s Rezvantalab - Department of Civil Eng., Faculty of Eng., Urmia University, Urmia, Iran
s Azadi - Department of Civil Eng., Faculty of Eng., Urmia University, Urmia, Iran
s Tariverdilo - Department of Civil Eng., Faculty of Eng., Urmia University, Urmia, Iran
r Shabani - Department of Mechanical Eng., Faculty of Eng., Urmia University, Urmia, Iran

Sloshing due to earthquake induced ground motion could introduce large pressure on the walls of water containing tanks. The natural periods of these tanks are usually between 2 and 15 sec. Therefore, it could be anticipated that for ground motion records rich in these periods the sloshing response of the tanks become violent. This paper compares the response of tanks with different dimension to three types of ground motion records. These include long-period farsource record of Tokachi-oki, near field record of Kobe and far-source record of El Centro. The analysis results show that long-period far-source records could produce large hydrodynamic pressure on tanks wall in the case of coincidence of the excitation frequency with natural frequencies of tank. This show that design spectrum currently in use in the codes could underestimate the lateral force induced on the tanks wall due to sloshing. Also it is shown that while the contribution of higher modes are additive for far field long-period record, these modes have opposite effect in the case of near field and far source ground motions. This could affect the pressure profile along wall height substantially.

Sloshing, long-period, far-source, near-field