Hydrodynamic effects on a ground supported structure

Abstract

Liquid storage tanks are used for storing water, inflammable liquids and other chemicals. Thus storage structures are very important for public utility and for industries. Such structures shall be designed for lateral loads such as wind loads/earthquake loads. Earthquake is a sudden movement of the earth caused by the abrupt release of strain that has accumulated over a long time. This dynamic vibration of lateral movement affects structural strength and its behaviour. During the recent past earthquakes, many failures of liquid retaining structures are observed and thus there is a need to understand the behaviour of liquid retaining structures and to consider the latest advances in the design of such structures so that they are not vulnerable under earthquake loads. In the present study, behaviour of a typical ground supported structure under earthquake loads is studied using analytical solutions based on the codes/guidelines prevalent and the same are compared with the detailed dynamic finite element solutions. Both the convective and impulsive mode are captured in the detailed dynamic analysis and the time periods of respective modes of vibration are compared with the available guidelines. Good agreement in results is obtained using the computer based analysis. Behaviour ofliquid storage tanks under earthquake loads has been studied as per Draft code Part II of IS 1893: 2002 [1]. A FEM based computer software is used (SAP2000) for seismic analysis of tank and finally their results are compared.