Paul Klee Center
The steel ribs, clad with stainless steel, blend in with the patterns found in the surrounding fields.
Located on the outskirts of the city of Bern, the Zentrum Paul Klee, with the Alps as background, is articulated around three artificial hills: the central hill containing the exhibition section, the north hill housing a multifunctional room, an auditorium and a children´s museum, and the south hill, a space reserved for research and management activities.
The majority of the works that form the museum´s collection cannot be exhibited for reasons of preservation but they will be made available to researchers. To ensure the optimum preservation conditions, this museum will not benefit from zenital light, but it will be illuminated from the west façade, through which light will be filtered by a system of translucent screens, creating softer light.
Elevated on the land slope, the three hills are mutually chained like three waves, their undulation decreasing with the building elevation and their span being partially below the ground level. These wave-like spaces are interconnected by a covered passageway. The undulation is transposed in a continuous way from one end of the building to the other under a roof that is clad using Uginox Top, a matt-finished stainless steel product. Taking into consideration the roof´s geometry, 0.4 mm-thick stainless steel sheets have been modelled in the mill before been installed on a wood structure.
The structure, which intentionally remains visible both from the inside and from the outside, is formed by a series of parallel steel arches, whose pieces, produced by means of CNC equipment, have been manually welded. Steel was found to be only material to provide an adequate response to the largely different stresses, as it allows variations in the plate thicknesses without changing material sections.
High variations exist in the arches´ height/span ratio, depending on the point considered in each case. The reinforced concrete support points allow standing horizontal forces in collaboration with the floor slabs. Two series of tie rods guarantee the cross-sectional stability of the arches: in their top arch section, 48 mm-section tubes are used to support the lattice elements, whereas in the bottom section HEB 140 are employed. The thermal insulating material has been placed under the tubes so that these remain visible.
Façades absorb any roof deformation caused by exploitation loads and temperature variations. A 6.5 m-span overhang, fabricated with HEB160, is suspended from the roof by cables and is supported on the stanchions of the bottom section of the façade, i.e., two flat-rolled steel plates.
Stainless steel advantages:
- A suitable aspect for this type of contemporary architecture
- A low thermal expansion coefficient allows the installation of continuous sheet lengths up to 20 m
- Easy implemantation allowing a perfect fit of the curvature of the roof
- High mechanical properties for an equivalent resistance to a given effort, allowing the use of small thickness (0.4 mm in this case).