Abstract The seismic performance of rounded rectangular hollow tall piers, applied popularly in railway bridges in high-intensity areas in China, has rarely been investigated till now. The current seismic design approaches mostly stem from short-to-medium solid columns whose seismic behavior is different from those of hollow members. According to cyclic tests in publications, there are also obvious differences in the seismic performance between the rounded rectangular hollow piers and the common hollow ones. To clarify the differences among them and update the existing design approach, the damage modes and dynamic responses of rounded rectangular hollow columns under different-level earthquakes should be studied comprehensively. Therefore, three 1/6-scale models from a 40 m prototype pier were tested using a 10.1 m × 8.1 m 6DOFs shaking table. The experimental outcomes were analyzed and compared with those previous semistatic tests. The results showed that the three specimens underwent flexural damage with horizontal cracks distributing along the whole body. Moreover, a second plastic hinge region, evidenced by the denser flexural cracks around the middle part, appeared in addition to the lengthened plastic hinge close to the pier footing. These findings are mainly attributed to the combined influence of the variable hollow section and higher-order effects, which differs greatly from the damage behaviors of specimens under cyclic loads. As expected, the increased stirrup ratio produced great improvement in the seismic performance of rounded rectangular hollow tall piers (DB1 and DB2), while fewer stirrups corresponded to a decrease in ductility (DB3).

中文翻译：

---

基于振动台试验的铁路圆角矩形空心高墩抗震性能

摘要 圆角矩形空心高墩在我国高强度地区铁路桥梁中普遍应用，其抗震性能至今鲜有研究。目前的抗震设计方法大多源于抗震性能与空心构件不同的中短实心柱。根据出版物中的循环试验，圆角矩形空心墩与普通空心墩在抗震性能上也存在明显差异。为了厘清它们之间的差异并更新现有的设计方法，应综合研究圆角矩形空心柱在不同级别地震下的破坏模式和动力响应。因此，使用 10.1 m × 8.1 m 6DOFs 振动台对来自 40 m 原型桥墩的三个 1/6 比例模型进行了测试。对实验结果进行了分析，并与之前的半静态测试进行了比较。结果表明，三个试件均发生弯曲损伤，横向裂纹沿整体分布。此外，除了靠近桥墩基脚的加长塑性铰之外，还出现了第二个塑性铰区域，中间部分周围更密集的弯曲裂缝证明了这一点。这些发现主要归因于可变空心截面和高阶效应的综合影响，这与试样在循环载荷下的损伤行为有很大不同。正如预期的那样，增加的箍筋比率极大地提高了圆角矩形空心高墩（DB1 和 DB2）的抗震性能，而较少的箍筋对应于延性（DB3）的降低。