Morphosis explained the project as follows:
|Phare Tower — Aerial view of the site (tower in construction), Morphosis, Paris-La Défense, France, © Morphosis|
|Plan © Morphosis|
|Plan © Morphosis|
The Phare Tower (phare being French for beacon or lighthouse) marks first stage of a major redevelopment of the district. La Défense is currently a zone of discrete, isolated buildings amid blank plazas — essentially a nonsite.
|Site Plan © Morphosis|
|Site Plan © Morphosis|
> Technologies integrated to the Phare Tower capture
the wind for the production of
energy and selectively minimize
solar gain while maximazing glare-free
At the levels of urbanism and circulation, the scheme complements existing plans to transform the CNIT into a center for commerce and recreation. Circulation is directed from the existing transit hub below grade, through the renovated CNIT facilities, and into the tower's public spaces via a pavilion. The pavilion connects to the Place Carpeaux, and transitions from horizontal to vertical, becoming an integral element in the tower's form. Glazed exterior escalators soar 35 meters from the pavilion to the tower's ninth-floor lobby, transporting Grand Hall, the fully glazed envelope reveals views of the traffic passing underneath, as well as of Parisian monuments in the distance.
Rather than an isolated and autonomous tower, the building is a hybrid structure. The 300-meter tower straddles the site to meet the ground as a tripod. It comprises one splayed structural leg, two occupiable legs (the Trapezium, to the west, and the East Building), as well as a pavilion that engages the surrounding context the transforms the public space of the plaza.
The two occupiable legs frame a 24-meter-wide by-28-meter-tall void in the tower's base, creating a monumental urban gateway, which maintains view corridors toward the CNIT and toward Courbevoie and allows pedestrian traffic to flow directly underneath the building.
As it rises from its tripod base, the tower's asymmetric profile swells slightly to accommodate the soaring Grand Hall, then becomes more slender in response to wind load, and finally tapers off to a thicket of wind turbines, antennas and hair-like structures on the roof. The tower appears to shift continually, distinct from different vantage points — not a single image but a dynamic structure that responds to its site, environment, and performance requirements. As its base, the building's skin opens, exposing a 250-foot-high Grand Hall. The Grand Hall becomes the center for all vertical transportation. From the Hall's security checkpoint, people transition to double-deck banks express elevators serving the office tower. On the 66th floor, a sky restaurant and a panoramic terrace, offering spectacular 270-degree views, are open to the public. Overall, the project comprises 146,988 square meters or 1,582,166 square feet of net surface area and 164,185 square meters 1,767,273 square feet of gross surface area.
Technologies integrated into the Phare Tower harness the wind for the production of energy and selectively minimize solar gain while maximizing glare-free daylight. The tower is crowned with a cluster of antennas and a wind farm of turbines that harvest energy — metaphorical garden in the sky. Both the form and the orientation of the building respond to the path of the sun. The planar, clear-glazed north façade maximizes interior exposure to year-round natural daylight. A curvilinear second skin of diagonal stainless steel mesh panels wraps the tower's continuous south, east, and west glazed façades to minimize heat gain and glare and maximize energy efficiency."
As this description shows, the tripod Phare tower consists of a structural leg, two legs for the commercial space, and a plaza pavilion, occupying an irregular shaped site bordered by the highway, a rail link and a pedestrian walkway.
> This complex structure and skin (…) responds
to a range of complex, and often
competing, physical and environmental
Morphosis's design depends on the site's size, disposition, and low-bearing capacity. The shape of the building — curved south-facing facade, and flat north-facing facade — responds to its environment, precisely, the wind load, and the sun. This tower's core elements, mostly, are composed of an optimized skin system, a roof wind farm, and an aerodynamic form.
The optimized skin system first. The skin is optimized to respond to the site constraints. A dual orientation of the building plays an important role in the form of the building. It responds to the path of the sun. The south façade is made out of a curved double skin which aims to minimizing heat gain and glare.
> Curvilinear south-facing facade
to minimize heat gain and glare (T.M.).
> Flat, clear glazed north-facing
facade to maximize interior exposures
to natural daylight (T.M.).
Brise-soleil will wrap the building's continuous South, East, and West glazed facades. The choice for this double-membrane façade system, as Thom Mayne explains, permits to improve both energy efficiency and comfort of the occupants.
> Skin has been optimized to respond to
the site constrains: wind load and sun.
The building becomes opaque,
translucent, or transparent
from different angles and vantage points (T.M.)
The second point of the sustainable part is the roof wind farm system.
A wind farm dissolved by a diagrid structure, that is, a group of helical vertical axis wind turbines will be used to produce energy. Wind farm provides clean, alternative energy. Precisely, this group of wind turbines is a passive venting system which does not use electricity and is noiseless. As Thom Mayne says, "this powerful statement of environmental responsibility literally crowns the building". Power for the general services of the upper floors of the tower will be provided by this wind farm system.
> The steel diagrid structural system
results in a lighter building, which facilitates
the placement of such a tall tower on a small site with
low bearing capacity… (T. M.)
> A diagrid — a grid with diagonal geometry — used in
a vertical format can thus eliminate the need for large
corner columns by providing lateral support, and produce
shapes that are crystalline or smooth, for example
in high-rise structures (Farshid Moussavi, The function of Form)
The last important part concerns the aerodynamic form. The architecture firm uses powerful software — both for scripting, engineering. This Phare tower reflects Morphosis' research on advanced and innovation in architecture, engineering, sustainability and manufacturing. As mentioned in the description part, the structure is an efficient hybrid concrete and steel system.
The concrete core will sustain the vertical load only.
As for the steel beams and diagrid, they will be the shape, the ideal shape according to Thom Mayne, to withstand windload. This results in material saving and a reduction in building weight. This strategy appears to be a good response to the small site with low bearing capacity, while occupied by high-rise buildings.
Project: Phare Tower
Program: Commercial office tower with office space, employee restaurants, public cafés and amenities, panoramic restaurant
Client: SCI CNIT Development
Location: Paris-La Défense, France
Site: 164,180 gross sqm (1,767,273 gross sqf)
Design date: 2006-2010
Construction phase: 2011-2015
Completion Year: Expected for January 2015
All models, plans, renderings © Morphosis