Aarau’s new bus terminal, Aarau, Switzerland

The new bus terminal roof in Aarau undoubtedly leaves a mark on the redesigned station square. Its curved shape leaving a clear view to the sky in its centre does not to limit the space towards the top, but welcomes the travellers in a bright and friendly environment.

Swiss architects Vehovar & Jauslin together with the engineers of the German company formTL were looking for a very light, translucent material, in order to create a spatial atmosphere, which is similar to that of a forest glade.

The pneumatic structure of one large ETFE foil cushion perfectly meets these requirements. An inner free-form steel table supports the two membranes. The cushion’s adaptive air pressure is maintained by a ventilation system, while an irregular network of steel cables on both outer sides controls its shape. The pipes for drainage, lighting, air supply and sensor technology are hidden in the load bearing structure. Consequently, the roof does not celebrate the technical parts but its lightness and airiness.

The planners chose blue coloration of the upper membrane, in order to provide a permanent feeling of blue sky for the waiting passengers. The team specially developed slightly different, seamless printing patterns for the blue upper and the clear lower film. As a result the structure of the whole roof can be seen from underneath, while the patterns provide shade and prevent unwanted emission of direct artificial light into the night sky.