Text description provided by the architects. The buildings were designed as the firsts prototypes in order to explore tree different conditions at the same time. (Prototypes and not a final construction, in order to keep searching and improving these ideas in the future).
1) One single mass as façade (Performance)
PROTOYPE 1 AND 2 (COSTANERA LYON 1 AND 2) were designed in order to negate the typical curtain wall building typology. Using the structure as a single mass with an excellent passive design, easy to heat or cool without adding a double skin or consuming a lot of energy.
2) Design process as facade. (Evidence)
PROTYPE 1 (COSTANERA LYON 1) design process was interrupted by a special request of the developers. They wanted to have an office penthouse with a swimming pool with an excellent view on the top of their office. A new program that required more square meters.
In order to create this new space, a piece of the building was taken from the most visible corner and where moved up to the roof. The corner disappearance in the façade became a record of the design process.
PROTYPE 2 (COSTANERA LYON 2) was forced to use cantilever slabs in order to maximize all the square meters of the given site. The proposed cantilever slabs didn’t worked under gravitational and seismic forces. The solution was to add a series of perimetral walls in order to provide torsional rigidity to the structure. In order to allow more views from inside the walls became a series of Vierendeel beams that carry the dead load weight of the building trough the façade. The building was rethought and designed as an essay of prefabricated elements: 21 Vierendeel beams, 16 slabs, 1 core and 14 scissor base columns.
Because of Chile seismic condition is highly recommended to build the prototype 2 as one piece. The façade became a paradox of two opposite ideas, one reinforced concrete form that really works as a house of cards; if one element is removed the whole building will collapse.
3) Structural logic as façade (Tectonic)
IN PROTYPE 1 (COSTANERA LYON 1) most of the columns were releases from the interior of the offices in order to allow more flexibility for the users and optimize the structure as thermal mass on the facade.
After a piece of the building was taken from the corner the envelope became a composite structure, comprising a rigid core of reinforced concrete walls wrapped in a bracing structure that support the front over the void in the corner. A legible path of vertical and seismic loads to the foundations.
IN PROTYPE 2 (COSTANERA LYON 2) all the columns were release from the interior of the offices. The structure was designed by stacking a series of Vierendeel beams on the façade. Vertical and seismic loads works trough a system of Viernedeel beams that created and non-deformable geometry. A system that optimize the mass and provide the right amount of torsional rigidity with a perfect balance of solid and voids to create comfortable interior spaces.
Both exposed structures became legible façades that everyone can read from the exterior and work as an excellent thermal mass.