Approximate method of estimating seismic performance of high-rise buildings with oil-dampers

摘要

When subjected to long-period ground motions, many existing high-rise buildings constructed on plains with soft, deep sediment layers experience severe lateral deflection, caused by the resonance between the long-period natural frequency of the building and the long-period ground motions, even if they are far from the epicenter. This was the case for a number of buildings in Tokyo, Nagoya, and Osaka affected by the ground motions produced by the 2011 off the Pacific coast of Tohoku earthquake in Japan. Oil-dampers are commonly used to improve the seismic performance of existing high-rise buildings subjected to long-period ground motion. This paper proposes a simple but accurate analytical method of predicting the seismic performance of high-rise buildings retrofitted with oil-dampers installed inside and/or outside of the frames. The method extends the authors' previous one-dimensional theory to a more general method that is applicable to buildings with internal and external oil-dampers installed in an arbitrary story. The accuracy of the proposed method is demonstrated through numerical calculations using a model of a high-rise building with and without internal and external oil-dampers. The proposed method is effective in the preliminary stages of improving the seismic performance of high-rise buildings.