Abstract
This paper describes the vibration characteristics based on measurement data concerning a middle rise building framed by steel. This building is rectangular plan and 43.5 meters height. After completion in March 2004, microtremor measurement is continued periodically in the building. Many data are recorded in two horizontal directions and torsional direction. The content of this study is examination of natural frequency and damping ratio changes along passages with dispersion. And it is studied vibration characteristics of the building in consideration of the underground on earthquake observation data.
