Horizontal storage tanks are integral to the petrochemical industry but pose significant risks during earthquakes, potentially causing severe secondary disasters. Current seismic designs predominantly assume rigid tank walls, which can lead to an underestimation of seismic responses. This study introduces a novel analysis method for assessing the dynamic response of flexible-walled horizontal storage tanks. By separating the liquid velocity potential into convective and impulsive components and integrating these with beam vibration theory, we developed a simplified mechanical model. A parameter analysis and dynamic response research were conducted using numerical methods. Results indicate that flexible tank walls amplify seismic responses, including liquid dynamic pressure peaks, base shear, and overturning bending moments, compared to rigid walls. Additionally, the impact of flexible walls is more pronounced in tanks with larger radii, aspect ratios, diameter–thickness ratios, and H/R ratios. These findings highlight the necessity for revised seismic design approaches that consider wall flexibility to enhance the safety and resilience of horizontal storage tanks.

Consider the swinging effect of spherical tank, the theory of velocity potential is adopted, and a reasonable potential function is derived according to the boundary conditions. Further, the dynamic fluid pressure, the wave height of the liquid, the shear force and the overturning moment at the bottom of the spherical tank is calculated, and a simplified dynamic model of spherical tank considering liquid sloshing and swinging effect was constructed. The seismic response was studied and compared with the results without considering the swing effect. The results show that: for Ι, II site conditions, base shear force and overturning moment of considering the swing effect is slightly smaller than when nonconsidering and the difference rate between the two is very small. III–IV site conditions, each condition value of considering the swing effect is larger than when nonconsidering and the difference rate between the two is relatively large. Aseismic design of spherical tank and the influence of swing effect should be considered if the site condition is III and IV, and if site I and II, they can be ignored.