Conventional construction methods are in many cases no longer able to keep pace with today's increasingly intricate and difficult building designs. Innovative techniques such as the "sliding" and "lift-up" methods pioneered by Kajima are enabling complex large-scale structural members to be assembled as complete units in accessible staging areas and then maneuvered into place, thereby realizing major gains in safety, efficiency and design flexibility. A notable example is the 9-story-high spherical observation deck and restaurant which was recently erected at the FCG Building, now under construction at the 448-hectare Bayside development known as Tokyo Waterfront.
Designed by Kenzo Tange Urbanists-Architects and Kajima affiliateKobori Research Complex, Inc., the FCG Building is a 25-story steelframed and composite structure distinguished by a 32m-diameterobservation sphere set between the tops of its two towers andconnected to them by means of an elevated skyway. The building'scomplex structural design posed numerous construction challenges, notthe least of which was erecting the 1,200-ton titanium observationsphere at a height of 123 meters above ground.
Kajima successfully met this particular challenge by employing its unique "lift-up" method to construct the sphere and attached corridor framework as an integrated unit at a temporary staging area on the building's seventh floor and lift it into place in phases by means of hydraulic jacks. The process was further complicated by the observation structure's asymmetric load distribution, which necessitated locating the jacks at three separate support points - to which differing levels of force were applied - and closely coordinating the eccentric jacking operations. Prior to this in Japan, the lift-up method had only been used for raising symmetrical objects with evenly distributed force.
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In addition to the observation sphere and skyway, connection corridors at the building's eighteenth and twelfth stories were also "lifted up" into place using the same equipment. Carried out in two one-day phases, lift-up operations took place on April 17 and May 9. When completed in June 1996, the FCG Building will serve as the new headquarters of Japanese media corporation Fuji Sankei Group, housing a television Studio, broadcast facilities, a theater and various administrative offices. Utilizing Kajima's innovative Lift-Up Method, FCG Building's 32m-diameter, 1,200-ton titanium observation/restaurant sphere and adjoining corridor framework were constructed as an integrated unit at a temporary staging area on the building's seventh floor and raised into place 123 meters above ground by means of strategically placed hydraulic jacks. Photo series at right shows successive stages (bottom to top) of lift-up operations. |
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