San Francisco

A New, Less Expensive Proposal to Shore Up Tilting Millennium Tower Being Considered

A new fix for the tilting and sinking Millennium Tower is on the table at closed door talks this week, NBC Bay Area has learned. The goal is to find a solution that will settle the massive legal fight, and stabilize the troubled building.

The $80 million proposal can’t come soon enough for residents of the troubled building. Nerves are already on edge following the cracking of a 36th floor window over Labor Day weekend.

“I think the homeowners are waiting, and anxious,” said attorney and engineer Jerry Dodson, who lives on the tower’s 42nd floor. “These kind of problems that crop up with the building make that more of an alarming situation that needs to be dealt with.”

The idea behind the latest plan is to create a way to stop the building from tilting more, but not straighten it back out. The tower is currently tilting by 18 inches.

The question is whether the fix is sufficient. One expert told NBC Bay Area the current 18-inch leaning may already be putting the tower’s seismic performance at risk.

“It’s getting to a point where it conceivably could have an impact,” said Joe Maffei, a San Francisco structural engineer who specializes in seismic performance of high rise buildings.

The newly proposed $80 million fix is far cheaper than an earlier concept touted by the Millennium Tower Homeowners Association. That approach – currently estimated to cost between $400 million and $500 million – would rely on inserting 150 piles after drilling through the building’s 10 foot thick concrete foundation slab.

The less expensive alternative, proposed by structural engineer Ron Hamburger on behalf of the tower’s developer, relies on fewer, larger piles sunk on the outside of the existing foundation and then connected to the foundation.

There would a total of 52 piles, each capable of handling 1 million pounds. There would be 26 set on either side of the building’s northwest corner at Fremont and Mission streets. That’s where the sinking and tilting is most pronounced.

The plan is cheaper in part because using the sidewalk will allow quick and easy access for heavy equipment needed to put piles into the ground.

“That seems to make more sense to me; you will be installing the piles in the city owned property,” Maffei said. However, he also noted that shoring just one side of the tower has its risks.

“You can ask the question,” he said, “Well, that’s hopefully going to stop that side … but what if the other side continues sinking and it starts tilting the other direction?”

One option that has been tried in Mexico City is to make the new system adjustable to offset any new shifting forces, Maffei said.

“I think there’s a little bit of a balancing act with this,” he added.

The Millennium Tower’s developer isn’t talking about the latest proposed fix, which is being considered during days of closed door talks this week. But in a recent decision, the judge overseeing the massive legal case involving the tower indicated there was encouraging news on a fix.

Sources told NBC Bay Area the Millennium may even offer some sort of guarantee, and that would be good news for owners who have been stuck waiting for progress.

“We need to get on with it,” a frustrated Dodson said.

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