In order to study the compression behavior of rectangular steel reinforced concrete columns with built-in steel tubes under different eccentric loads, three 1/10 scale specimens were designed and monotonic loading tests were carried out on them. The dimensions, steel bars and steel tube of the three specimens were the same except for the location of the loading point. The eccentricity ratios of the three specimens were 0, 0.25 and 0.5, respectively. The failure modes, load-bearing capacity and displacement characteristics of the test specimens were analyzed. According to the Chinese code, the load-bearing capacity calculation principles and methods of steel reinforced concrete columns with built-in steel tube were investigated for the comparison. The study shows that the peak vertical loads of specimens decrease and the corresponding vertical and horizontal peak displacement increase as the eccentricity increases. The load-bearing capacity calculation results from Chinese code are slightly smaller than the test result because of the unconsidered sleeve effect of the internal steel tube. The errors between them are small, and the calculation methods are beneficial to ensure the structural safety.

中文翻译：

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钢管内置钢筋混凝土柱的受压性能研究

为了研究矩形钢管混凝土内置钢管在不同偏心荷载下的受压性能，设计了三个1/10比例的试件，并对它们进行了单调荷载试验。除加载点的位置外，三个试样的尺寸，钢筋和钢管均相同。三个样品的偏心率分别为0、0.25和0.5。分析了试件的破坏模式，承载力和位移特性。根据中文规范，研究了钢管内置钢筋混凝土柱的承载力计算原理和方法，以进行比较。研究表明，随着偏心率的增加，试样的峰值垂直载荷减小，相应的垂直和水平峰值位移增大。由于未考虑内部钢管的套筒效应，中文规范中的承载力计算结果略小于测试结果。它们之间的误差很小，计算方法有利于保证结构安全。