How Buena Vista survived the quake

In the early morning of Aug. 24, seconds after the 6.0 earthquake shook Napa into flames and rubble, winery owner Jean-Charles Boisset sat up in bed, clutched his wife Gina Gallo and their twin daughters, confirmed they were all safe, and then, he later said, “The first thing I thought about was Buena Vista.”

Boisset, whose holdings include four wineries in Sonoma and Napa counties and a portfolio of family wineries in France, was not worried about the bottles and barrels of sparkling wine, prized chardonnay, pinot noir and zinfandel stored in the historic winery at the top of Old Winery Road just outside Sonoma.

He was worried about the three-story stone edifice, the Cellar Building, into which he had poured a large fortune, and a vibrant, Franco-American vision, to restore the single most important structure in American wine history, and to resurrect the story and the heritage imbedded in the building.

Anyone in possession of a 157-year-old stone building still standing near the intersection of some of the livelier fault lines in California would have reason to worry.

Boisset pulled on some pants over his signature red monogrammed socks and raced to Sonoma from his Napa Valley home. So did Tom Blackwood, Buena Vista’s director of retail operations who lives on the west side of Napa, as did Naomi Miroglio, the historical architect who helped breathe new life into what was almost a stone corpse.

“I was really, really worried about what we would find,” Boisset said this week, standing outside the stone edifice. “But the only thing that fell over was a wire bird cage.”

That was because, said Blackwood, the stately stone building was renovated from the inside out with modern technology that “let it move a little. It did what it was supposed to do, and it worked.”

The technology used at Buena Vista is called center core drilling, and instead of running bolts perpendicular through the walls of unstable buildings, like an internal cage, the new system drills vertically through the walls, reaming out holes four to six inches in diameter, into which are inserted reinforced steel rods that are connected to eye bolts in the floor. A special resin is then forced down the holes and into adjoining cracks and crevices, creating a solid bond.

At one point, as workmen were drilling vertical holes through the east wall of the structure, they discovered the original mortar had largely turned to dust. They were afraid, said Blackwood, that “if anything happened while they were up on that wall, the whole thing would come down and they’d have been killed.”

For that reason, said Eric Kreager, a structural engineer whose Santa Rosa firm MKM & Associates worked on the renovation, “They had to be really careful how they did that, alternating the holes from side to side.”

Kreager said center core drilling is somewhat more expensive than the traditional method of installing brace frames, “but the outcome is much nicer. And you’re not only reinforcing the wall with the rods, but you’re pushing the epoxy into all the cracks. The building then has a little bit more flexibility, which can be a benefit.”

In a formal evaluation made soon after the quake, Kreager wrote, “The Cellar Building had no perceivable signs that (the ground movement) had any real effect on the building and no significant structural damage was noted on the exterior walls. The interior retrofit connections of the stone wall to the structure also have no signs of distress.Other than a few museum pieces on the uppermost floor that were thrown across the room, the structure was completely intact.The structural retrofit provided the performance and safety required to keep the building open for use following the earthquake.”

A similar evaluation by historical restoration architect Miroglio reached the same conclusion. “We are extremely pleased with how well the Cellar Building performed in the recent earthquake. Thankfully, due to the foresight and stewardship demonstrated by Jean-Charles Boisset, the ingenuity of MKM Structural Engineers, and the craftsmanship of (contractors) Cello & Madru, necessary steps were taken two years ago to seismically reinforce this significant historic resource.The technically advanced seismic reinforcement system performed as designed, saving this historic treasure for future generations.”

Blackwood had his own, informal and non-technical assessment when he asserted this week, without the retrofit, “At least the east wall would have failed. And if the east wall would have fallen down, it would have been the end for this building. It would have been difficult to rebuild.”

For his part, Boisset, ever intent on preserving and promoting the unique history of the winery he has resurrected, sees the earthquake as an affirmation of his vision. He calls the structure “the White House of the wine world of America,” and ascribes its survival to “the incredible leadership of all involved, Naomi the architect, the unbelievable engineering team – for the renovation not to be seen, but to still resist all the vibrations and not break, it’s amazing. It protects America’s historical legacy and preserves that heritage for our children.”

Waxing onward, he added, “We are all shareholders of the past. If you touch history, you have to get close to it.”

Blackwood admitted this week that he has now been uncomfortably close to history twice. The first time was during the Loma Prieta earthquake in 1989, when he was aboard an AC Transit bus on the Bay Bridge when the quake struck and the bus came within 10 feet of the collapsed deck portion.

The second time was Aug. 24 when, he said, “I was more scared in west Napa than I was on the Bay Bridge.”