# Seismic Response of a Large LNG Storage Tank Based on a Shaking Table Test
## 2 Shaking Table Test of Storage Tank Models
### Analysis of Test Results  
#### 2.3.1 Non-Isolated Storage Tanks  
Extracting the peak acceleration measured by the acceleration sensor and drawing the peak acceleration variation curve of the non-isolated storage tank, according to the test direction and height of the acceleration sensor, as shown in Figure 4.  
As shown in Figure 4a, under the action of the seismic wave in the X direction, the Y and Z directions of the storage tank will still produce a certain acceleration response, but the magnitude of the acceleration response in the Y and Z directions is smaller than that in the X direction. As the height increases, the X direction acceleration of the non-isolated storage tank gradually increases. Since the dome is the weakest position, the acceleration at the top of the dome increases sharply, and the acceleration response reaches a peak at the top of the dome. The Y direction and Z direction acceleration responses decrease at the dome position. As the seismic peak acceleration increases, the Y direction acceleration at the top of the cap becomes more and more obvious, and the Z direction acceleration at the position of the center of mass of the storage tank is also more obvious. This phenomenon shows that the top structure of the storage tank cap has a higher strength and good stability, and the Z direction centroid position is the most unfavorable force position on the outer tank wall. As shown in Figure 4b, under the action of the ground motion in the XZ direction, the Y direction of the storage tank will still produce a certain acceleration response, but it is smaller than the X and Z directions, and the Z direction acceleration response is more severe  
Figure 4: Variation law of acceleration response of non-isolated storage tank along height direction: (**a**) Wolong wave (X direction); (**b**) Wolong wave (XZ direction); (**c**) Wolong wave (XYZ direction); (**d**) Artificial wave (XYZ direction). than the X direction. With the increase in the peak seismic acceleration, the acceleration responses in the X, Y and Z directions gradually increase along the height direction, but the acceleration in the Y direction decreases more and more at the top of the bearing platform, and the acceleration in the Z direction increases more and more at the position of the center of mass of the storage tank, and the acceleration at the top of the dome increases sharply, which is also consistent with the seismic response law of the storage tank under the action of the X direction ground motion. As shown in Figure 4c,d, under the action of XYZ three-direction ground motion, the X direction acceleration of the outer tank of the storage tank gradually increases with the increase in height. The acceleration at the top of the dome increases sharply, but decreases when it reaches the top of the dome, and the greater the earthquake intensity, the more obvious the sudden change phenomenon, which is also consistent with the seismic response law of the storage tank under the action of X unidirectional and XZ bidirectional ground motions. The phenomenon also shows the weakness of the dome. When the seismic design of the storage tank is carried out, the position of the dome needs to be reinforced to prevent the damage of the entire LNG storage tank due to the weak dome in practical engineering applications. On the whole, under the action of the X direction, XZ two-direction and XYZ three-direction ground motion, the acceleration response of the Z direction is more severe than that of the X and Y directions, indicating that the tank structure is excited by one-direction, two-direction and three-direction ground motion. When the storage tank is designed, it will have a large vertical (Z direction) acceleration response, and it is necessary to take vertical seismic isolation measures for the storage tank into consideration when designing the storage tank.