[Pedestrian]

Test Drilling Launched at the Sinking Millennium Tower
By Jaxon Van Derbeken
Published at 10:53 PM PST on Jan 31, 2018 | Updated at 11:46 PM PST on Jan 31, 2018

Crews have quietly launched a $9 million exploratory drilling project at the Millennium Tower to evaluate a planned fix for the sinking and tilting structure, NBC Bay Area has learned.

The project started earlier this month on Beale Street and involves drilling holes between 200 and 300 feet down to bedrock. The goal is to see whether the method will stabilize the troubled foundation.

The building has sunk some 17 inches and is leaning to the north and west. The project to shore up that foundation could cost $150 million.

If test results are promising and the plan passes muster, engineers would bore some 100 to 150 holes through the tower’s 10-foot-thick, steel-reinforced concrete foundation.

The so-called micropile strategy is not new; it was used to shore up the Mandalay Bay Resort in Las Vegas, which sank some 18 inches during construction before being stabilized by more than 500 micropiles . . . .

https://www.nbcbayarea.com/investiga...472069803.html