Leaning Millennium Tower Finally Fixed? Structural Retrofit Finished, Tower Tilting Slightly Less

Jun 26, 2023

The $100 million fix to the notoriously sinking and tilting Millennium Tower is completed, and early results show the encouraging development that it’s already reversed its tilt by, well, an inch.

We’ve had many a good laugh at the Millennium Tower, initially considered one of the world’s premier luxury condos, but was discovered to be leaning and tilting in 2016 — a story that made international headlines. There were immediate lawsuits from jilted-feeling condo owners (including Joe Montana), and the price of those condos briefly plummeted but has since recovered.

It became even funnier when the luxury units stank to high heaven because of alleged conduction shortcuts, though it was also a little terrifying that the 645-foot building could have caused a massive public safety disaster.

The area around the tower at Mission and Fremont streets has been getting dug up for years now. A $100 million fix was initiated in 2020, but discouragingly, the fix only made the tower lean more. So a revised fix was approved last August. And now the San Francisco Business Times reports the Millennium Tower retrofit has been completed, with encouraging early results.

NEW: A years-long retrofit effort to stop #SanFrancisco's Millennium Tower from tilting and sinking is now in its final stages and has been deemed successful in counteracting the 400+ unit condo tower's issues. Story here👇https://t.co/cpGKz4W80N

"The size of the building, the amount of load we were transferring — it's really the first time that something of this magnitude has been done," the project’s lead engineer Ron Hamburger told the Business Times. "The basic approach, which is called the underpinning, has been done many times, but at much smaller scales. So we really had to invent some things to basically let us deal with the difference in scale of this project."

How big was the scale of this project? As the Chronicle explains, 18 concrete piles were installed 275 feet below ground-level, with each pile able to support the weight of a million pounds. So that shifts 18 million pounds off the structure’s foundation.

The tower will still be monitored for the next decade to make sure the tilting is fully reversed. But the SF Business Times says that accordion to the Millennium Tower's Homeowner's Association, the foundation has “showed recovery of nearly one inch of tilt.”

That association’s president Howard Dickstein said in a statement to the Chronicle that the “engineering upgrade will restore our building’s reputation and the value of condominiums while putting to rest any lingering questions about the Tower’s stability.”

But about that “reputation.” The building’s reputation is that of a few fixes not having worked, so it’s surely too early to declare this project did the trick. And experts all agree that these are uncharted waters, in terms of a very heavy, tall building sitting on soil that hasn't been tested in this way before.

“They have claimed early success before – that was premature,” independent deep foundations expert David Williams tells NBC Bay Area. “So right now, we’ll have to wait and see how it responds.”

The overall work on the project is not yet complete. According to the Chronicle, some new sidewalk concrete will be poured, some Muni lines will be restored, and new trees will be planted, with an expected completion timeframe of August.

Related: Millennium Tower May Be Sinking Faster Due to Digging That's Part of Effort to Stop It Sinking [SFist]

Image: A picture of the Downtown San Francisco skyscrapers when looking up, including the 181 Fremont, the Salesforce Tower and the Millennium Tower buildings. (Getty Images)