Initiatives to Enhance Disaster Preparedness in Buildings
Top Level Seismic Performance to Withstand Megaquake
(Seismic Intensity 7)
Buildings owned by Mitsubishi Estate in the Otemachi, Marunouchi, Yurakucho area have seismic performance that is at least equivalent to that set out in the Building Standards Act (new earthquake resistance standards), even for buildings that were built prior to the enactment of new earthquake resistance standards. Moreover, based on original standards for earthquake resistance formulated with Mitsubishi Jisho Sekkei that exceed those required by laws and regulations, Mitsubishi Estate has ensured that the seismic performance of ultra-high-rise buildings constructed since 2002 is 1.5 times higher than that of conventional skyscrapers and that it is possible to remain in the building even in a seismic intensity 7 megaquake.
Area BCP Initiatives Based on Area Disaster
Completed on April 1, 2016, the Otemachi Financial City Grand Cube is an ultra-high-rise building designed with advanced disaster preparedness functions that considered lessons learned following the Great East Japan Earthquake, which took place during the planning stage of its development. All conceivable flood damage measures were taken to minimize risk in the event of a flood, such as installing flood barrier panels, water-tight doors and other water barrier measures, and locating a stockpile warehouse and important offices (transforming equipment and disaster prevention center) on above-ground floors. Mitsubishi Estate has employed a full range of inventive methods in its quest to build an advanced disaster-resistant city. An urban water purification system was installed, which is a first for a private company, and also installed was a system that allows electricity, water and ventilation to function independently in the event infrastructure services are interrupted. Having learned from heightened demand for bathing in regions affected by the Great East Japan Earthquake, Mitsubishi Estate excavated out hot springs from a depth of 1,500 meters and opened a bathing facility. This facility will be made available for use by disaster relief personnel in emergencies and to improve hygiene.
The company has also developed collaborative systems for emergencies, such as an affiliation with St. Luke's MediLocus, an international medical facility.
As a result of these efforts, Grand Cube was designated a disaster response base by the Council for Area Development and Management of Otemachi, Marunouchi, and Yurakucho, and it will take an important role in improving disaster resilience for the area overall.
Details on functions for BCP and the safety, security and BCP of Mitsubishi Estate's office buildings are shown in the pages below.
"Disaster management center building" contributing to the BCP of the entire district
Exterior of Otemachi Financial City Grand Cube
Introducing Systems to Enable Timely Response to Earthquakes
Mitsubishi Estate has introduced varied systems to detect seismic disturbances, evaluate the level of damage automatically, and thereby enable a timely response in the event of an earthquake.
Installation of Yuremasu Seismographs
With the aim of conducting elevator safety shutdowns and preventing lock-in accidents whenever an earthquake occurs directly beneath Tokyo, Mitsubishi Estate has installed Yuremasu seismographs developed by Mieruka Bousai Co., Ltd. in various facilities in the Tokyo metropolitan area, operated by the Mitsubishi Estate Group. The system rapidly conveys seismic P-wave data measured at each facility to high-rise buildings in the Marunouchi area, making it possible to implement safety measures that include emergency shutdowns of elevators prior to the arrival of strong swaying.
Installation of Damage Level Evaluation System
Mitsubishi Estate has introduced a damage level evaluation system that ascertains a building's damage condition during an earthquake based on data from seismographs installed at several locations inside buildings, and then rapidly determines whether continued use is feasible. We have been installing this system in skyscrapers in the Otemachi, Marunouchi, Yurakucho, Yokohama, and Aoyama areas beginning with the Marunouchi Building, the Shin-Marunouchi Building, and the Marunouchi Park Building.
Introduction of Center Functionality
Mitsubishi Estate and Mitsubishi Jisho Property Management have introduced center functionality that allows for remote and integrated monitoring of buildings owned by the Mitsubishi Estate Group.
Reinforcing Communication Equipment
The Group also works to reinforce communication equipment (digital MCA and IP radio systems) in each company facility to address congestion of the general phone lines in the event of an emergency.
Countering Long-Period Ground Motion at Sunshine 60
The Great East Japan Earthquake, which struck in 2011, caused significant, lengthy continuous swaying of skyscrapers in the Greater Tokyo region as a result of long-period ground motion. There are concerns that damage could result from long-period ground motion that will occur during major earthquakes expected in the future.
In order to counter long-period ground motion at Sunshine 60 in Ikebukuro, Tokyo, Mitsubishi Jisho Sekkei Inc. launched a research society together with Sunshine City Corporation, the owner of Sunshine 60, and construction company Kajima Corporation, in order to research and investigate long-period ground motion, well ahead of the point when long-period ground motion was recognized as a major concern. Additionally, we developed Japan's first "damper assembly construction method"—an effective combination of three types of dampers based on the results of this research and investigation, and installed seismic strengthening measures at Sunshine 60. Construction was completed in 2016. Using this construction method, we achieved long-period ground motion countering that demonstrates greater earthquake resistance than the newest skyscrapers, and without affecting the building's tenants.