Water sloshing of PCS water storage tank (PCSWST) can cause a significant effect on the dynamic response of Shield Building under seismic loads. It is complicated to perform the calculation of water sloshing especially for the tanks with irregular shapes. Consequently, it is important to establish an appropriate equivalent mechanical model for simulation[1], [2].
In this paper, the water sloshing is firstly investigated based on the potential flow theory, which including the seismic modal analysis. Based on the theoretical research, a highly efficient (simplified) calculation formula is derived, which mainly considering the impulse mass, convective mass, position function and spring stiffness etc., through this way the equivalent model for PCSWST is established by applying mass-spring element. The equivalent models based on Housner & Graham theory[3], [4] are also established. Additionally, the 3-D finite element model of water sloshing considering fluid-structure interaction is established by using the software of Ansys.
Total of four models are built as shown in the paper, then modal analysis and dynamic response under earthquake excitation are performed using ANSYS. The results are compared to justify the equivalent model in this paper. The results indicate that Graham formula did not provide the correct location expressions for the convective masses. The expressions for the impulsive mass and its position given by Housner are not satisfactory. As a comparison, the results from the equivalent model, which is recommended in this paper, can best fit the data from finite model. From above results and comparisons, a more reasonable and refined equivalent model for PCSWST design is provided.
Based on the equivalent model established, the influence on structure caused by the increase of water mass is analyzed. The results from the seismic analysis are compared, including member force, shear strain and shear force. Based on the research, the feasibility of the design is analyzed, which can provide important support for the structural design.
Finally, the seismic reduction of water tank is studied using the finite element model established in this paper. The horizontal and vertical anti-sloshing baffles are designed. The maximum acceleration and displacement corresponding to different baffle length are compared to study the effect of the seismic reduction.
