Building with Air at the AIR MUSEUM Amberg April 26

Swiss Architectural firm Vehovar & Jauslin Architektur together with German lightweight structure engineering company FormTL have recently unveiled the largest air-supported single-chamber membrane air cushion in the Swiss town of Aarau. It is the roof of the Bus Terminal and Train Station Square, the world’s largest air-supported single-chamber membrane air cushion.

Schlosshof Dresden (c) Juergen Loesel

The Air Museum in Amberg has decided to dedicate a special exhibition called Building with Air to the development of this fascinating structure and the technology behind it and also presents additional examples of how air can be used as a building material.

When the word “air” is used in connection with construction, very few probably think of longevity. But in reality, air pressed into airtight envelopes/shells is an extremely cost-effective and sustainable building material.

The brand new central bus station in the Swiss town of Aarau proves that this does not only apply to temporary structures: its roof covers more than one thousand square meters and the structure is made of a steel frame and an air-supported membrane cushion.

It started with a search to find the lightest possible construction and the desire for an amorphous form. The roof is not intended to evoke a hall, but offers instead a pleasant place for the many commuters who transfer between train and bus every day to wait. After eight years of planning and only one year of construction, what has emerged is more than just a technologically pioneering masterpiece of urban architecture: the roof over the bus terminal, a canopy that the locals already affectionately call the “cloud.” Its organic shape with a clear view to the sky at its center originates from the desire to not place an upper limit on the square, but to welcome travelers in a friendly and bright environment. “From the beginning, we wanted to create a spatial atmosphere under the roof that resembles a clearing in the woods. “In order to greet the passengers in a bright and friendly environment, a very light, diaphanous material was selected” , explains architect Mateja Vehovar from the Zurich firm Vehovar & Jauslin. “We chose an air-supported membrane cushion made of the synthetic material ETFE. Such membrane roofs are not only easily designed in various forms, but are also extremely light, durable, weather-resistant and self-cleaning. The expansive cushion is held up from within by a freeform steel construction. An irregular network of steel cables across the outer surfaces gives form to the air cushion. For all the materials used, we paid attention to the issue of sustainability."

This also holds true for the air recirculation system: “Thanks to the excellent air tight quality of the cushion construction, the task of the ventilation system is nearly limited to solely adjusting the air pressure in the roof to suit the changing weather conditions” explains Gerd Schmid from the Radolfzell engineering firm formTL, which was responsible for the structural and technical design of the roof.

Finmeccanica (c) Cristian Guizzo

The world’s largest membrane air cushion represents a unique mixture of functional, advanced technology and a varied, delightful play with people’s sensory perception. It is more than just a mere bus terminal, it is functional art in urban space – a symbol for Aarau.

Aarhus (c) Quintin Lake

As part of their special exhibit Building with Air, the AIR MUSEUM in Amberg is presenting the development of this impressive structure. Models, material samples, movies and photographs offer an exciting look behind the scenes.

A retrospective about the ten-year history of formTL complements the exhibition with additional, fascinating examples. With their conversion of the CargoLifter hangar and the design for the Modern Tea House with Kengo Kuma, the engineers from Radolfzell have acquired an international reputation for themselves as specialists for lightweight structures.