Overall Seismic Response And Load Effect Combination Calculation And Analysis Of Large LNG Storage Tanks

Due to the complexity of the LNG storage tank structure, it is necessary to analyze the response of the tank under the load effect combination condition. In this paper, based on the ANSYS finite element analysis software, in view of a existing large LNG storage tank, simulation analysis is carried out on the response of all kinds of loads and their effect combinations besides earthquake load. Finally reference for the design of the tank is provided.This paper mainly obtains the following research results:(1)The fine finite element analysis model of large LNG storage tank is established, and the response spectrum analysis method is used to obtain the response of the tank under earthquake conditions. The results show: the top and bottom of the outer tank wall can generate large radial bending moment, which is the key position of the structure design; compared with the vertical earthquake, the horizontal earthquake resulted in a larger displacement of the structure, which shows that the earthquake response of the horizontal earthquake has a main effect on the seismic response of the tank structure;(2)A finite element analysis model is established for the LNG storage tanks,including the outer tank wall, dome, steel reticulated shell structures and the bearing platform. According to the load combination modes specified in the code of our country, the response of the tank under the combination of various load effects is simulated and analyzed. The results show that the dead load of the structure is the control action of all the loads.(3)Two kinds of LNG tank model with and without the steel reticulated shell structures are established, and the response of the models under various load effects is compared and analyzed. Results show: the arrangement of steel reticulated shell structure can increase the ultimate bearing capacity of the tank, but it will generate large bending moment at the connection position of the shell and the tank wall, so the design should be strengthened to prevent the concrete from subjecting to tensile failure; reducing the thickness of the concrete dome could reduce the weight of the structure, but it will also decrease the bearing capacity of structure, thus to determine the thickness of concrete dome needs comprehensive consideration of structural bearing capacity, load response and structure requirements etc.