Reversed cyclic loading tests of two circular hollow RC piers were conducted in this study to investigate the effect of different amounts of inner and outer circular hoops on their flexural behavior. The test results showed that the column with a smaller amount of inner circular hoops presented better flexural response than the as-built column with an equal amount of inner and outer circular hoops. Also, the demand developed on the inner circular hoops was smaller than the outer one within the plastic hinge regions, which verified that using a smaller amount of inner circular hoops was reasonable and effective. By examining the confining stress experienced by the concrete in the radial and circumferential directions based on a detailed theoretical analysis, a modeling approach was proposed to take the confinement effect in circular hollow RC piers into consideration. The proposed modeling approach was validated through comparisons with the experimental study and satisfactory agreement was found.

中文翻译：

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减少内箍数量的圆形空心钢筋混凝土桥墩的抗弯性能

本研究对两个圆形空心钢筋混凝土桥墩进行了反向循环加载试验，以研究不同数量的内外圆箍对其弯曲行为的影响。试验结果表明，内环箍数量较少的柱比内、外环箍等量的竣工柱表现出更好的弯曲响应。此外，在塑性铰区域内，对内环箍开发的需求小于外环箍，这证明使用较少数量的内环箍是合理和有效的。通过在详细的理论分析的基础上检查混凝土在径向和圆周方向上所承受的围压，提出了一种建模方法来考虑圆形空心钢筋混凝土桥墩的约束效应。通过与实验研究的比较验证了所提出的建模方法，并发现了令人满意的一致性。