08-10-2014, 04:03 PM
Elevated water tanks have filled during past earthquakes owing to large torsional response. Considerable torsional response may occur due to accidental eccentricity if the uncoupled torsional and lateral natural periods of the tanks are closely spaced. Torsional response of RC elevated water tanks supported on axisymmetric frame-type stagings has been studied in this thesis. Such stagings are idealized as one-storey lateral-torsional coupled systems consisting of two or four lateral force resisting elements, depending on the lateral-to-torsional stiffness ratio and lateral-to-torsional strength ratio of the staging. Linear and non-linear responses of these systems are studied due to earthquake ground motions. This study focuses attention on the maximum element displacement. Between two systems having the same lateral and torsional natural periods, normalized eccentricity and modal damping, the one with a lower torsional-to-lateral stiffness ratio, i.e., tanks with small number of panels and columns, undergoes a larger torsional response. Also, in the elastic range the e