- Completion
- Jun 21, 202390% CONFIDENCEsource
Problem it solves
SourceSan Francisco's Millennium Tower was sinking and tilting because the soil under its north and west sides had compressed under the structure's weight.
How: A roughly $100 million fix drove 18 concrete piles into bedrock and shifted part of the building's load onto them, stopping the tilting; the rest of the building is expected to keep settling and stabilize over time.
San Francisco's Millennium Tower Fix Declared a Success
Construction research — October 24, 2026
June 21, 2023 reporting quotes the homeowners association that the foundation stabilization was substantially completed and its pile/load-transfer engineering project finished earlier that month. This supports Completed for the pinned retrofit success announcement, not the original tower build or a promise to reverse every inch of its lean. US$100 million is the retrofit cost; the announcement date remains distinct from later closeout.
- San Francisco’s infamous leaning tower has been fixed: A $100 million construction effort[3]
Earlier pin evidence
- A $100 million foundation upgrade of the Millennium Tower (301 Mission St., San Francisco) was substantially completed in June 2023, with 18 concrete piles driven to bedrock[2][3]
- Load transfer to the piles finished on 19 June 2023; survey data showed settlement 'has indeed been arrested' and the building 'has risen slightly', per engineer Ron Hamburger[2]
- The building tilted about 30 inches northwest over 15 years, and 7 inches of tilt occurred during the work[2]
- The fix is a scaled-down version of an original 52-pile plan whose initial pile driving caused extra settlement and a pause in 2021[2][3]
- Piles are socketed over 30 ft into rock 220 ft below grade; the HOA settled with the developer in 2020 and the tower stays under a 10-year monitoring plan[2][3]