The ancient Arabian sandstone colossi on display at the Asian Art Museum have remained remarkably well-intact for more than two millennia, but in present-day San Francisco, the 8-foot-tall, top-heavy figures are one strong earthquake away from certain ruin.
For the museum's mount maker, Vincent Avalos, necessity was the mother of invention. Avalos knew the towering figures involved in the “Roads of Arabia” special exhibition would be a challenge to protect even with the museum foundation's state-of-the-art base isolators, which greatly reduce seismic rumbling to help safeguard around 18,000 objects in the most valuable collection of Asian art outside of Asia.
“Everything in here is still going to shake during an earthquake,” Avalos said. “I didn't know what to do at first because when sculptures are this large, they start to approach architectural proportions. They'll start to approach the oscillating level of the building, because they have a tall center of gravity.”
The solution Avalos — the brother of Supervisor John Avalos — discovered isn't readily visible to the bustling patrons of the museum, but it could make all the difference: a thin-layered system of sliding plates under the base of the colossi's display podiums. The 2,000-pound, hulking muscular figures, thought to have once stood outside the temple of an ancient Arabian empire, would theoretically remain upright while sliding to and fro independently of the building's oscillation level.
The relatively new technology includes a nodular stainless-steel base that can slide along an upper polymer surface. The sliding plates are simply affixed into the bottom of a typical podium structure. EQX Global, a Napa-based company, retrofitted the plates specifically for the museum's display.
“People have been experimenting for years with roller bearings, ball bearings, things that would allow large objects to move during earthquakes,” said Paul Segas, co-founder of the company. “Our system is unique in that there are no moving parts, it's all based on the interface of the two plates.”
While San Francisco has long sought and implemented engineering solutions to prevent buildings from toppling, the concept of protecting critical objects within a structure is more common in earthquake-prone Japan. But Segas said events like the magnitude-6.0 Napa earthquake in August could help popularize the idea here, especially because of the untold millions worth of wine that spilled when barrels broke loose and
The Asian Art Museum is particularly keen to use innovative mitigation methods, at least in part because of its history with earthquakes. Once housed in a wing of the de Young Museum in Golden Gate Park, the ever-growing collection was eventually forced to find a new home when the de Young was damaged beyond repair by the magnitude-6.9 Loma Prieta quake in 1989, which marked its 25th anniversary last month.
Although temporary solutions kept the old de Young building open until 2000, plans were underway since the aftermath of Loma Prieta to convert the Civic Center's former main library into the new Asian Art Museum, thanks to private donations and a $42 million bond measure approved by San Francisco voters in 1994. The current site of the museum, decidedly less vulnerable to quakes, opened to the public in 2003.
Although no major damage was caused in The City by the recent Napa quake, the early-morning vibrations emanating from up north were enough to elicit thankfulness for the museum's preparation. At the time the earthquake hit, Avalos was preparing for the Oct. 24 opening of the Arabian display, and just beginning to devise a solution for shepherding in the largest and most unwieldy pieces he has encountered during his 23-year tenure at the museum.
The colossi also are outfitted with accelerometers — sensor equipment that will allow the museum and researchers at UC San Diego to understand how the pieces react to any kind of shaking, whether they be small vibrations or a full-fledged earthquake. Avalos said he hopes the information gathered can help other earthquake-prone museums better accommodate the traveling exhibition, and continue to innovate protection methods for some of San Francisco's greatest treasures.
“People ask, 'It's only here for three months. What are the odds?'” Avalos said. “Yes, it's only here for three months, but we have other exhibitions where this could work. And at some point, there is going to be an earthquake.”
“Roads of Arabia,” which also includes paleolithic tools dating back millions of years, 6,000-year-old gravestones, and other rarely seen treasures from Saudi Arabia, is on display at the museum until Jan. 18.