By Deborah Goonan, Independent American Communities
San Francisco’s Millennium Tower has gained notoriety for sinking 18-inches into the soil beneath the mammoth structure, causing the building to tilt to one side.
For several years, condo owners and the homeowners association have been engaged in legal battles with the developer. Both sides conducted various invasive tests of the site and the building, and the City’s Department of Building Inspection (DBI) was supposed to be kept in the loop by Millennium’s mangement team.
But after a window cracked on the 36th floor of the tower over Labor Day weekend, DBI found out about the problem from local media reports (see video about the drone accident, below), not from the HOA or its manager.
Earlier this week, that communication breakdown prompted DBI to threaten to “yellow-tag” the building if certain safety measures and inspections were not completed by Friday, September 14. DBI later backed off of its threat, allowing Millennium Tower’s management team a bit more time to arrange for DBI inspections of some 400 units in the building, as well as repair of its window washing crane.
The cracked window has been taped from the inside, and the HOA says its engineers have not yet determined the cause of the cracking. The HOA has begun the process of erecting scaffolding around the tower, in order to protect pedestrians, vehicles, and neighboring buildings from potential damage due to falling debris.
Earlier this week, the HOA hired a drone operator to attempt to get photographs of the exterior of the window, to help determine the cause of the cracking. But, as bad luck would have it, the drone lost its satellite signal and came crashing down to the ground, nearly hitting a young boy.
Amidst all of this chaos, NBC Bay Area reports that there may be a solution in the works. The proposed $80 million fix would be far less expensive than the $400-$500 million proposal to drive dozens of piles through the building’s foundation and down 200 feet into bedrock.
Instead, the developer is reportedly proposing to drive fewer but larger piles into the sidewalks along the northwest corner of the building, then attach these supports to the building’s foundation.
However, an engineer interviewed by NBC Bay Area, Joe Maffei, expresses some skepticism about this cheaper solution. What if driving piles on one side of the tower allows the building to continue sinking on the other side, causing it to tilt in the opposite direction?
The video in the following report illustrates the developer’s proposed solution.
But anyone following this story is apt to wonder if cheaping out on an after-the-fact foundation support system is a good idea, especially since Millennium Tower’s sinking and leaning appears to have been caused by cutting corners on the original foundation’s support system.
A New, Less Expensive Proposal to Shore Up Tilting Millennium Tower Being Considered
By Jaxon Van Derbeken
Published at 8:34 PM PDT on Sep 11, 2018 | Updated at 11:35 PM PDT on Sep 11, 2018
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.
Read more (video):
https://www.nbcbayarea.com/news/local/A-New-Less-Expensive-Proposal-to-Shore-Up-Tilting-Millennium-Tower-Being-Considered-493014881.html
Additional references:
At Millennium Tower, that window isn’t the only thing that’s broken
Matier & Ross Sep. 12, 2018 Updated: Sep. 12, 2018 6 a.m. (San Francisco Chronicle)
City threatens to yellow tag Millennium Tower
Homeowners must fix problems related to cracked window ASAP
By Adam Brinklow Sep 13, 2018, 8:51am PDT (Curbed San Francisco)
Safety measures ordered at sinking Millennium Tower (Fox 2 KTVU)
POSTED: SEP 13 2018 05:06PM PDT
VIDEO POSTED: SEP 26 2016 05:46PM PDT
UPDATED: SEP 13 2018 08:40PM PDT
City threatens to yellow-tag SF’s sinking Millennium Tower if demands not met
Dominic Fracassa Sep. 12, 2018 Updated: Sep. 12, 2018 9:02 p.m.(San Francisco Chronicle)
SF backs off threat to yellow-tag Millennium Tower
By Dominic Fracassa Updated 9:12 pm PDT, Thursday, September 13, 2018 (SF Gate)