“There's no question that the fix has made things worse,” said Bob Pyke, a veteran geotechnical engineer who has advised Caltrans and federal agencies on large construction projects. Raj Mathai speaks with Jaxon Van Derbeken on this.īut critics of the fix are taking a wait and see attitude, saying the latest problem was totally predictable. They say that gave them confidence they could tie the building to bedrock at the corner without making the tilting worse.Ī nearly forgotten underground wall could prove a serious obstacle to reversing the tilt of the Millennium Tower, a major goal of the $100 million fix for the troubled San Francisco high rise. When work was shifted to the corner of Fremont to Mission in June, fix authorities said, they did not see more tilting during the digging there. “This will stabilize the structure and help us to complete the work on Fremont street without additional tilting,” Millennium fix officials said in the statement, while stressing the additional tilting this year never endangered building safety. Rather than try to shore up the Mission and Fremont street sides of the foundation simultaneously, they are going to partially anchor just the northwest corner to piles already installed last year, essentially propping it up near the corner. To prevent more tilting while construction continues, fix engineers will change the sequencing of the project. In a statement, the Millennium Tower Homeowners Association said they responded as soon as monitoring data showed “increased building tilt to the west.” That’s when they opted to halt the half-completed work along Fremont on May 26, to give them time to devise an alternative. Hamburger promised that if the building tilted more than three inches to the west, he would reevaluate the strategy. SF's Millennium Tower Settles Another One-Tenth of an Inch During 1 Week of Digging Monitoring data showed the tower had listed another 2.75 inches west, toward Fremont Street, in just the first half of the year – and the building’s tilting hastened in May when digging began for the underground wall on Fremont Street.įix engineer Ron Hamburger had predicted the tower would tilt an additional three inches westward for the entire year. While the city has yet to sign off on that scaled back plan, new problems emerged when engineers began the digging needed to construct underground shoring walls to allow the foundation to be extended. To stem the damage, engineers opted to cut the number of new foundation support piles from 52 to 18. But since work began on installing support piles in May of last year, the problems have gotten worse, not better. The $100 million retrofit project – partially paid for by taxpayers as part of a resolution of litigation – was supposed to keep the building from sinking and tilting more and stabilize property values. NBC Bay Area’s Investigative Unit has learned that a recent acceleration in tilting of the Millennium Tower has prompted engineers in charge of the so-called "fix” to employ an unconventional strategy to prop up the building so as to stop it from leaning further while the rest of the work gets done.
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