Gulliver cantilevers over the DOX Centre for Contemporary Art, in Prague
Aleš Jungmann Gulliver cantilevers over the DOX Centre for Contemporary Art, in Prague

A wooden zeppelin looms over the stark white roofs of the Dox Centre for Contemporary Art, in Prague, cantilevering more than 50 feet beyond one of the cultural center’s warehouse-like buildings. As fantastical as it appears, the 130-foot-long, 30-foot-diameter structure known as Gulliver is in fact not an airship, but an elevated event space and pedestrian bridge that incorporates stadium seating and a stage for literary events and lectures.

Gulliver is the brainchild of Dox Centre founder and director Leoš Válka, who for years harbored a desire to “invade” the Dox with a “parasitic” structure with “an absurdly fascinating organic shape that would contrast with the Dox Centre’s existing architecture,” he said in a statement. In 2013, Válka asked Martin Rajniš, co-founder of local firm Huť Architektury Martin Rajniš (HAMR) to design him such a space. “I didn’t hesitate,” Rajniš says.

Rajniš sketched what he describes as “a soft space defined by a wooden structure made out of unrefined wooden branch sticks, in utter contrast to the strict white cubic volumes of the Dox.” He showed his sketches to Válka, who initially loved them but, 24 hours later, had a change of heart. “ ‘This has to be different,’ ” Rajniš recalls Válka saying. “ 'Let’s draw an airship—but not just any airship. Let’s draw one that fulfills all the dreams of 12-year-old boys!' ”

Válka drew a long blimp form spanning from one building to the other, extending over the Dox Centre’s courtyard and angled slightly, as if about to land. “I was amazed,” Rajniš says. “Needless to say, when I feel that someone else's idea is great, I gladly join.”

David Kubik
David Kubik

HAMR partnered with Timber Design, a structural engineering firm in Česká Skalice, Czech Republic that specializes in timber construction, to create a freestanding steel structure that anchors into the ground and is encircled with 14 timber truss rings, forming the zeppelin’s skeleton.

Rajniš, who draws everything by hand (“I don’t own a computer and never will—all the software I need is in my head”), originally wanted to forgo the steel frame but load tests convinced him otherwise. “The wind force above the roofs of the center is very strong,” he says. “Generating enough resistance against horizontal wind forces to stop the structure from pivoting was difficult.”

Counter to Rajniš’ dismissal of software—his staff translates his drawings into 3D models—Timber Design structural engineer Zbyněk Šrůtek embraces digital technology and used Dlubal Software’s RFEM to model the structure’s steel, timber, and ETFE elements. He worked with Rajniš to ensure the structural components would not detract from the “illusion of flight.” Thus, Gulliver’s two white-painted steel truss support columns, rising 65 feet and 54 feet from the concrete foundation, tuck against the neighboring Dox Centre buildings connected by the zeppelin. To address the high wind load, the designers also ran a 7-inch-diameter steel tube from the front of the airship to the building, creating a third anchor point.

The 30-foot-diameter glulam larch wood truss rings, whose top and bottom chords are 4.7 inches wide by 3 inches deep, are connected by roughly 2-foot-long wood web members, also 4.7 inches wide. In the longitudinal direction, similarly constructed wood truss beams stiffen the structure with the help of steel cables, and provide the base for a shell of 3-inch-wide, 1-inch-thick curved wood laths spaced every 20 inches. These laths support the airship’s exterior lamella, 0.75-inch-thick slats that range between 1.85 inches to 2.5 inches wide. To protect the unfinished lamella, the architects added a curved roof of transparent, mechanically stretched ETFE (ethylene tetrafluoroethylene).

Aleš Jungmann
Aleš Jungmann

Concocting this structural puzzle took two years, Šrůtek says. Timber Design also oversaw Gulliver’s fabrication and construction. “Special CAD systems for steel and timber with the possibility of data export to CNC machines were used,” Šrůtek says. His team built a full-scale mock-up of one of the circular truss rings to test all of the connections, including the custom brackets that anchor the steel cable system.

The circular timber truss rings arrived at the construction site broken down into three arcs each. First, workers erected the steel framework and then secured the truss rings with steel plates and high-strength screws. Next, they constructed the nose and tail of the airship and craned them into place. Finally, they screwed the lamellae into the shell and the ETFE diaphragm added via steel ribs that are also secured with bolts and steel cables.

Gulliver was completed in late 2016. For its opening, the Dox Centre brought in a number of celebrated authors for readings and a discussion, and mounted an exhibition about the airship’s inception, design, and construction.

Rajniš and Šrůtek are both proud that the project was designed, fabricated, and built completely within the Czech Republic. It showcases the country’s talent, Šrůtek says. “Having the opportunity to design and then manufacture and build an exceptional construction where wood is statically used to its limit of possibilities, in the amazing atmosphere of the gallery, was a very powerful driving force for the whole project,” he says. “It was a very beautiful three years of my life.”

For Rajniš, Gulliver is a testament to the power of collaboration. “I work with the stars and rising stars of the youngest generation,” he says. “I would recommend it to anyone."

This article has been updated since first publication.