Sloshing in concrete cylindrical tanks subjected to earthquake

The behaviour of cylindrical concrete tanks under seismic excitations is studied using the finite-element method. Furthermore, shaking table tests are carried out in order to check the reliability of the numerical model. Time history analysis of different models is performed using data from four major earthquakes. Different principal parameters, such as liquid sloshing, liquid viscosity and wall flexibility, are considered for their effects on tanks' responses. The results provide a value for wall thickness to tank diameter ratio which may be used as a guide in the consideration of wall flexibility effects. For the range of viscosity considered, no significant effect on the amplitude of the sloshing is observed. In addition, it should be emphasised that the consideration of the vertical component of earthquake excitation induces noticeable increases in the axial force of the walls, the liquid pressure and the wall shear forces which may result in cracking of the concrete tank. Finally, comparison is presented between the calculated maximum wave height and some reference established codes, showing the underestimation of superficial wave heights by the Iranian practical code.