Grzeszykowski Bartosz, Szmigiera Elżbieta Danuta
Faculty of Civil Engineering, Warsaw University of Technology, Al. Armii Ludowej 16, 00-637 Warsaw, Poland.
Materials (Basel). 2022 Mar 17;15(6):2231. doi: 10.3390/ma15062231.
A total of 5 steel and 21 rectangular composite concrete-filled steel tube (CFST) columns of moderate slenderness were tested to investigate their ductility under axial compression. The importance of the vertical ductility of columns was discussed, and a novel ductility measure was proposed and utilized to examine the ductility of tested specimens. The analyses showed that the ductility of axially compressed CFST columns highly depends on their failure mode. The key feature influencing the ductility is their ability to dissipate the energy of imposed loads. The larger the volume of a material that may permanently deform and consequently dissipate the energy, the greater this ability. In consequence, the ductility of specimens exhibiting local failure mode was higher in comparison to the columns that underwent global or mixed global-local failure. It was found that both steel and composite columns were able to carry axial loads in the post-critical state; but due to the limitations of local buckling of the steel cross-section in the concrete core and concrete confinement, all tested composite columns showed greater ductility than their steel counterparts.
共对5根中等长细比的钢柱和21根矩形钢管混凝土柱进行了轴向压缩试验，以研究其延性。讨论了柱竖向延性的重要性，并提出了一种新的延性度量方法来检验试验试件的延性。分析表明，轴向受压钢管混凝土柱的延性高度依赖于其破坏模式。影响延性的关键特征是其耗散施加荷载能量的能力。可能发生永久变形从而耗散能量的材料体积越大，这种能力就越强。因此，与经历整体或混合整体-局部破坏的柱相比，呈现局部破坏模式的试件的延性更高。研究发现，钢柱和组合柱在临界后状态下都能够承受轴向荷载；但由于混凝土核心内钢截面局部屈曲和混凝土约束的限制，所有试验组合柱都比钢柱表现出更大的延性。
