大高宽比刚体模型倾覆反应振动台试验研究

Experimental studies on overturning behaviors of rigid bodies with large aspect ratio under shaking table tests

对于大高宽比基础隔震建筑,倾覆反应是评价其结构安全性的重要指标。为研究大高宽比基础隔震结构的倾覆反应,分别对高宽比为4和5的刚体模型(1/100缩尺)进行了振动台试验,考察其在不同正弦波作用下的倾覆反应。试验研究表明,对于大高宽比刚体模型,将静力倾覆临界加速度(B/H)g作为动荷载作用下模型发生倾覆的判别标准偏于保守,并且刚体模型的倾覆可能性会随着台面峰值加速度agmax的增大而不断减小,随着台面振幅A的增大而逐渐增大。此外,本文在试验研究的基础上,提出了一种根据台面峰值加速度agmax计算模型重心处加速度ai的计算方法。

For the structures with base isolation system, overturning is a critical factor in safety demand. This paper investigates the toppling behavior of rigid bodies with large aspect ratios under sinusoid excitations. Results from the shaking table tests show that theBcritical acceleration of （B/H）g is over-conservative in estimating toppling of rigid bodies with large aspect ratios. It can be found that the Hpossibility of overturning decreases with the rising of peak ground acceleration, while increases with the increasing of the amplitude of ground vibration. Based on the experimental resul ts, a design method for calculating the acceleration of gravity center of rigid bodies according to the peak ground acceleration is presented.