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
MFPRO+ News | Nov 1, 2023
Washington, D.C., Queens, N.Y., lead nation in number of new apartments by zip code
A study of new apartment construction by zip code showed Washington D.C., and the Queens borough of New York City are the hottest multifamily markets since 2018, according to RentCafe.
Adaptive Reuse | Nov 1, 2023
Biden Administration reveals plan to spur more office-to-residential conversions
The Biden Administration recently announced plans to encourage more office buildings to be converted to residential use. The plan includes using federal money to lend to developers for conversion projects and selling government property that is suitable for conversions.
Sponsored | MFPRO+ Course | Oct 30, 2023
For the Multifamily Sector, Product Innovations Boost Design and Construction Success
This course covers emerging trends in exterior design and products/systems selection in the low- and mid-rise market-rate and luxury multifamily rental market. Topics include facade design, cladding material trends, fenestration trends/innovations, indoor/outdoor connection, and rooftop spaces.
MFPRO+ Special Reports | Oct 27, 2023
Download the 2023 Multifamily Annual Report
Welcome to Building Design+Construction and Multifamily Pro+’s first Multifamily Annual Report. This 76-page special report is our first-ever “state of the state” update on the $110 billion multifamily housing construction sector.
Mass Timber | Oct 27, 2023
Five winners selected for $2 million Mass Timber Competition
Five winners were selected to share a $2 million prize in the 2023 Mass Timber Competition: Building to Net-Zero Carbon. The competition was co-sponsored by the Softwood Lumber Board and USDA Forest Service (USDA) with the intent “to demonstrate mass timber’s applications in architectural design and highlight its significant role in reducing the carbon footprint of the built environment.”
Sponsored | MFPRO+ Blog | Oct 26, 2023
Unlock New Potential—Can Multifamily Pop-Up Hotel Concepts Transform Lease-Ups?
Dive into the new trend of multifamily pop-up hotels! Learn how they're changing the game in lease-ups, creating vibrant communities, and offering property managers a lucrative new revenue stream. Join the conversation on the future of multifamily living spaces.
Giants 400 | Oct 23, 2023
Top 115 Multifamily Construction Firms for 2023
Clark Group, Suffolk Construction, Summit Contracting Group, Whiting-Turner Contracting, and McShane Companies top the ranking of the nation's largest multifamily housing sector contractors and construction management (CM) firms for 2023, as reported in Building Design+Construction's 2023 Giants 400 Report. Note: This ranking factors revenue for all multifamily buildings work, including apartments, condominiums, student housing facilities, and senior living facilities.
Giants 400 | Oct 23, 2023
Top 75 Multifamily Engineering Firms for 2023
Kimley-Horn, WSP, Tetra Tech, Olsson, and Langan head the ranking of the nation's largest multifamily housing sector engineering and engineering/architecture (EA) firms for 2023, as reported in Building Design+Construction's 2023 Giants 400 Report. Note: This ranking factors revenue for all multifamily buildings work, including apartments, condominiums, student housing facilities, and senior living facilities.
Giants 400 | Oct 23, 2023
Top 190 Multifamily Architecture Firms for 2023
Humphreys and Partners, Gensler, Solomon Cordwell Buenz, