Abstract
This paper presents the evaluation of first mode damping ratios, the changes along passages, and amplitude dependence for a middle-rise steel framed building based on measurement data. The building is 50 m height. It is rectangular plan and many data are simultaneously collected in two horizontal directions at optional points on the top floor. By using random decrement technique, first mode damping ratios are calculated. It is clarified characteristics of the changes along passages of first mode damping ratios based on microtremor measurement, and amplitude dependence based on strong wind and earthquake measurement.
