Millennium Tower is tilting, sinking more than expected

More disheartening news for the troubled Millennium Tower, Yerba Buena’s tony high-rise that’s tilting and sinking into the earth. A week ago, the Chronicle’s Matier and Ross broke news that the sleek structure was sinking upward of 16 inches and tilting every-so-slightly northeast of the in-progress Transbay Center. Now the two are back to tell us that things are getting worse.

It turns out that neither the sinking nor the tilting are slowing down.

A geotechnical engineer hired by the 58-story condo tower’s homeowners association — and paid for by the developer — warned residents in May that the building is still sinking at a rate of about an inch a year and shows no signs of slowing down, according to those in attendance.

Patrick Shires, owner of a Los Gatos engineering company and a 40-year veteran in the field, said that over time the tower "most likely" will sink an additional 8 to 15 inches into the landfill beneath it at 301 Mission St. unless steps are taken to stop it. That means the worst-case scenario would have the South of Market landmark descending a total of 31 inches.

The building’s 2-inch tilt to the northwest at its base could get worse as well, Shires told the condo owners — some of whom are already taking legal steps to make someone pay for what they fear will be sinking home values.

As expected, residents are not pleased. While there have been no reports of visible damage to units, "cracks and some water intrusion have appeared in the underground garage." And on the sidewalks outside, there has reportedly been some "cracking and buckling."

Photo by Patricia Chang / Curbed SF

The problem, it would stand to reason, is that the Millennium Partners chose to build the luxe tower into the dense sand in lieu of the bedrock beneath. This could be one reason why the structure is sinking.

For their part, Millennium Partners have placed blame on the Transbay Joint Powers Authority’s nearby construction. And the TJPA has denied any and all responsibility. They even threw down $58 million on an underground buttressing system to support the troubled tower before commencing with construction.

Photo by Patricia Chang / Curbed SF

In related news, District Three supervisor Aaron Peskin, according to Hoodline, "is expected to introduce legislation that aims to protect the city from footing the cost of any bailouts."

Stay tuned.

• How low will it go? Millennium Tower’s troubles haven’t peaked [SF Chronicle]
• Millennium Tower May Be Sinking, Tilting Even More Than Expected [Hoodline]
• Transbay Center denies responsibility for Millennium Tower sinkage [Curbed SF]
• Millennium Tower: We were never ‘expected, advised, or required’ to drill into bedrock [Curbed SF]
• Millennium Tower sinking: Everything you need to know [Curbed SF]