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It has been predicted recently that the Nankai Trough Earthquake will cause extreme ground motion. The earthquake brings possibility of great damaging the existing super tall buildings in the metropolitan cities of Japan. As a mitigating strategy, seismic retrofitting using damper is commonly used to improve the structural performance of the existing super tall buildings against the earthquake. Frequently, installation of dampers is restricted by the existing building configuration, and an effective design method for this matter has not been studied extensively. Furthermore, when using oil dampers for retrofitting, there may be the cases that sufficient damping effect cannot be obtained in terms of displacement control. The authors address the above-mentioned issues by proposing a design method to determine optimal damper arrangement and investigating the application of displacement controller (gap brace) which exhibits rigidity after a certain displacement. A member-to-member model of an existing super tall building was used in this study. Finally, a design method was proposed using the combination of oil dampers and gap braces.

In order to study effectiveness of dampers in the super-tall buildings subjected to long-period and long-duration earthquake, four types of full-scale dampers typically used in Japan are examined by the long-duration harmonic loading tests. The test specimens are the so-called oil damper, viscous damper, viscoelastic damper, and steel damper, respectively. Different behavior and variations in their dynamic properties are observed, and they are summarized by referring to distinct materials and mechanisms of the dampers. The viscous and viscoelastic dampers show relatively large variations in the dynamic properties, and simplified evaluation rules to predict the peak cyclic force variations for the dampers are proposed.

The number of the seismic isolated high-rise building has been gradually increasing in Japan. However, the full-scale researches about the wind-induced response of seismic isolated high-rise building are not sufficient. The wind resistant design of the building is done so that the primary members become the elastic-region even if the strong wind forces are acted. Thus far a long-term monitoring to wind velocity and response of 20-story seismic isolated high-rise building with an elongated section has been executed. This paper discusses the characteristics of wind-induced response for this seismic isolated high-rise building using the monitoring records. Main focus of this paper is torsional components of response. Measured data show torsional response affects evaluation of habitability

This paper discusses the properties of viscoelastic damper during long duration random vibration. In this study, the long duration model of viscoelastic constitutive rule, which is based on fractional time-derivative model & capable for heat transfer analysis, is used to evaluate viscoelastic damper properties such as temperature dependence, stiffness etc. Analytical results show that temperature inside the viscoelastic material body become stable by effect of heat conduction & heat transfer even if the damper is vibrating randomly. In addition, this paper proposes a simplified evaluation method using sinusoidal-wave to substitute random time history data properties. Accuracy of proposed evaluation method is validated by comparing with analysis result using random time history data.

Continuous structural health monitoring of a steel building specimen on the full-scale shaking table test is conducted to investigate modal properties of a passively controlled steel building subjected to large earthquakes. Changes in the dynamic properties are evaluated from the continuous ambient vibration test, which are related to damage detectability from ambient vibration or earthquake observation on real buildings. The results in the paper are summarized as follows: (1) The shifts in the first natural frequency due to the construction works and seismic experiences can be detected clearly. (2) Within tiny deformation of ambient vibration different characteristics in natural frequency or damping factors is observed in use of different types of seismic control devices.