Shimmick Construction successfully completed the 36-in.-dia pilot pile casing installation at San Francisco’s Millennium Tower, proving the efficacy of the initial step of a less-disruptive construction method designed to allow the paused foundation fix to resume.
San Francisco Dept. of Building Inspection advises the Millennium Tower homeowners association to “refrain from resuming” the pile foundation retrofit for the settling 645-ft-tall condominium until a new approach to the fix is reviewed by the city.
Work on the nearly $100-million perimeter pile upgrade on the 645-ft-tall residential tower to prevent significant future settlement follows the resolution of litigation.
With the lengthy and complex permitting and approval process complete and almost all the other details worked out, construction could begin in mid-November on the estimated $100-million fix for San Francisco's 645-ft-tall Millennium Tower, which has settled more than 17 in. since its completion in 2009.
An independent engineering review team has given its nod to the San Francisco Dept. of Building Inspection regarding permitting of the proposed $100-million structural shoring scheme for the 645-ft-tall Millennium Tower—which has settled 17.3 in. over more than a decade.
Allana Buick & Bers, a forensic engineer hired by the Millennium Tower Association, says the cracked window glass in Unit 36B of the San Francisco residential building was caused by an exterior impact.
The 58-story Millennium Tower in the Transbay district of San Francisco, which has sunk 18 in. and is tilting 2 in., is under even more scrutiny for possible structural defects since a window on the 36th floor cracked.
Projects sited in areas with the worst soil—in high-risk seismic zones and subject to liquefaction—would require more than one geotechnical engineer on the peer-review team.
The city and county Dept. of Building Inspection issued interim guidelines and procedures for structural, geotechnical and seismic-hazard engineering design review for new buildings 240 ft or taller.