Seismic response of annular cylindrical tanks

A study is made of the dynamic response of liquid containing, upright annular cylindrical tanks subjected to the horizontal component of a seismic excitation at its base. The tank is assumed to be rigid. Critical response quantities for rigid annular tanks are evaluated over wide ranges of parameters involved and the results presented in a form convenient for use in practical applications. The effect of tank flexibility on the response is then assessed by the procedure proposed by Veletsos and Yang (1977). Simple approximation equations for estimating the fundamental frequency of the outer tank wall-liquid and inner tank wall-liquid systems are proposed.