Luxury tower in San Francisco is still sinking despite $100m to fix foundations

Millennium Tower has continued to move, sinking a full inch and leaning over as much as five inches at its top

A high-profile San Francisco development has already sunk $100 million extra dollars into shoring up its foundation as part of a lawsuit, but the building is still sinking.

In May, construction crews began digging massive, 100-foot deep holes lined with steel sleeves beneath the Millennium Tower in San Francisco’s financial district, hoping to install new supports anchored to subterranean bedrock to shore up the luxury residential development after years of it tilting sideways and sinking deeper into the ground.

However, since then, the building has continued to move, sinking a full inch and leaning over as much as five inches at its top, for a total of 22 inches of lean, according to NBC Bay Area, which monitored construction data.

“There has been no material harm to the building,” the building’s homeowners’ association told residents recently, “and it remains fully safe,” but would pause construction out of an “abundance of caution.”

Doug Elmets, a spokesman for the tower, said in a statement that the installation project, itself part of a legal settlement to a lawsuit from apartment owners in the building, would be paused for up to a month as engineers tried to learn more about the "increased settlement rate and available means of mitigating this.”

The 58-storey tower first opened in 2009, and its 419 luxury apartments were sold to a number of high-profile figures in the Bay Area, including former San Francisco 49ers quarterback Joe Montana, the late venture capitalist Tom Perkins, and San Francisco Giants outfielder Hunter Pence.

A decade later, the building had sunk an estimated 16 inches, and leaned 2 inches at its base and 6 at its peak, prompting a lawsuit from residents.

As part of a confidential settlement, it was agreed $100 million would be spent to instal 52 concrete piles, weighing a total of 140,000 pounds, to secure the project to a layer of bedrock 250 feet under the ground. Previously, the building’s foundation wasn’t attached to bedrock, but rather a 10-foot thick concrete mat supported with 950 piles nestled into soft soil and land fill earth.

David Williams, an Oakland-based structural engineering expert told NBC Bay Area the developments around the tower sinking were “disturbing” and that pausing construction is a “no-brainer” until experts identify the source of the problem.

“It’s very risky playing around with something that’s as complex as this structure’s foundation and not understanding what’s happening,” he added.