2019JDTD0017)；中国博士后科学基金(2022M722639)；四川省自然科学基金(2023NSFSC0889)