Separating the two entities allows for budgetary flexibility by enabling them to be built independently of each other, in two distinct phases.

The New Gymnasium

As part of the redefinition of a sports center to the north of the Béthusy secondary school, the new gymnasium naturally positions itself in the vicinity of the existing gyms. In fact, this approach expresses the desire to free up its eastern facade, liberating it from the "oppressive" encroachment caused by the current blank facade to be demolished. Refurbishing the exterior extension of this façade not only gives a new dimension to the existing gym, but also advocates for a dialogue with the all-weather area, acting as an invitation. The fact that it is partially buried helps to integrate it into the site, and logically closes off the sports area.

The APEMS

The location of the space intended for the day reception of local students, in particular from the Mon-Repos school located at the south of the Béthusy site, suggests a deliberate preference to be at the heart of the site. Indeed, the strategic choice of location demonstrates the appropriateness of the gesture through the possibilities it creates: firstly, convergence from all sides, and secondly, its integration into the slope. The fact that the building disappears into the ground with its accessible green roof has the advantage of offering an outdoor space linked to this entity and meets the need for incorporation into a built-up site, which, moreover, is representative of different architectural periods.

The Volumetrics of the New Gymnasium

Following a search for the right shape, the choice of a semi-subterranean rectangular parallelepiped is an obvious choice, not only to compensate for the oversized height required by the competition programme (badmington height 9.00 m), but also to make it easier to assimilate in a pre-established context. It should be noted that the interior dimensions of the gym itself consider a 1-metre reserve around its perimeter, so that it can be officially approved to Swiss Sports Federation standards if required.

Volumetrics of the APEMS

Keeping in line with a quest for aesthetic perfection, and in order to optimize not only its integration into the built fabric, but also to create the necessary link by means of a ramp between the main building's courtyard, which itself interfaces with all accesses to the running, shot-put and long-jump tracks located to the north of the site, the choice of a rectangular parallelepiped buried in the ground was imperative, thereby validating the overriding intention of assimilating the building into the intimacy of a pre-existing environment.

The Architectural Choice of Structures

The New Gymnasium and the APEMS

In order to create uniformity and mark the intervention of our time in a built context, the choice fell on a simple, clear, rigorous and similar design in both entities, namely: concrete for everything that is buried or in direct contact with the ground and timber structures for what is built above ground, the spirit being to use timber from the forests of the City of Lausanne, thus benefiting from a local supply and significantly shortening execution times.

For the gymnastics hall, the decision to transfer the structure to the outside of the building confirms this approach, while at the same time offering the opportunity to free up as much of the hall's ceiling as possible. Regarding the large buildings, the need to oversize the frames in the eastern zone is felt to be an obvious necessity to enter a dialogue with them. In contrast, the western part of these superstructures is slimmed down and lightened to better harmonize with the existing gym no. 2. The result is an asymmetrical superstructure whose momentum expresses the dynamic vitality required for the practice of all sports.

In the case of the APEMS, the mix of concrete and wood is based on the same principle as that of the gymnasium. However, it should be emphasized that the entire rear section of the building, from the ground level to the top of the skylights, is made of concrete, whose function is similar to that of a retaining wall, to absorb all the loads inherent in its location, facilitate its installation and optimize its impermeability.

Materialization of the Project

Envelope Performance

The choice of the facades was dictated not only by aesthetics, but also by the performance of the chosen system. The adoption of the Lucido ® concept, which is perfectly suited for this project, gives the building envelopes a unique appearance. This active façade cleverly combines wood and glass, reducing heating consumption by around 80%. Furthermore, the system ensures the mastery of all thermal bridges (i.e. that all thermal bridges are eliminated).

As for its appearance, it should be emphasized that this envelope has an exceptional and spectacular character, reflecting the ambience of the context it presents not only to the rhythm of the seasons, but also with respect to light and weather conditions.

To ensure that no energy is lost, the foundations are made of properly insulated reinforced concrete whose composition guarantees 50% recycled concrete from a source within a 25 km radius (e.g. concrete supplied by Gravière de la Claie-aux-Moines).

For the absorbing elements of the system applied to the gym and APEMS, the wood chosen is "natural" Douglas wood, with the exception of the anthracite base cladding of the gym, which is planned along the same lines, but with a black-painted absorbent.

Choice of Wood Species

For most of the visible elements, i.e. the absorbing elements of the active facades, the wooden parts of the exterior carpentry, the uprights making up the visible interior structure, and the acoustic panels embedded in the concrete of the gymnasium, the choice fell on Douglas wood, a species available in the forests of the City of Lausanne.

Choice of Green Roofs and Tree Planting

In accordance with the wishes of the Parks and Promenades Department, as expressed in the competition specifications, and because it's a simple and economical way of embellishing the city while creating additional green surfaces, thereby facilitating its integration into an already built environment, the roofs of the gym and ancillary premises are " extensively " vegetated, i.e. not passable. The roof of the APEMS, on the other hand, is "intensive", as it is accessible and planted with trees.

Furthermore, the choice of vegetated roofs not only optimizes thermal and acoustic protection, but also offers the possibility of using fresh water for outdoor irrigation.

Acoustics and Light

The acoustic requirements are ensured by wooden walls (Douglas wood) inserted into the concrete in the lower part of the gym. In terms of light, a minimum of 50% natural light (300 LUX) is required to cover lighting needs in the living areas. The provision of natural light has been optimized as far as possible, while meeting Minergie ECO criteria and the recommendations for sports halls issued by the Department of Physical Education and Sport.

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