Analysis of vulnerability curves and surfaces of storage tanks considering vector seismic motion parameters

Storage tanks are key equipment for storing and managing liquids in industrial production. Their seismic performance evaluation is often carried out through the failure probability of vulnerability analysis. However, the vulnerability curve obtained from a single seismic component will increase the uncertainty of the evaluation, and the seismic analysis of large-capacity storage tanks has problems such as complex models and large calculations. Therefore, this paper adopts Edurance Tme Aalysis (ETA) to effectively evaluate the seismic performance of storage tanks, and verifies the effectiveness of this method by performing incremental dynamic analysis on 22 selected near-field seismic waves. Using the idea of ETA, the endurance time and seismic motion parameters are converted to derive the dynamic response of the second seismic motion parameter. Subsequently, scalar fragility curve analysis is performed for the two seismic motion parameters respectively, and then vector fragility surface analysis is performed in combination with these two parameters. The research results show that ETA can approximately determine the ultimate seismic performance of storage tanks through a single dynamic analysis, highlighting its effectiveness and efficiency in the dynamic response evaluation of storage tank structures. The surface morphology under different damage states shows a gradient change, with the surface of slight damage being the steepest and the surface of severe damage being the slowest. Compared with the scalar fragility curve, the vector fragility surface can enhance the reliability of probability and significantly reduce the uncertainty of the danger curve in structural response analysis. The fragility surface can not only be converted into a conventional fragility curve, but also complete the multi-dimensional characteristics of the seismic motion. The research results provide a more comprehensive and accurate quantitative analysis method for the evaluation of the seismic performance of liquid storage tanks.