The Broad, philanthropists Eli and Edythe Broad’s contemporary art museum rising on Grand Avenue downtown, is the most significant new architectural project in Los Angeles. The three-story, 120,000-square-foot building, designed by Diller Scofidio + Renfro (Gensler is the Executive Architect), topped out on January 8, and by next year will be home to the Broads’ collection of more than two thousand contemporary artworks.
Project Manager Greg Wade, who works for the museum’s general contractor, MATT Construction, recently walked me through the site.
Perhaps the project’s most important element is a 65-foot-long, 1.5 foot-wide, 2-inch thick, V-shaped member of built-up structural steel plate that resembles the hull of a Viking ship. It’s called the “touchdown beam,” and, once installed, will bear the load of the entire “veil.” The veil encompasses the steel and GFRC (Glass Fiber Reinforced Concrete) lattice that will front the museum.
At the time of this writing, the beam sat a few feet from the building, awaiting relocation to the Grand Avenue side. The 83,000-pound beam, shipped in one piece from Germany, will be set in place with a 500-ton hydrocrane.
When DS+R first conceived of the veil—originally designed to be precast concrete—it was meant to support the weight of the museum’s roof. That plan was scrapped, however, because the cost and complexity of supporting that much weight with no structural steel would have been too high, said Wade. The touchdown beam would also have had to be so large that it would block much of the sidewalk. Instead, the beam will now fit handily below grade so the veil will appear to emerge from the concrete.
The veil, which soon will be covered with hundreds of molded GFRC panels, has been the object of close coordination between the architects and the builders. The architects have been working in the 3-D design software CATIA, which has been translated into Revit and AutoCAD 3D for the builders. Sometimes the shape hasn’t matched what the architects wanted, so it’s been changed, said Wade. Other times the shape hasn’t matched what the builders needed, so it’s been changed again. This back and forth, the project manager claimed, has constituted the most interaction he’s ever had with an architect.
The second floor of the building cantilevers 60 feet from the building’s core toward Grand Avenue. In the center of this floor will be the vault, which will contain the artworks not on display in the galleries. To install this cantilever, the builders teamed with geotechnical and mining specialists DYWIDAG Systems International, creating a post-tensioned structure more akin to a bridge than a building. The slab was raised via a gigantic hydraulic jack, employing about 300,000 pounds of force. It measures six feet thick near the building and just two feet thick at its end.
The top floor will contain the bulk of the museum’s exhibition space. A diagrid steel matrix frames the roof. It will soon be given a curvy GFRG (Glass Fiber Reinforced Gypsum) cladding, resembling the veil, and will be inset with 399 glass skylights, all angled to face north, to create a glowing, rhythmic effect.
MATT Construction made mock-ups of many of the building’s systems before beginning construction. A dozen were required by contract, but the firm made almost 100 to determine various components’ constructability. “Until you start to build, you really don’t know what will work,” said Wade.