Lightweight bolted storage tank design: Experimental and numerical modal analysis

Abstract

This paper presents experimental and numerical investigations of the modal behavior of bolted storage tanks, including both filled and empty states. Structures with low natural frequencies are especially vulnerable to dynamic excitations, as they can resonate with vortex shedding at critical wind speeds or with the predominant frequencies of seismic events, leading to amplified vibrations. To address these effects, a coupled numerical model that consistently represents fluid-structure interaction is presented and rigorously validated against experimental measurements on a real bolted tank with non-standard anchoring. After validation, this model is employed to analyze the effects of anchor bolt configuration, tank wall thickness, and fluid density on modal characteristics of the structure.The findings show that the appropriate anchoring conditions enable a reduction in tank wall thickness without compromising the first three natural frequencies, offering practical guidelines for the design of lightweight bolted tanks.