Earthquake duration has an important effect on the cumulative failure of structures and is an important index to evaluate the earthquake failure potential. Liquid storage tank is a typical thin-walled structure, which is easily destroyed in an earthquake.
Considering the nonlinear shell-liquid coupling and the sloshing mechanical behavior of the liquid free surface, the three-dimensional numerical calculation models of the nonisolated and isolated liquid storage tanks were established, and long and short time duration seismic records with different duration characteristics were selected. The influence of the duration indexes on the liquid sloshing wave height, hoop stress, axial stress, effective stress, liquid pressure and other important dynamic responses was studied.
The liquid sloshing wave height cannot be effectively reduced under long and short duration earthquakes, and the sloshing wave height under a long duration earthquake is generally at least two times larger than that under a short duration earthquake. The tank wall stress is larger under a long-duration earthquake, and wall stresses corresponding to TS(70%) and TS(90%) are close. It is necessary to use a long-duration earthquake to carry out seismic design of a liquid storage tank, and it is recommended to use the significant duration index TS(90%) with high stability, so as to ensure the seismic safety of liquid storage tank.
This study fills the research gap regarding the impact of seismic duration indexes on liquid storage tanks. By establishing 3D numerical models and analyzing multiple duration definitions, it reveals that long-duration earthquakes significantly amplify dynamic responses, and highlights the limited effectiveness of isolation in reducing sloshing wave height. The findings recommend using the stable significant duration index for seismic design, providing practical guidance for enhancing tank safety under prolonged seismic events.
