Abstract
Water supply facility is one of the important lifelines essential to human life. So, stable maintenance of water supply function at the time of major earthquake is strongly required socially. Many damages occurred in the water supply facilities by the 2011 off the Pacific coast of Tohoku Earthquake. Consequently, suspension of water supply lasted to a long term. And many of the water supply facilities were constructed during the high-growth era, or in 1960s and 1970s. From such a background, we have studied on the seismic response of large underground purification reservoir by three- dimensional dynamic analysis with the goal of improvement of accuracy and reliability of seismic performance verification method for water supply facilities. As a result, it has been cleared that the stresses induced by earthquake motion will concentrate on the portion of change of shape and rigidity of the structure, and the top of pillar within the purification reservoir. When the ground around the reservoir was softer than a hard case, the displacement by earthquake motion decreased, but the seismic stress by earthquake motion increased.
