Barkow Leibinger Architekten

Cosandey Square Experimental pavilion at EPFL . Lausanne

Barkow Leibinger Architekten

The cultural and art/ exhibition spaces are located below ground day lit by two gently ramped courtyards for outdoor display, presentations, talks, or lounging.

This position has two advantages: first, these spaces function independently
and with opening times while at the same time connect internally
by way of the large open spiral stair, elevators or security stairs. Secondly the
underground level lowers the overall height of the building and thereby also
making wood construction above-ground allowable. The lower level is concrete
construction which allows for good environmental controls (heating cooling,
humidity). Large flexible gallery spaces are complimented by service and storage
and an open foyer, which allows for views and transparency across the
lower level from south courtyard to north offering daylight from two sides.
The ground and first floor are given over to the Montreux Jazz Lab and entrance
foyer. A double height jazz performance space is located at the south to
the Place Cosandey, which can connect and expand into a café/ bar space or
open out to the exterior. The restaurant is located at the first floor level offering
additional open or glassed-in views to the double height performance space
and stage and also opens out to the surrounding exterior terraces. This is a
casual and expansive space and as reflected by the materials and surfaces
which define it.
The building entrance faces the Campus Esplanade and to the east along the
diagonal pedestrian circulation between the Esplandae and RLC. Urbanistically
the concave exterior walls project a shallow “cupped” space to each of the
cardinal points they face frontally. A service entrance is located on the ground
level facing the Allée de Savoie.
The “Welcom” pavilion at the top level is located where the best views and
more reflective/ quiet spaces for visitors or VIPs are. Also included on this level
are a large conference room and also an atelier for an artist. As in the lower
levels a series of exterior terraces offer views and additional exhibition or meeting
spaces. As in other levels the column free interiors allow for a range of
differing possibilities for exhibition layouts. This upper level also has the added
benefit of roof skylights for additional daylight at the exhibition spaces and for
the large open circular public stair.
We selected wood construction for the upper levels for its sustainability, speed,
and flexibility. The floor slabs are made of wood glu-laminated beams fastened
to lightweight concrete slabs to provide a hybrid long spanning structural system
with the benefit of cantilevers at the perimeter for roofed over exterior
spaces that are visually light blocking less light and view from neighboring buildings
and approaches. The exterior terraces are constructed of wood beams
with lighter wood decking at the cantilevers. The pattern of the floor beams is
a radially woven net spanning from the exterior wall-beams to the central core
from 10-13 meters visible from the interior spaces and terraces. The concave
wood wall-beams are punctuated where necessary by wood framed glazing
and doors. This is a structural system that favors pre-fabrication and speed of
construction.
The combination of form, space, material, and structure is intended to
give the new pavilion a strong visual identity on campus. It will be a dynamic
experiential place to serving as a crossroads within the campus
of the EPFL. The building will be both progressive in its use of material
and technology, forward looking, flexible and accommodating.

Description of structural system
The new pavilion building of the EPFL has three floors above and
one below floor and will provide areas for exhibition, restaurant and
performances and meeting rooms.
The slabs consist of timber/concrete composite girders, which span
between the central core and the load bearing façade. This ensures
column free rooms for maximum flexibility of utilisation. After having
arranged glued-laminated timber girders (section 30x80 cm),
5 cm thick precast concrete elements will be put on the timber
girders. Additional 7 cm concrete will be poured on site, in order to
gain a concrete plate of 12 cm thickness. To ensure the composite
behaviour between girders and plate, shear plates will be glued into
slots on the top of the timber girders, which transfer shear forces
between both structural elements.
The big advantage of those composite girders is the compliance
with vibration requirements as well as building physic requirements.
Instead of only pouring huge masses of screed onto a pure
timber structure to ensure acoustic, fire protection and vibration
requirements, it is much more economic to use those masses as a
part of the main structure. Additional heavy non bearing floor layers
could be avoided by this system.
The spans of those composite girders vary between 10 to 13 meters
and can reach up to 17 meters on corner areas. The girders act
as a single-span system plus cantilever, which gives support to the
balcony areas. On those areas the concrete plate will be replaced
by a timber deck, as here the above mentioned building physic requirements
are not decisive.
Not at least for geometrical reasons, but also to reflect the structural
strains, close to the slab edges the timber girders are being
divided into multiple smaller girders. This leads to an impressive
view of the slab itself.
The curved façade wall elements consist of a framework of timber
posts and transoms. Those walls take the loads of the slab and
transfer them to the walls below. As the walls do not stand directly
above each other, they will be executed as curved deep beams. The
support of each deep beam is located directly on the intersection
points between two beams, which are above each other. To guarantee
the load transfer within the deep beam, diagonals between the
posts are arranged and connected with the top and bottom transom
via slotted plates and bolts.
The level below ground floor will be done as a concrete structure.
Columns give support to the timber walls of the ground floor level.
The whole storey will be enveloped by 25 cm thick concrete walls.
As the gravity loads of the whole building is comparatively less,
strip and isolated foundations will be carried out. This allows for a
thin and economic base plate.