EARTHQUAKE BEHAVIOUR OF TOWERS SURROUNDED BY WATER

Abstract

The study deals with the dynamic behaviour of cylindrical tower like structures. Such structures have been approximanted as axisymmetric structures. A parameteric study on the mathematical model of these circular cylindrical towers involving wall thickness and height has been done for different levels of submergence. Two methods of analysis, namely, finite element and beam, have been used. The adequacy of the simple beam method in relation to finite element method has been examined. It has been found that the increase in period of vibration of towers reduces with the decrease in level of submergence and is negligeble when half submerged. Also the increase is more in case of slender towers. The dynamic response of Briones Dam Intake Tower subjected to El-Centro type ground motion has been studied. Study of these results demonstrates that the earthquake response of the tower is increased because of hydrodynamic effects.