seismic behavior evaluation of concrete elevated water tanks

Elevated tanks are important structures in storing vital products, such as petroleum products for cities and industrial facilities, as well as water storage. These structures have various types and are constructed in a way that a greater portion of their weight is concentrated at an elevation much about the base. Damage to these structures during strong ground motions may lead to fire or other hazardous events.  In this  research,  a reinforced concrete elevated water tank, with 900 cubic meters capacity, exposed to three pairs of earthquake records was  analyzed  in time  history using  mechanical  and finite-element  modeling  techniques.  The liquid mass of the tank was modeled as lumped mass known as sloshing mass, or impulsive mass.  The corresponding stiffness constants associated with the lumped mass were determined depending upon the properties of the tank wall and liquid mass. Tank responses including base shear, overturning moment, tank displacement, and sloshing displacement were also calculated.  Obtained results revealed that the system responses are highly influenced by the structural parameters and the earthquake characteristics such as frequency content.