Analytical Evaluation of Seismic Sloshing Reduction by Suspended Annular Baffle (SAB) in Cylindrical Floating Roof Liquid Storage Tanks

Sloshing has been known as the main cause of seismic damages to floating roof oil tanks in past earthquakes. In a previous study, conducted by the authors, the employment of a Suspended Annular Baffle (SAB) was introduced as a countermeasure for seismic sloshing reduction, and its efficiency was shown through a series of laboratory tests by shake table on a small cylindrical tank subjected to harmonic excitations with various amplitude and frequencies as well as seismic excitations using input earthquakes. In the present study, an analytical formulation has been developed for obtaining the dynamic response of floating roofs, subjected to sloshing, with and without SAB, based on velocity potential function and Lagrange equations of motion. To show the validity of the analytical solution, the results have been compared with those of the laboratory tests. Comparisons show that the presented analytical formulation is in good agreement with experimental study, so that the prediction of the maximum sloshing heights in cases of harmonic and seismic excitations can be done with more than ۹۵% and ۹۰% precision respectively.

Keywords:

Earthquake induced sloshing , Floating roof tanks , Suspended Annular Baffle (SAB) , Shaking table test , Convective damping ratio , Seismic passive control in cylindrical tank , Swirling of the floating roof , Lagrange equations , Velocity potential function