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In this article, a laboratory investigation on prestressed composite steel cylindrical tanks is performed at different prestressing parameter values (coil span, thickness, and prestressing force). Natural vibration frequencies of a traditional tank and a prestressed composite tank were determined at different filling levels. The research results reveal that prestressing using a steel wire strand has a positive effect in terms of the value of the attenuation coefficient where, when comparing a traditional tank with a coiled tank with a coil span equal to a = 3d, the attenuation coefficient changes in a positive direction by 22.9%; whereas, when comparing a traditional tank with that with a coil span equal to a = d, then the positive effect reaches up to 33%. The value of the attenuation coefficient of a half-filled tank shows that prestressing improves the attenuation coefficient at a coil span equal to a = 3d and up to 8.7%, and with a coil span equal to a = d, up to 26%. Conversely, in the analyses of the tank specimen filled up to the maximum level, the attenuation coefficient changes in a positive direction with a coil span equal to a = 3d, up to 15%, and when accounting for a coil span equal to a = d, up to 35%. In general, the effect of the use of prestressing in terms of the attenuation coefficient shows a positive trend between a percentage range of 8.7 and 35%, depending on the liquid filling conditions, and the vibration amplitudes decrease in a percentage range of 3.8–20%, also depending on the coil span and filling conditions of the tank. The obtained laboratory results positively expand the investigations performed within this research field. As a result, the corresponding findings can be used for the construction and design phases of vertical steel cylindrical tanks. |
