Paris’ CBD La Défense Strategic Masterplan

In 2012, public institution DEFACTO, selected AWP, Office for Territorial Reconfiguration, (Marc Armengaud, Matthias Armengaud, Alessandra Cianchetta) in partnership with HHF, to provide design and implementation guidance for La Defense, Central Business District. The objective was to conceive a new strategic master plan for the entire (161 hectares) site that addressed issues of public space—green space, urban infrastructure, circulation, transportation and site evolution— specifically as they relate to the 30 hectare slab.

THE CHALLENGE OF THE SLAB

The project at La Defense is most strongly defined by its programmatic and spatial complexity. This is especially evident in the multileveled nature of circulation, infrastructure, and occupiable space. What appears on the surface as just a slab, is in actuality, just a small part of a larger system. The slab, functioning as a hybrid ground, serves at once as the pedestrian walkway, a roof to 6 stories of underground infrastructure, and a wall to surrounding streets all the while floating above a transportation hub. In this way, it epitomizes the relationship between landscape, architecture, and infrastructure. In response, a set of guidelines proposed by AWP and HHF reimagines the slab as a key connector in the site instead of a barrier, maximizes efficient use of the space in, on, and around the slab, and develops a holistic vision for a new cultural and programmatic culture on the site.

The new plan strategically links Paris to the CDB, strengthens connections to the surrounding neighborhood, and integrates the underground transportation. The guidelines create a framework under which the CBD can build new towers, remodel extant commercial properties, design spaces for exercise and cultural events, install a network of green and open spaces, expand infrastructure and transportation, and evolve planning structures over the next 20 years.

This plan also envisions the long-term evolution of the site and identifies possibilities to extended infrastructure to adjacent neighborhoods. Guiding principles for design include: (1) redefining the ground (through interventions on the slab), (2) reestablishing the grand axis, (3) inhabiting in-between spaces, (4) allowing for a natural invasion, and (5) incorporating shared spaces.

EXPLORING THE UNDERGROUND

Beneath La Defense lay several train and metro lines (metro line 1, RER A), a highway (A14 route), and as well as a large number of parking, but there is little character to these spaces. The plaza is envisioned as the central hub of the project, which connects people to all aspects of their life at La Defense: interface to parking, link to work, access to the stadium, cinema or shopping centre. Multileveled systems pose a number of serious challenges and opportunities for design. On the one hand semisubmerged roadways contribute to a safe and pedestrian-oriented central plaza, yet permeability between levels is often weak. In order to formulate the relationship between vertical and horizontal territories, a new design strategy is proposed. The surface is cut through, subterranean parts are day-lighted, visual connection is established, and circulation systems are added.

The vision is that in the future, the underground can function as more than a transition route to other destinations, but rather become a destination in itself, a meeting place, and a place for programmed activities. Thus, this axis is the medium to penetrate the greater richness of the site and, in this way La Defense can serve as a model for exploiting the full potential of the underground.

In response to this challenging condition of the site, it was necessary to develop the theme of “depth” in a rather literal sense: creating places for living within the areas now used for parking.

Through site analysis and spatial reconfiguring, were able to re-find 100,000 square meters of underused spaces in between buildings and between level changes that have great potential to link important locations. As part of the intervention’s first goals, the potential value of the underground network at La Defense is developed to a maximum extent particularly as it serves as the interface between subterranean parking, metro lines, and the elevated walkway that links office buildings.

PROJECT PHASES

The first phase of the project includes analysis and a site diagnostic evaluation.

The diagnostic phase is comprised of analysis that resulted in a series of data maps. In the case of plan guide public areas of La Defense, this phase was essential for the understanding of the site. The first task of the study was to create a system of representation, to compile an atlas of public spaces, and gather unpublished data owned by different actors on the site. A series of walking workshops were conceived of as a new way to generate knowledge from the site`s operational actors:

Defacto, employees and residents, and other visitors to achieve a sensitive experiential mapping of the visit. These steps helped us the read the site and break it down into programmatic typologies and a set of targeted interventions. After the diagnostic phase, a general program was established based on our five principles.

The five principles set out in the order of importance, and are grouped under the title as Towards a climate.at This phase was essential to the understanding of the site and also for producing 10 themed books which outline the different layers of public space of La Defense.

These strategies also helped to structure proposals and formulate a strategy for implementation.

The second phase focuses on infrastructure, there will be profound changes to the character of the neighborhood, driven by a stronger engagement with public space.

Wayfinding will be improved, so that one can take pleasure in walking and driving around La Defense, as one would in the centre of Paris. The ring road will mutate into an urban boulevard; pavements and walkways will be renovated and connections to nearby Puteaux, Courbevoie and Nanterre will be improved. As a result, to La Defense serve as a critical link in a larger network of streetscape interventions from one bend of the Seine to the next and between Paris and its surrounding hinterlands.

Defacto has already begun important work to simplify and improve access for road users and pedestrians, upgrade car parking, install a new signaling system on the plaza, a new lighting plan and unify wayfinding, street fittings and advertising signs.

FIVE STRATEGIES FOR DESIGN

1. re-invent mobility/redefine the ground.

