The two simple concrete boxes that serve as gallery space for Israel’s new Design Museum Holon, designed by Ron Arad Associates (RAA), are enveloped in a massive, 300-ton sculpture that is itself a kind of building.
Known for pushing materials to their limits, RAA enlisted the help of former Arup engineer Giacomo Sordi to wrap five bands of Cor-Ten steel around and between the galleries in the whimsical manner of the London firm’s furniture. “We work seamlessly between the disciplines of architecture and product design without distinguishing between them,” says Asa Bruno, co-director of the 10-person architecture group within RAA. The $16 million, 44,000-square-foot project—located in Holon, just south of Tel Aviv—opened in January 2010.
Fabricated in Bergamo, Italy, the Cor-Ten bands were shipped in 40-foot-long segments that filled 99 shipping containers. The total combined length of the bands exceeds half a mile, while the height of each band ranges from 4 feet to 8 feet. Unlike the solid steel sheets used by the artist Richard Serra, the Holon bands are for the most part 20-inch-wide hollow ducts welded together from ¼-inch-thick panels. (“The welder,” notes Bruno, “was a very thin guy.”)
A variety of structural solutions enables the bands to twist and turn with elastic continuity. Internal cross-ribbing stiffens the hollow segments, which account for two-thirds of the total band structure. Peeling away from the galleries, these free-flying spans and cantilevers enfold outdoor circulation spaces. The spectacular central loop, for example, soars 100 linear feet before touching down to connect with the foundation. Disappearing momentarily underground as it hugs hidden concrete anchors, the bottom band re-emerges and lifts off, once again hollow, several yards further along.
Where the self-supporting segments blur invisibly with those on the ground—which in some areas are pure surface ornament bolted to both sides of a concrete wall—smooth, factory-cast concrete armatures mediate the discrepancy between the steel bands’ low dimensional tolerance (1/10 of an inch) and the tenfold higher tolerance of the site-poured concrete. “When you stare at the building,” says Bruno, “there is no way to know what is cladding and what is not.”
In addition to form, color and texture define the steel’s expressive character. After sandblasting to clean the bands’ surfaces, the Cor-Ten was left outdoors to weather for up to three months and periodically soaked with hydrochloric acid, which accelerated the process. Specially formulated oil-based weathering paints that soak into the depth of the steel, in earth tones from rusty orange to dusky purple, differentiate the bands like layered rock strata. A final coating, applied on site, heightened color definition.
The RAA team embraces the inevitability of further weathering as well as the traces of internal welds that remain visible. “The idea was not to imply a state of finished perfection,” says Bruno. “We like all the marks and scars and history inherent in the material.”