مدلي براي مخازن هوايي آب با در نظر گرفتن اندركنش ديناميكي سازه و آب در هنگامه زلزله

Dynamic Modeling of Seismic Behavior of Elevated Water Tanks Including Fluid-Structure Interactions

An analytical method has been derived for the fluid surface sloshing phenomenon of cylindrical water tanks. The contained liquid is incompressible and invicid with small amplitude motion. Although sloshing modes of any desired order could be included with the method, here a simplified three degrees of freedom model is applied. It is based on rigid wall structure assumption and thus the hydrodynamic pressure is found. The model is based on the lumped mass concept. Modal analysis method is shear force response history and then the maximum base shears for each. The results are compared with the two-dof Housner model and with the Iranian Earthquake Code (Standard 2800) model. It is shown that the Iranian Code model results are inconservative under certain circumstances or base excitations. Besides, the ,2nd sloching mode has to be taken into account as well if the horizontal load resisting structure deems to be slender. Thus a new proposal for dealing with elevated water tanks in the new Iranian Earthquake Code is presented.