Newsletter 2013.4 Index
Theme : "Fluids Engineering for the World窶冱 Top Technologies"
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Tokyo Sky Tree (Fig.1) is a new core facility of digital broadcasting for Tokyo metropolitan area of Japan, and it is required high criteria because of its heavy public responsibility to send valuable information to the victims in a big disaster.
The maximum disturbance for the structural design is the strong wind(Fig.2) that wind speed is 83m/s at the top of this tower, and the big earthquake that the response spectrum is over 100cm/s (h=5%) at the natural period of this tower. While, the structural safety limit according to L2 disturbance, the maximum level that the building regulations in Japan require to the domestic buildings, is almost no damage.
Unique systems for vibration control, the core column system (Fig.3) and the rigid substructure system, were invented for this tower to satisfy the severe requirements. The core column system uses the core shaft of the emergency staircase built with a reinforced concrete tube wall as a weight applying the theory of TMD, tuned mass damper. This vibration control system is effective in the wide range and a lot of kind of earthquake. It can reduce maximum 50% the acceleration response during the earthquake and maximum 30% during strong wind.The rigid substructure system constitutes of a rigid wall pile and soft ground, and makes use of a relative displacement between the rigid substructures and soft ground to gain damping ability, the radiation damping.
Broadcast Tower ; Array observation ; Aerological wind observation ; Wind tunnel experiment ; Artificial wind wave ; Vibration control systemr
Fig. 1・啜okyo Sky Tree
Fig. 2・哺easurement of wind
Fig.3・售ection of the core column