Entryways, thresholds, and circulation routes between La Defense and the peripheral neighborhoods were all addressed as crucial components to future success of the project. The proposed network of paths and open spaces function as the connective tissue between currently disjointed buildings, levels, and areas.

Improving navigation in/under/around the slab is central to the master plan, as well as to the public’s interaction with the greater La Defense-area.

2. re-establish the grand axis.

The Parisian grand axis is maintained, but it is mutable in response to existing conditions. The networks of greenspaces around this new axis are added to, updated, and re-imagined; they provide the area with new character, programmatic potential and experiential continuity. The new network of promenades, planted routes, a system of way finding devices, and improved entryways stretch outward from a central spine and offer direct access to the surrounding neighborhood and other peripheral sites. The central axis is envisioned as a rich “oasis” of nature and urban identity, which fuses architecture, landscape, art, and community.

3. inhabit in-between spaces.

An integrated system of infrastructure will increase access to the site and ultimately improve navigation within the site. Attention to a variety of landscape conditions creates interim settings, each interesting in their own right, which give form, focus, and character to different parts of the site. Simultaneously, a system of integrated design strategies and aesthetic vocabulary retains a sense of coherence and integrated whole. Hard and softscape paths, street furniture and wayfinding devices were also proposed particularly at in-between spaces to achieve these goals. Through a series of analyses aimed at exploring under-utilized spaces on the site, we discovered 100,000 square meters that had the potential to be used for program, circulation, or landscape.

4. allow for a natural invasion.

The design proposal maintains that landscape should both adapt to the context of the plaza and take on a more radical form, so that it helps define a new character. The landscape network aims to engage people throughout the site. We at once respect the existing infrastructure and site conditions while employing landscape strategies as a way to occupy and engage the site. A hybrid of landscape interventions introduces new landscape typologies and meets a wide variety of user needs. The proposal includes hardscape areas that capture vistas and facilitate easy movement through the site, a plaza for largescale gatherings, lawns and fields for recreation and sport, and quiet gardens for sanctuary.

5. incorporate shared spaces.

The plan aims to develop the current assets of the site. Building upon the current art collection, public buildings and world renowned corporate presence, the proposal thus outlines an approach for La Defense to become a greater center for tourism, culture, economy, and the arts. We also rethink the role of public interior spaces; for example, defining ground floor atria as giving access not to towers, but as extending interior rooms to open space, thus blurring the boundary between public space and private interior.

As we conceived of the new character of the site, we established a critical relationship between the visible and invisible components: above ground and underground, building and infrastructure.

Most importantly, we aim to develop a new “climate” on the site. While invisible to the eyes, experiential quality to the site was central; we wanted to create a space that felt safe, comfortable, lively, and ever accommodating to the needs of its users. Thus the climate will be the defining memory of La Defense, an innovative space full of contrasts that is infinitely more hospitable than the immense, stark landscape of the current site.

We were also looking at depth on the site so as to anchor the buildings and to help overcome the current sense of it being an illogical pile of disjointed buildings. If the navigation is strong enough, the museum, the hybrid landscapes and the event spaces can extend underground and this new climate can permeate between layers and link many places.

A developing new nighttime identity for the site is also of primary concern to the success of the future of the site. La Defense is strongly contrasted busy and calm periods (morning/ lunch/leaving the office, day/night, working week/ weekend, seasons…).

Presently, night transforms the space under the plaza (in a negative sense, couched in the shadows of the parking garages) and ends in the towers (as corporate sculpture). By changing the nocturnal identity of public spaces at La Defense, we can alter the experience of the site from a series of spatial constraints to an urbanism of temporal opportunities. The question of light, and therefore of a nocturnal plan, is particularly important to developing this alternative dimension of the site. As part of the complete proposal, the firm developed a way to think of the night as a profound untapped space, which can be enhanced by a lighting system for a 24-hour, global population. Thus, the plan calls for a more human, sensitive and artistic approach to the night, an overarching system of artificial lighting, choreographing movement through the site, and temporal flexibility. As new uses integrate into La Defense, there will be logistical concerns adjustments to accommodate more nighttime visitors: new infrastructure like a stadium, parking garages, attention to lighting and wayfinding devices, and art installations.

Recomposer le prisme des espaces publics pour faire naître un climat

L’Agence de Reconfiguration Territoriale AWP (Marc Armengaud, Matthias Armengaud, Alessandra Cianchetta) livre aujourd’hui sa vision stratégique pour le quartier d’affaire de La Défense. L’objectif a été de concevoir un nouveau plan directeur, appelé à être le document de référence pour l’ensemble du site (160 ha) et répondre à des questions face à l’espace public à La Défense – espaces verts, infrastructures urbaines, système de rue, transport, évolution du site.

