Since completing construction, the 58-story Millennium Tower has become San Francisco’s most infamous building.
The tower is founded on piles driven through soft, compressible clay soils deposited by San Francisco Bay and extending into a dense sand layer over ancient marine deposits of clays, silts, and sands, according to engineering firm Simpson Gumpertz & Heger (SGH). The building’s weight and nearby construction projects caused consolidation and lateral displacement of the soils, which led to the tower settling more than 17 inches and tilting four inches across its footprint. Needless to say, this tilting began to worry residents and thrust the building into the national spotlight.
After a two-year permitting and approval process, a fix is finally set to move forward with SGH as the engineer-of-record. SGH evaluated whether the building required structural reinforcement to restore its integrity or seismic resistance to original levels. SGH lists the outcomes of the evaluation as:
– Developed detailed nonlinear models of the structure, its foundations, and underlying soil to simulate the effects of settlement and tilting
– Conducted detailed nonlinear analyses of the structure’s response to earthquake shaking
– Designed an underpinning retrofit for the structure, consisting of jacking approximately 20% of the building’s weight onto new foundation piles (52 piles to be exact) extended to rock along the structure’s north and west sides
The fix will prevent any future settlement and reverse the current tilting over time. The project is expected to begin this fall.
Related Stories
Projects | Mar 2, 2022
Manufacturing plant gets second life as a mixed-use development
Wire Park, a mixed-use development being built near Athens, Ga., will feature 130 residential units plus 225,000 square feet of commercial, office, and retail space. About an hour east of downtown Atlanta, the 66-acre development also will boast expansive public greenspace.
Multifamily Housing | Feb 25, 2022
First set of multifamily properties achieve BREEAM certification in the U.S.
WashREIT says it has achieved certification on eight multifamily assets under BREEAM’s In-Use certification standard.
Multifamily Housing | Feb 24, 2022
First new, mixed-use high-rise in Detroit’s central business district in nearly 30 years opens
City Club Apartments completed two multifamily projects in 2021 in downtown Detroit including the first new, mixed-use high-rise in Detroit’s central business district in nearly 30 years.
Codes and Standards | Feb 21, 2022
More bad news on sea level rise for U.S. coastal areas
A new government report predicts sea levels in the U.S. of 10 to 12 inches higher by 2050, with some major cities on the East and Gulf coasts experiencing damaging floods even on sunny days.
Urban Planning | Feb 14, 2022
5 steps to remake suburbs into green communities where people want to live, work, and play
Stantec's John Bachmann offers proven tactic for retrofitting communities for success in the post-COVID era.
Senior Living Design | Feb 11, 2022
Design for senior living: A chat with Rocky Berg, AIA
Rob Cassidy, Editor of MULTIFAMILY Design + Construction, chats with Rocky Berg, AIA, Principal with Dallas architecture firm three, about how to design senior living communities to meet the needs of the owner, seniors, their families, and staff.
Multifamily Housing | Feb 8, 2022
Suffolk to build Alba Palm Beach
The project will feature 55 residences.
| Feb 4, 2022
New apartment complex Dixon Place honors the history of Salt Lake City
Salt Lake City’s Sugar House neighborhood has been experiencing somewhat of a renaissance as of late, and the opening of new apartment community Dixon Place continues that trend. MVE + Partners took leadership in the design of the 59-unit, Class A development.
Sponsored | Steel Buildings | Jan 25, 2022
Multifamily + Hospitality: Benefits of building in long-span composite floor systems
Long-span composite floor systems provide unique advantages in the construction of multi-family and hospitality facilities. This introductory course explains what composite deck is, how it works, what typical composite deck profiles look like and provides guidelines for using composite floor systems. This is a nano unit course.
Multifamily Housing | Jan 20, 2022
Texas’ first cohousing residential community breaks ground in East End Houston
The design will include sustainability elements.
