San Francisco high-rise sinking, tilting

bigpicture7

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Some cool details on the proposed fix:

https://www.enr.com/articles/46053-review-of-proposed-fix-for-sinking-millennium-tower-could-take-several-months



They are planning to extend the tower's 10ft thick mat slab outboard, then literally pile jack the extended mat with bedrock-anchored piles:
Piles would extend up through an 8-ft-wide extension of the tower’s 10-ft-thick reinforced concrete mat—4 ft from the old mat. New and old mats would be connected by chipping into the side of the old mat and coupling new reinforcing steel onto existing rebar.
Fascinating:
The system relies on loading each pile with 800,000 lb using a permanent hydraulic jack that reacts against a new mat extension. The jacks would be housed in a maintenance access vault above the mat (see diagram, facing page). The team has applied for an easement to work under the sidewalks, which meet at the northwest corner of the block.
The quick math: 800k lb x 52 piles = 41.6 million lb of jacking force
(holy moly)
 

stick n move

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I cant get past the paywall but by jacking it is that just to anchor it to bedrock finally or will the jacks move it back the 4” it tilted?
 

chmeeee

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The plan is to allow the sinking side so that the other side will sink a bit to relevel it.
 

stick n move

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NYC now has its own leaning tower. I never remember this happening before, now theres multiple examples...

“The contractor on Fortis Property Group’s Lower Manhattan apartment building is suing the developer, claiming the shiny tower is leaning 3 inches north. Pizzarotti, the contractor on the project at 161 Maiden Lane, filed a lawsuit against Fortis in New York State Supreme Court, Commercial Observer reports. Pizzarotti has overseen construction since 2015, and claims poorly executed foundation work done before it joined the project is causing the problem.”



https://www.bisnow.com/new-york/news/construction-development/fortis-fidi-condo-building-is-leaning-contractor-claims-98352#ath
 

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