What is unique about Smithsonian museums

Wavy glass roof for the Smithsonian Museum

The inner courtyard of the Smithsonian Museum, one of the largest American museums, was roofed at a height of 27 m according to plans by the architect Norman Foster. The museum gains a year-round usable area for events and concerts. The steel and glass roof was planned and manufactured by Josef Gartner GmbH in Gundelfingen an der Donau.

The Smithsonian Museum in Washington is located in the building of the former American Patent Office. Today the building complex houses, among other things. the American Art Museum, one of the main museums of the Smithsonian Institution, and the National Portrait Gallery. With 18 museums and galleries mainly in Washington, Smithsonian unites the largest museum complex in the world. The former patent office building is named after its most important private sponsor, the Donald W. Reynolds Center for American Art and Portraiture. The covered courtyard, which is used for jazz concerts and other events, was named after the Washington donor couple Robert and Arlene Kogod. Before the renovation, the open courtyard could only be used a few weeks a year, as it was often too cold or too hot. A landscape with trees, fountains and watercourses has now been created under the glass roof. Gartner engineers built the roof in such a way that it protects against sun glare and offers good acoustics. This allows guests to visit restaurants and events both in summer and in winter.

Gartner formed the waves with steel profiles and bridged great distances. Every element of the roof structure is unique and was designed three-dimensionally on the computer at Gartner. The complex geometry and the small tolerances made extraordinary demands on the design, manufacture and assembly. The entire construction has a footprint of 39 mx 84 m and consists of welded, twisted steel girders with a height of up to 1 m. The individual elements with different sizes of approx. 4 m x 10 m were prefabricated in Gundelfingen. The roof is deposited on only eight steel supports as it was not supported by the existing buildings. The steel supports were made from steel tubes with a diameter of 850 mm. The roof structure was connected to the supports via a special cast head. The roof is drained in the supports through drainage pipes. Only recent developments in computer design made it possible for Gartner to implement Foster's sophisticated design. Gartner engineers in Gundelfingen designed the construction on the computer using 3-D graphics software. It was then made to fit precisely in our own steel construction. Around 120 individually shaped steel frames, each weighing around 8 t, form the grid for the glass. A total of 860 glasses are built into these frames. The roof weighs approx. 800 t and the supports approx. 200 t.

A total of 7,000 individual elements were developed and manufactured. Glass with a low iron oxide content minimizes the color dispersion of natural light. This prevents excessive heat build-up in summer and the formation of condensation in winter. Overall, the effort for air conditioning is reduced. After labeling the individual parts, Gartner shipped the elements to the USA and transported the several-tonne parts to the construction site on large vans. There they were put together again, taking into account the small tolerances of the three-dimensional construction.