Tokyo Tatemono Co., Ltd. : Notice of First-Stage Completion of THE OTEMACHI TOWER

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FOR IMMEDIATE RELEASE

August 29, 2013

Tokyo Tatemono Co., Ltd.
Taisei Corporation

Tokyo Tatemono Co., Ltd. (headquartered in Chuo-ku,Tokyo; Hajime Sakuma, President) and Taisei Corporation (headquartered in Shinjuku-ku, Tokyo; Takashi Yamauchi, President) announced that the first stage of Otemachi Tower, being developed by Tokyo Prime Stage Ltd. in Otemachi 1-chome, Chiyoda-ku, will be completed on August 30. The development of Otemachi Tower will result in the widening of the concourse of Otemachi station on the Tozai line, as well as creating barrier-free access, enhancing the underground pedestrian network in the Otemachi district. Otemachi Tower has been assigned "Platinum" certification by the Development Bank of Japan, the highest rank of "DBJ Green Building Certification (Plan Certification)".
The grand opening of the first phase of the commercial zone Ootemori is scheduled for Wednesday, October 2 this year . (The dedicated website will be launched on September 2nd at URL:http://www.ootemori.jp.)

Otemachi Forest: a genuine forest created in the business hub of Otemachi

The most distinctive feature of Otemachi Tower is Otemachi Forest, which extends over approximately 3,600m2, corresponding to around one third of the total site. This is a new initiative in urban development, and embodies the project's development concept of "regenerating the city and the natural environment at the same time."

Here, we present once again the concept, process, anticipated benefits, and other information in respect of Otemachi Forest.

1. Concept

It is seven years since a concrete investigation began in response to the idea that it would be interesting if, rather than simply planting trees, a genuine forest were created. This
marked the start of the challenge to "regenerate the city and the natural environment at
the same time," a proposition that went against the prevailing common sense.
So what is a "genuine forest"? A genuine forest has intricate undulations in the ground, resulting in water flowing in marshes, and consists of plants with different growth conditions such as evergreens, deciduous trees, and ground cover plants.
Further, because of the density of the trees and the difference in their height, solar radiation and growth conditions vary, with trees that lose the battle for survival decaying, turning into natural fertilizer, and eventually breathing life into new shoots. The fundamental principle of Otemachi Forest is the reproduction of this ecosystem to the extent possible. (The photographs show the "pre-forest" growth conditions.)

2. Process

When selecting the trees and ground cover plants, the topographical classification (such as characteristics of the soil), and the climate classification (such as potential natural vegetation in accordance with the climate) of the Otemachi area were taken into account, and over 200 tall trees were arranged. Also, the "pre-forest" method was used in order to reproduce a "genuine forest" in Japan's leading business district. This entailed the construction of a site in approximately 1,300m2 (around one third of the total area of Otemachi Forest) of forest in the mountains of Kimitsu, Chiba Prefecture, that mirrored the planned site for the Otemachi Tower, reproducing the undulations of the earth and the inclines of concrete slabs, the density and varieties of trees, and other features. The growth situation of the vegetation and appropriate management methods were verified over a period of around three years, before transplanting the forest to the site of the Otemachi Tower.

Pre-forest conceptual diagram

Verification

?Design

?Maintainability

?Safety

Kimitsu

Creation of undulation reproducing the subsurface framework

Temporary planting of trees and ground cover plants complete

3 years

Transplant

Otemachi

3. Benefits and Role

A block of greenery of around 3,600m2 will reduce the heat island effect, as well as help to control urban flood damage through the water retention function of the soil, even if there is localized torrential rain. An additional expected benefit is that of increasing the number of bases from which wildlife can move, as well as wildlife numbers in the area as a whole.

General plan of outdoor facility that integrates

pedestrian space and green space

Otemachi Forest is separate from pedestrian space, thus

preserving a block of green space

Image of the effect on creating "cool space"

Image of the effect on controlling urban flood damage

Project Outline

Location: 1-5-5 Otemachi, Chiyoda-ku, Tokyo
District: Commercial district, fire protection district
Otemachi-Marunouchi-Yurakucho district zone planning, Tokyo
Metropolitan Government planned urban renaissance special zone
Ground area: 11,037.84m2
Total floor area: Approx. 198,000m 2
Floor-area ratio: Approx. 1,600%
No. of floors: 6 floors underground, 38 floors aboveground, 3 penthouse floors
Height: Approx. 200m
Construction: Underground: Ferr-o-concrete construction / aboveground: steel frame construction(ultrahigh-strengthCFTcolumns)
Ceiling height: 2,900mm (+OA flooring 100mm) (officestandardfloor)
Floor load: Regular part 5,000 N/m2, heavy duty zone 8,000 N/m2 (office standard floor)
Occupancy: Offices, hotels, stores, parking lot, etc.
Design: Taisei Corporation First-class architectural firm
Execution: Taisei Corporation, Tokyo Branch
Construction work
supervision: Nihon Sekkei, Inc.
Construction period: Start November 2009 - first stage completion August 2013 (overall completion April 2014)

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