SF Millennium Tower Tilts Quarter Inch In Four Days

Newly released monitoring data shows that San Francisco's Millennium Tower tilted a quarter inch during the four days it took to install the first test pile to bedrock last month. From a local report: The monitoring data tracks settlement, tilting and water pressure levels underneath the sinking and leaning structure since work began on a fix for the troubled tower in May. Since work began to shore the sinking structure up on the north and west sides, the building has settled nearly 2 inches at the northwest corner and is now tilting more than two feet at that edge. The latest data -- including the four days that the test pile was installed from Nov. 15 to Nov. 19 -- shows a quarter inch of new tilt, as well as a tenth of an inch of settlement at the time the test installation occurred. At the same time, there was marked fluctuation of water pressure below the foundation on the Mission Street side of the structure.[...]Still, Ron Hamburger, the fix designer, recently assured city officials that the settlement that has occurred during testing of new methods designed to limit sinking is within expected levels. Hamburger now has city permission to install two more test piles. Hamburger told city officials the additional testing is needed to help determine just how many piles will ultimately be used to shore up the structure.

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