Abstract
This paper presents the evaluation of first mode damping ratios and amplitude dependence for high and middle rise steel buildings based on measuring data. The high-rise building is 120 m height and the middle is 50 m height. They are rectangular plan and many data are simultaneously collected in two horizontal directions at optional points on the top floor. The calculation method of first mode damping ratio is random decrement technique. It is clarified characteristics of first mode damping ratios based on microtremor measurement, and amplitude dependence based on man power exciting, strong wind, and earthquake measurement.
