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		Background
		The head office is the first of what Nikken call sits "third generation' high-rise buildings, wherein design considerations include a substantial concern for the environment. In these Nikken buildings such concerns significantly shape the structural system and the overall form. Housing the headquarters of well-known Japanese electronics giant, the Nippon Electric Company (NEC), the building is a gradually tapering 43-story-high tower. As the building soars upward it becomes narrower by the application of two setbacks. The resulting shape is less imposing than a traditional high-rise and ensures the provision of longer hours of sunshine to the surrounding area. The NEC super tower has several unusual features that make the building, despite its monumental proportions, a better fit in the context. First, the designers took advantage of the relatively generous site and surrounded the building with a forest of planted trees and greenery to counter the concrete desert of the site. This green area is, in effect, a continuation of the nearby Shiba Park and the Keio University campus, which connect to the waterfront of Tokyo Bay in a natural chain.  A high-rise building inevitably has some impact on its environs. This is especially true when the building is constructed in a densely built-up, heavily populated district of mostly low-rise structure. It is clear that a high-rise introduced into such a setting cannot ignore the existing architectural environment, so the architect strives to make his building compatible with the neighborhood. The more emphasis the places on achieving this compatibility, the more strongly his high-rise will be influenced by its surroundings.   The NEC Supertower is a case in point. The lower part of this building was designed to relate to the 50m, or so, high skyline formed by a number of adjacent buildings, above which stands the mid-level part of the tower. This in turn supports the narrower top portion. It is these three setbacks that give the building its distinctive overall form.  The opening between the lower and mid-level parts of the building, 42m wide by 15m high serves as a large "wind vent" allowing strong high-level winds deflected down the face of the tower to "escape" downwind, instead of being diverted further down the facade, where they could have adverse effects on the surrounding low buildings and pedestrians in the street. The opening also serves as a large "window"  through which daylight enters the atrium and entrance hall located centrally in the low-rise part of the tower. Basic Data: Section Location: Minato Ward, Tokyo, Japan Architect: Nikken Sekkei Planners, Architects and Engineers Structure: Steel frame (central part aboveground) Steel frame and reinforced concrete (Central basement) Reinforced concrete (peripheral basement) No of storey: 4 basements, 43 stories, 1 penthouse Completion: January, 1990 Site area:  21,280m2 Building area: 6,370m2 (Building coverage ratio is restrained to 30% to provide the rest of the site with a green zone.) Total floor area: 145,100m2 Overview: necex1.jpg 107.85 Kb  necex2.jpg 110.63 Kb  necplan.jpg 28.57 Kb  Interior: necin1.jpg 106.75 Kb  necin2.jpg 67.27 Kb  necin3.jpg 73.85 Kb  Reference: FACT - Nikken Sekkei  Brochure from Nikken Sekkei  Japan Architects  Building Future Japan 1900-2000 | Energy Saving | Case Study Index | | Created: 20 Aug 2001 | Update: 22 Aug 2001 | By: cmhui@hku.hk |