Bâtiment I Confluence
The Health Hub is located in the Confluence 2 Urban Development Zone (ZAC 2), managed by SPL Lyon Confluence in Lyon's 2nd arrondissement. Based on a master plan for the ZAC produced by the Herzog & De Meuron agency, the urban planners at Atelier Ruelle then developed the individual plot specifications and designed the neighborhood's public spaces. Within this framework, the overall Sollys project, developed by Bouygues Immobilier and Linkcity, takes place. It comprises 11 buildings across three blocks, coordinated by David Chipperfield Architects.
Located in the heart of the "Health and Well-being" block garden in the Confluence district, the Health Center stands out from the surrounding buildings with its unique architecture. This architecture combines a gray-green tinted prefabricated concrete frame envelope with an internal timber structure (pine CLT panels and glulam posts and beams). This dichotomy creates a coherent response to the various architectural challenges of the building.
The gray-green prefabricated concrete facade is a comprehensive architectural solution to the challenges identified at the project's inception:
=> The building's facades rest on a series of large beams (100x180cm cross-section with an 18m span) that transfer the loads to the very localized load-bearing columns of the parking garage.
=> The dry construction method facilitated the project's execution with the parking lot remaining occupied (reduced noise pollution, cleanliness, and speed of execution).
=> The choice of concrete fully meets the requirements for mineral facades mandated by the urban development zone (ZAC), maintaining historical continuity with the architecture of the Lyon peninsula.
=> Straddling the parking lot's expansion joint, the building had to integrate this joint into its design. The choice of a prefabricated facade with defined joints renders this line invisible on the facade.
=> The gray-green tint allows the building to stand out within a surrounding context that favors the monochrome white palette desired by the architects Herzog & De Meuron. The building's public nature allowed for a departure from this rule, resulting in a building that is accessible to everyone.
=> The tint is achieved by adding green-tinted minerals to the concrete mix itself. This process ensures the longevity of the color and highlights the materiality of the concrete with its moiré patterns. The depth of the color obtained reacts fully to variations in light intensity throughout the day and the seasons, altering the gray-green palette.
=> The geometry of the prefabricated frames creates horizontal and vertical spines 70 cm deep. These form a thick facade in response to the need to control solar gain and guarantee the privacy of the consultation rooms in a building surrounded by office and residential buildings. The intensity of the shadows that travel across the facade during the day alters the perception of the building.
The wood used in the project also responds to technical and programmatic challenges:
=> The wood limited the carbon footprint of the construction of the health center.
=> The choice of wood was essential for the construction of CLT floors to lighten the building and limit load transfer to the parking area. The CLT slabs span from facade to facade with central supports on a glulam post-and-beam structure. The large dimensions allowed by CLT reduced the number of elements required.
=> CLT also enabled the floors to act as diaphragms, contributing to the building's stability and meeting seismic requirements related to the combination of the public parking area and the healthcare center.
Wood proved complementary to the prefabricated concrete facade, utilizing a dry construction method and geometric control.
=> The sensory impact of the wood visible inside contributes to the well-being of users, healthcare staff, and patients, fully meeting programmatic requirements (hygiene, acoustic and thermal comfort).
