Damping Ratio of RC Squat Wall with Limited Damage under High-Frequency Earthquake

Abstract

In regions experiencing high-frequency earthquakes, it is necessary to reevaluate the seismic performance of nuclear power plant buildings. In the evaluation of equipment, as well as the structure, the damping ratio of a structure is important. In the present study, to evaluate the damping ratio of walls with limited damage, a shaking table test was conducted for reinforced concrete squat walls with a low aspect ratio. The test variables were the natural frequency of the walls and the type of earthquake (i.e., earthquakes with and without high-frequency contents). The result showed that for a peak ground acceleration of 0.1g, the damping ratio of the walls was 3.5% for the mean and 0.27 for the standard deviation, while for high-frequency earthquakes, the damping ratio was 14.3% lower (3.0% for the mean). In particular, as the dynamic response amplification increased, the damping ratio decreased; when the dynamic amplification was greater than 1.5, the average damping ratio of the walls was 2.4%.