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UPDATE: Despite Warnings, Repairs on San Francisco's Millennium Tower Caused Additional Sinking

By Abigail Sterling and Max Darrow

SAN FRANCISCO (KPIX 5) -- Construction on a fix for San Francisco's leaning Millennium Tower came to a stop in late August because the fix was actually making the tower sink even more. Now it appears some of that damage could have been avoided.

The construction is partially back on track with some test drilling underway this week. Engineers have a plan to drill just two casings with a modified technique that they say will cause less vibration.

ALSO READ: Warnings About San Francisco Millennium Tower Repair Plans Raised Before Work Began

"Millennium Partners wanted to get the thing wrapped up," said Robert Pyke, a geotechnical engineer and early critic of the current so-called "perimeter pile upgrade." He says the $100 million plan to shore up the sinking tower should have been stopped months before it was.

"Certainly by the end of June it was obvious that there was additional settlement as a result of installing the casings and the piles," said Pyke.

KPIX asked him to review engineer logs and internal emails obtained by KPIX 5. A chart produced by the team shows the accelerated sinking started in mid-May but work on the project continued through June and July.

ALSO READ: Planned Fix To San Francisco's Leaning Millennium Tower Getting New Scrutiny From City Hall

In an email on July 29, the Engineering Design Review Team (EDRT) hired by the city to oversee the project warned building officials: "The design team has suggested to the 301 Mission Homeowners Association that the installation of 36-inch diameter casings along Mission street be paused," but … "this suggestion has not been acted on and the project is continuing to move forward."

On August 4, lead engineer Ron Hamburger finally confirmed "the project has placed a voluntary moratorium" on installation of 36-inch casings.

But drilling continued to install smaller 24-inch piles until August 23, when the Millennium Tower's general manager announced a pause in all construction for two to four weeks.

"I credit the EDRT with applying the necessary pressure, but they should not have had to do that. Any responsible engineer should have called a halt, as I said by the end of June," said Pyke.

Pyke believes the fact that construction continued for two months caused more damage.

"Another half to three-quarters of an inch of settlement," said Pyke.

He says the continued drilling may have even exacerbated a sewage problem at the luxury high-rise, described in an August 26th email as "third-floor kitchens experiencing some plugging."

"Even a small change in gradient might upset the plumbing, both wastewater and sewage," said Pyke.

In a statement to KPIX, lead engineer Ron Hamburger admitted some of the sinking and tilting could have been avoided by halting construction earlier. In a letter to building officials, he also admitted the new test drilling that started this week could cause even more sinking. However, he insists none of this will affect the building's safety.

But one thing is for sure: all the problems at 301 Mission Street seem to be having an impact on property values. We found ten 10 condos listed for sale, all at discount prices. Zillow estimates one luxury condo listed for $1.75 million was worth about $1 million more just five years ago.

Some units have been on the market for months. Unit 14H, for a bargain of $899,000, has been for sale for nearly a year.

Pyke believes concern over property values might be one reason why the Millennium Tower Association pushed to continue the job.

"That would suit the existing homeowners and the homeowners association because once it was completed and construction finished there's no question that the property values will go back up," said Pyke.

The Millennium Tower Association that represents homeowners is still not commenting. Interestingly though, we found an online presentation that Hamburger did in February for students at the University of Minnesota that seems to confirm property values are at the core of all this. In it Hamburger points out "There is no reason structurally that the building needs to be upgraded. Homeowners needed a major retrofit to 'revalue' their units."

No real estate expert was willing to go on the record for this story. But one of them did access current data for us that shows 13 listings in the building either expired or were taken off the market since January.

Ron Hamburger full statement to KPIX 5:

"While some of the settlement and tilting that has occurred in recent months could have been avoided by halting construction earlier, neither the building's safety or functionality have been affected and the project team gathered valuable information on the causes of this settlement as construction progressed. This places us in a better position to mitigate these effects as we move forward to complete the project. On the day that I recommended that the 36 inch pile installation stop, the Millennium Tower HOA instructed the contractor to stop, in line with my recommendation."

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