圆钢管约束高强混凝土轴压短柱的试验研究与承载力分析

Axial compression test and analysis of circular tube confined HSC stub columns

进行6组共18个圆钢管约束高强混凝土短柱在循环或单调轴压荷载作用下的试验研究。试验中的主要参数为混凝土强度(fcu=88.14～94.17)和钢管径厚比(D/t=21.62～43.01)。试验结果表明,圆钢管约束高强混凝土短柱的轴压承载力高于同条件的普通钢管混凝土构件,但两种构件的延性无显著差异;随钢管中纵向应力的降低,构件的轴压承载力提高。对构件的应力分析结果表明,圆钢管约束高强混凝土轴压短柱的峰值荷载点对应于钢管的屈服点。在应力分析结果的基础上建立圆钢管约束混凝土的轴压承载力公式,公式结果与试验结果吻合较好。基于试验结果对Mander约束混凝土模型进行修正,使模型适合于约束高强混凝土。

A total of 18 circular tube confined high strength concrete （HSC） stub columns were tested under or monotonic axial 88.14～94.17 MPa） compression. The parameters in the study include the compressive strength of concrete cyclic （fcu= and diameter-to-thickness ratio of the steel tube （D/t=21.62-43.01）. The experimental results indicate that the axial bearing capacity of a steel tube confined concrete stub column is greater than that of a CFT column with equivalent parameters, while difference in ductility is insignificant. The axial bearing capacity of the columns increases as the longitudinal stress of the steel tube decreases. The results of elasto-plastic analysis of the steel tube indicate that the steel yields at the peak load. A design equation is proposed to calculate the axial bearing capacity of circular tube confined concrete columns. The results from the proposed equation for stub columns are consistent with the test resuhs. A modified Mander＇s model that is suitable for confined HSC is proposed based on the test results.