土-结构动力相互作用对上部结构反应的影响:1/4大比例钢框架模型试验研究及其数值模型验证(英文)

Experimental investigation of soil-structure interaction effects on structures through ambient vibration tests on a 1/4 scaled steel-frame structure model

为更好地了解评估土-结构动力相互作用(SSI)对上部结构的反应影响,在1/4大比例7层钢框架模型上进行一系列常时微动试验。在模型上与自由场地面安装21通道加速度传感器记录微动测试中结构水平、摇摆及弹性变形。通过不同微动输入-输出组,在频域和时域中验证并获得柔性地基,拟柔性地基及固基条件下结构传递函数及有效频率。试验结果表明结构物在微动试验情况下两主轴方向SSI效应皆为显著,主要表征周期延长(10%～22%),此显著SSI效应可归因于两正交向卓越摇摆模态。采用Veletsos等提出单自由度SSI分析模型进行参数识别并与试验数据进行比较,结果表明此模型能较好预测结构微动激励下动力反应。

The effects of soil-structure interaction （SSI） on the response of a structure are examined and interpreted through a series of ambient vibration tests （AVT） on a seven-storey,1/4 scaled steel-frame structure model constructed in the Center for Integrated Protection Research of Engineering Structures （CIPRES）,Hunan University. Totally twenty-one digital accelerometers are installed within the building structure and on the ground level in the proximity of the model in order to record the translational,rocking and elastic responses of the structure during AVT. With different input-output vibration data pairs,transfer functions of the structure,together with the effective frequencies under flexible-base,pseudo flexible-base and base-fixed conditions are derived and identified in time-frequency domain. The experimental results indicate that the SSI phenomena of the structure model during AVT are remarkable in both transverse and longitudinal directions,in terms of significant period lengthening （ranging from 10% to 22%）. This phenomenon could be generally attributed to the significant rocking modes in both directions during vibration. In addition,a well-established SSI numerical model originated by Veletsos is adopted to calculate the test data,and the numerical simulation results are in agreement with the test results,indicating that the adopted mathematical model can reasonably predict the responses of structures to ambient vibrations.