“A city where people can take refuge, rather than evacuate from”
Before Roppongi Hills was developed, the neighborhood had a high density of low-rise, wooden buildings. Fire trucks could not enter the very narrow streets. One important redevelopment goal was making the neighborhood a safe and secure place to live in.
A feature of every building is an earthquake-resistant design incorporated into each building’s plan to prevent damage in the event of an earthquake of a scale of the Great Hanshin-Awaji Earthquake.
Our slogan for earthquake and disaster preparedness is to build “a city where people can take refuge, rather than evacuate from”.
A variety of technologies are employed at Roppongi Hills to create a city that can strongly withstand earthquakes and avoid damage during a disaster. Damping and seismic base isolation (vibration damping at the base of a building) are some of the technologies used to create greater resistance to earthquakes, particularly in high-rise buildings.
In systems using oil dampers, the resistance generated when the oil in the cylinders moves absorbs building vibration. Sensors installed in the devices detect small vibrations, and the oil is rapidly forced to move in a controlled manner. This shock-absorber effect not only serves to dampen vibration during a large earthquake, but also serves to reduce vibration and swaying caused by medium and small earthquakes and by wind. Mori Tower has 356 oil dampers installed in columns and beams in the building. This creates an excellent earthquake-resistant system.
Viscous wall dampers
Viscous wall dampers are installed in Roppongi Hills Residence B and C towers. In this system, substances with high viscosity are injected into box-shaped steel slabs. Resistance is generated when an independent steel vane in the slab (or plate) moves in response to vibration. This has the effect of significantly reducing vibration due to earthquakes or wind. Each floor in the buildings has 8 viscous wall dampers.
Steel tubes filled with high-strength concrete are placed in the pillars that form the framework of the buildings. This provides superior resistance compared to conventional construction methods. These pillars with excellent bending strength are part of the construction of Mori Tower, Grand Hyatt Tokyo, Roppongi Hills Residences B and C towers, and the Hollywood Beauty Plaza.
Green mass damper
A pendulum effect is utilized in the building structure itself and for the rooftop greenery section insulated with rubber layers to absorb seismic energy. (Normally it is the same when damping construction is used.) When the insulated rooftop section is subjected to strong vibration, the pendulum effect comes into play, dampers between each layer absorb seismic energy, and stress on the main building structure is reduced.
These are used at the Roppongi Hills Keyakizaka Complex.
Disaster control measures
The area is fully prepared for emergencies, including times when drinking water is cut off due to an earthquake, etc. Wells have been constructed to secure drinking water, water for flushing toilets, and water for fighting fires. Emergency electric power generation systems are in place, and emergency food supplies have been stored.
The storage warehouses hold things such as emergency supplies of food, drinking water, portable toilets, blankets, medicines, first-aid supplies, materials to be used in recovery, and paper diapers and powdered milk for babies.
Wells for use during disasters
Two sites with well infrastructure (urban infrastructure) indispensable to maintaining daily life during a time of an earthquake or other disaster have been constructed at 2 locations in Roppongi Hills. As part of the preparation for the water supply being lost for long periods of time, in addition to water for such uses as toilet flushing and cooling water for electricity generators, under arrangements made with neighborhood associations, the wells will be used to provide water to surrounding districts, mainly for miscellaneous use and for firefighting.
Water has been stored for use as drinking water, but should the supply become insufficient, these wells will be used to supply drinking water. As-is, the water from the wells is not suitable as drinking water. However, filtration sterilization devices can be used to purify the water to make it potable.