考虑土-结构相互作用的大跨度连续刚构桥振动台阵试验研究

SHAKING TABLES TEST ON A LONG-SPAN RIGID-FRAMED BRIDGE CONSIDERING SOIL-STRUCTURE INTERACTION

土-结构相互作用(SSI)对软土地基上桥梁结构地震响应的影响不可忽略,研究SSI效应对提高桥梁结构抗震安全性十分重要。通过对一座1∶10比例的三跨连续刚构桥模型的振动台阵试验,系统分析了SSI效应对大跨度连续刚构桥地震响应的影响规律。研究表明:SSI效应使振动台台面地震动的峰值和频谱特性发生较大变化;剪切波速和上覆土层厚度是影响SSI效应的重要因素;SSI效应会增大桥梁结构的位移和应变响应,其影响程度与地震动的频谱特性和桥梁结构-地基体系的固有特性密切相关;实时耦联动力子结构试验技术是进行桥梁结构考虑SSI效应的振动台试验的有效方法。

In order to enhance the seismic safety of the bridge, the influence of soil-structure interaction under earthquake excitation should be considered for the bridge-foundation system, especially for the foundation consisting of soft soil. A shaking tables test was performed for a 1 ： 10 scaled model of a three-span rigid-flamed bridge, which systematically investigated the influence of soil-structure interaction on seismic response of the bridge model. The tested results indicate that the peak amplitude and spectrum characteristics of the input ground motion change obviously because of SSI effect. Shear-wave velocity and soil-layer thickness are two important factors affecting SSI effects. The displacement response and strain response of the bridge model are increased when soil-structure interaction is taken into account. The effect varies with the spectrum characteristics of the ground motions and the inherent characteristics of the bridge-foundation system. Meanwhile, the results also verify the effectiveness of the real-time dynamic hybrid testing technique.