| 英文摘要 |
The building structures are subjected to both horizontal and vertical ground motions during earthquakes, but only the horizontal ground motion has been extensively studied and considered. Most of the prevailing seismic codes assume the vertical component of the ground motion to be 1/2 to 2/3 of the horizontal component. However, it was found that the vertical ground motion may equal or even significantly exceed the horizontal ground motion in recent earthquakes. In such situations, most existing code specifications must be considered un-conservative.
In order to understand the building responses from vertical ground motions, many earthquakes records are studied in this paper. System identification methods (ARX Model) are used to analyze the strong motions and to find out the characteristics of the vertical amplification factors and the natural frequencies of buildings. The results show that the vertical amplification factors for high-rise buildings and low-rise building are 1.78 and 2.52 respectively, and the average vertical amplification factor of all buildings is about 2. The result points to an important message, the taller the building is, the greater the effect of vertical vibration on the building will be. |