Vers un climat

De la réflexion sur une évolution du rapport au « climat » de la Défense (se protéger du vent !), on peut évoluer vers une vision générale des qualités d’espace public. Créer des « oasis premium » sur/sous/autour de la dalle, pour définir la Défense comme écrin de nouvelles relations entre nature et urbanité. Le « futur » ne doit pas s’affirmer que dans les architectures : paysagistes, designers, artistes, sont porteurs de nouveaux langages d’hybridation dont la Défense pourrait être la scène privilégiée : c’est un étrange paradoxe que ce soit dans Paris intramuros que soient en train de se développer les hybridations ville/nature les plus marquantes de notre région, dans une ville ancienne, compacte et presque entièrement muséifiée. La Défense a un potentiel beaucoup plus important d’évolution vers une « post-nature urbaine » exemplaire. Le souvenir qu’on emporterait de la Défense, serait l’expérience de climat, nécessairement contrasté et innovant, et plus accueillant que l’immense minéralité qui en est aujourd’hui l’image et la réalité.
Travailler le motif de la profondeur au sens littéral : habiter les parkings et les épaisseurs et les liaisons avec le pourtour. Mais aussi au sens d’un positionnement moins immédiatement marketing : la Défense a besoin de s’imposer comme figure consistante, et pas seulement comme empilement de logiques disjointes, et concurrentes. Déplier la Défense dans ses épaisseurs. Faire commencer l’espace public dans les profondeurs, diffuser cet esprit dans toutes les voies d’accès et essayer de trouver des échos dans les halls et les façades des tours. En apportant une attention toute particulière aux marqueurs de liaison et de mise en relation : seuils, repères, correspondances visuelles… Le musée, les natures hybrides et les scènes événementielles peuvent se diffuser en sous-sol.
La nuit comme révélateur critique de la valeur des espaces public et fil conducteur d’un rapport renouvelé au grand quartier de la Défense : nature artificielle, expériences urbaines, scènes, flexibilité temporelle… Il y a également de nouvelles pratiques (avec le stade) à encadrer, stimuler et capitaliser. Penser et agir à partir du temps, des flux, et des interactions. Il y a par exemple assez de parkings pour absorber beaucoup plus de visiteurs nocturnes que la dalle n’en accueille. Une partie cruciale de cette stratégie nocturne doit rester éphémère (cf Biennale de design) avant de trouver ses formes privilégiées et stables. La nuit commence sous la dalle (de manière péjorative dans la pénombre des parkings) et se termine dans les tours (comme sculpture célébrant les grandes enseignes qui les occupent). C’est dans les espaces ouverts qu’elle est le moins caractérisée. Contraste entre la présence nocturne et la réalité des activités. L’unique boîte de nuit a fermé, la terrasse du toit de la Grande Arche ferme avec les horaires de bureaux, les cafés tirent le rideau plus tôt que dans Paris et aucun n’est conçu pour une sociabilité nocturne… Les personnels nocturnes d’entretien sont par exemple complètement exclu de l’urbanité de la Défense.
Faire évoluer la notion d’art dans l’espace public, et plus largement celle du mobilier : vers la ville 2.0 et des modes d’appropriation partagés/interactifs : la dalle est une scène extraordinaire, il faut continuer à développer sa capacité à accueillir des pratiques culturelles vivantes. Moins que d’édifier des œuvres sur le mode unique de la sculpture, peut-être faut-il aller vers une mise en scène artistique des dimensions (Prisme) de ces espaces publics pour y faire surgir des pratiques ou des significations artistiques. La dimension nocturne de certaines œuvres pourrait s’inscrire dans le devenir nocturne de la Défense, ainsi que dans les réflexions sur les évolutions ville 2.0.

Une vision pour l’espace public

1. retrouver le sol
> créer des seuils urbains mixtes organisés autour des mobilités douces au niveau du sol facilitant les cheminements et circulations, à proximité d’espaces à l’air libre (entrée, bord de dalle),
> le seuil central se trouve à la croisée des axes reliant Courbevoie et Puteaux.
> repenser la mobilité dans les sous-sols et dans les voies couvertes
>proposer des espaces d’échange de mobilité (parking vélo, espace de dépose de logistique de proximité, espace de stockage pour les habitant)
> faciliter  les circulations et qualifier les accès aux rez-de-dalle
2. re-grand axe
> réaffirmer le caractère exceptionnel du grand axe de la Défense et redéfinir ses séquences (les jardins de l’arche, le parvis, le coeur, le bois enchanté, la tête vers la seine)
> aménager des axes de liaison privilégiée vers les villes (courbevoie, puteaux, nanterre et neuilly) depuis le grand axe

3. re-habiter le domaine
> réveler un potentiel très important de réaffectation d’espaces en cœur de dalle (plusieurs dizaines de milliers de mètres carrés) ainsi que le long des façades de la dalle, généralement aveugles
> exploiter les volumes existants dans la dalle pour des  nouvelles activités innovantes
> rétablir une relation urbaine avec les rues bordant le site
> proposer des programmations et des petites surfaces peu disponibles sur le périmètre du quartier

4. nature invasion
> créer de nombreux liens « verts » sur et autour de la Défense
> développer les zones de nature dans les quartiers et sur le grand axe
> connecter le site à la trame existante dans les villes alentours
> planter mieux et différemment sur la dalle
> décliner l’idée de nature (nature nocturne, nature éphémère, hypernature …) pour mieux l’adapter aux différents temps du site