Abstract
The objective of this paper is to assess the effects of initial irregularities on the seismic response of cylindrical tanks. Such out-of-roundness induces hydrodynamic pressure components which are circumferential high order modes and neglected in current design assumptions. Seismic response formulas are derived for cylindrical tanks having arbitrary initial irregularities from Lagrange's kinematic equation using natural frequencies, vibration modes and the hydrodynamic pressure. The hydrodynamic pressure in an irregular tank is evaluated by using velocity potential function. Natural frequency analysis is done by means of the transfer matrix method taking into concideration the initial hoop stress.
The effect of ratio H/D (H: liquid height and D: tank diameter)and shape of initial irregularities are examined by numerical calculations.
