The Lacassagne telephone exchange is an emblematic building in the Part-Dieu district of Lyon. Built in 1972 by André Gutton, architect of public buildings and national monuments since the 1930s, it is part of the Orange group’s technical heritage. The operation to unite the regional staff of central–eastern France plans for the accommodation of 2,000 people on this unifying site.
The project by practices Hardel Le Bihan Architects and HGA-Hubert Godet Architects positions this remarkable building at the centre of the new Orange Campus, functioning efficiently to connect the three buildings (the existing exchange with its two new extensions) and opening up views from and towards each of these for maximum transparency with the city and to maximise light. From an urban point of view, the project complies with plans for the urban renewal of the Part-Dieu district established by the AUC, respecting the original building. Positioned on the south-western edge of the district and seen from the train tracks and the wider landscape, the development forms a powerful landmark as a mark of this renewal.
The Lacassagne exchange naturally orchestrates the corner plot, freeing up two open spaces to the north and the south.
The extension, composed of two buildings, is inserted, highlighting the urban alignments and unifying the site. The three entities are linked by the agora, a broad internal street running across, through the ground floor of the exchange. Footbridges provide links between the upper floors.
“More than just circulation, the agora is a place for life, for exchange and socialising. Its 7m ceiling height makes it possible to install events spaces for public receptions,» explains Elodie Vuarchet (HGA). A showroom, an auditorium, but also several meeting rooms, the cafeteria, the concierge, «all of these spaces are visually connected with the garden on the ground floor“.
“The more work methods turn to digital and digital connectivity, the more people need quality physical interactions. This is why we have given so much importance to the spaces used every day by the workers around and beyond their workstations,“ adds Cyrille Le Bihan (Hardel Le Bihan Architectes).
The connection and coherence between the new and existing constructions is seen in their massing and facade grids: the folding geometry and truncated slopes shape views, framing the historic exchange, while the slopes incorporate large planted terraces extending the floor plates. In a kinetic play of rhythm and light, the homogenous grid of the facades, in copper-coloured power-coated aluminium, creates a resonance with the brick envelope of the exchange, visible behind its concrete exoskeleton.
The Orange Campus is characterised by the durability of its constructive choices and materials. We sought to remain faithful to the geometric simplicity of the buildings already present in the Part-Dieu district, while enriching it with a dynamic constructive expression using materials and techniques that are in the continuity of the recent past.
Both on the site as a whole, as well as inside the buildings, the desire to provide a healthy, bright and airy environment is predominant. Openings are created between the buildings, while the distribution favours workspaces being close to daylight sources, benefiting from direct sunlight and open views out thanks to glazing panels that are 0.9m wide by 2.7m high. The staff restaurant and the showroom are given large glazed modules, which also enable maximum penetration of natural light.
In terms of air quality and thermal comfort (further details are provided in the fact sheet, see below), natural ventilation is ensured by comfort openings in each grid. Shading devices and the depth in the facades contribute to the control of solar gain, while the externally insulated concrete structure allows for thermal inertia. Users benefit from thermal comfort all year round thanks to a hydraulic distribution system within the buildings that takes into account their orientation: it is thereby possible to heat areas with the least sunlight, while cooling the facades that are most exposed to the sun.
On the roof, terrace gardens provide the vegetal continuity of the site, which is edged to the west by the Nelson Mandela Esplanade. Rainwater is captured and stored.
While the offices meet best international standards in terms of environmental quality and energy performance, they are above all agreeable to use and stimulating, open to the outside and propitious to exchange.
