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.

To study seismic response of tank, 10 × 10⁴m³ vertical floating-roof tank model is established. The probability relationship between the intensity measure and engineering demand parameters is established based on extensive nonlinear dynamic time-history analysis. Four failure modes of tank were determined, and seismic fragility curve of under each failure mode was obtained. The results show that under frequent earthquake, the exceeding probability of circumferential tensile damage, and instability of tank wall in intact state were 40% and uplift of the bottom sheet was 75%. Under design-based earthquake and rare earthquake, circumferential tensile damage was in intact state, and the exceeding probability of instability were 66.9% in medium damage and 52.9% in severe damage. The exceeding probability of bottom uplift in severe damage is 90%. The method takes the randomness of ground motion into account, which can provide an effective idea for the evaluation of the seismic safety of tank structure.

The present study established a numerical investigation on the behavior of concrete filled steel tube reinforced concrete (CFSTRC) columns under combined loading and two-opposite-side fire. The FEA model was verified by the experimental results of CFST columns subjected to non-uniform fire. The comparison demonstrated an acceptable accuracy for the proposed FEA model. Afterwards, the FEA model was used to analyze the temperature distribution and failure modes of CFSTRC columns subjected to two-opposite-side fire, the influence of fire surface on the fire resistance of the column was also analyzed. The results show that the temperature distribution of the column section is biaxial symmetry, the highest temperature appears at the intersection of the fire surface and the symmetry axis, and the lowest temperature appears at the center of the columns; the load ratios and fire surface have a great influence on the mechanical property of the columns subjected two-opposite-side fire.