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Structural System

The building is composed of thirteen independent steel-ribbed shafts (tubular columns, mainly steel-tube truss construction) and seven steel-ribbed 'honeycomb' slabs of sandwiched steel-plate construction. The basement also features seismic energy-absorbing mechanisms.

Air-conditioning System

Upper vents on the double glass ("double skin") south facade reduce air-conditioning costs. Opening the vents in summer creates a cooling updraft; closing the vents in winter creates an insulating layer of air to seal heat in.

Natural Light, Wiring and Vertical Connections Through the Tubes

The tubular column structures serve as light wells, with rooftop devices to reflect sunlight down the tubes into the building, and also as vertical connector "pipelines" for network cables, wiring, elevators and stairways.

Site Area:
3948.72 sq.m.

Building Area:
2933.12 sq.m.

Total Floor Area:
21682.15 sq.m.


7 stories, 2 basement levels

Steel frame, Reinforced concrete

Start of Construction:
17th December, 1997

Completion of Construction:
10th August, 2000

Total cost:
Approx. 13 billion yen

Toyo Ito & Associates, Architects

Structural Engineers:
Sasaki Structural Consultants

Mechanical Engineers:
ES Associates, Sogo Consultants, Otaki E&M Consultants

Sendai City Urban Environment Maintenance Bureau

Commissioned Administrator:
Toyo Ito & Associates, Architects

General Construction:
Joint Venture (JV) of Kumagai + Takenaka + Ando + Hashimoto

Electric Equipment (heavy current):
JV of Yurtec + Taihei Denki + Higashiyama Electric Works

Electric Equipment (light current):
JV of Nippon Densetsu Kogyo + Miyagi Densetsu

Air Conditioning Equipment:
JV of Taikisha + Daiichi-kougyosho + Atmax

Plumbing Sanitary Equipment:
JV of Nishihara Engineering + Hokuei-kougyosho

Elevating Machine Equipment:
Mitsubishi Electric