Lunar Dome, USA

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Tent Supporting Structure with Arch Trusses

Dlubal customer formTL provided the structural engineering for this project. The finite element software RFEM was utilized for the analysis and design.

The tent was created as a temporary structure, optimized for quick assembly and easy transport A main membrane, supported by four truss arches, an elastically supported projection dome, and a large ETFE facade form the interior open space for this structure. The flexible foundation includes adaptable footing elements, anchored with long dowels. Pasadena, California was the first stop for the traveling theater for "Apollo 11 - the Immersive Live Show" in the summer of 2019.

Structure

The Apollo Theater’s main structure is formed by 4 arch trusses. Hanging from these elements is an approximate 52,743 ft² membrane made of PVC-coated polyester fabric type III. The two slightly inclined center trusses carry the primary load of the 240-foot-long tent structure. These main trusses have a span of 183 ft and a height of 89 ft. The 36-foot-high smaller lateral trusses in the foyer and backstage area are set at a higher inclination.

The interior includes a projection dome above a surrounding timber wall. This dome has a diameter of 151 ft and a height of 49 ft. It is suspended from the two main arches with elastic cables. This suspension stiffness is extremely low to allow the prestressing force to change only slightly if the outer shell is deformed (for example, due to strong wind). The projection dome membrane consists of lightweight PVC-coated polyester fabric with micro-perforations, which absorbs about 65% of the sound.

Located under the foyer arch are 32-foot-long facade supports with an ETFE cushion covering. The columns resist pressure loads only from the foyer arch. In the case of uplift loads, elongated holes provide decoupling.

The foundation for the arches includes large steel plates with 2.36 x 78.74-inch piles. The plates can be used to compensate for height differences up to 19.69 inches. The piles were designed according to EN 13782 and verified in a pullout test.

Within one short year, the planning, production, and assembly of an unmatched temporary tent structure were completed.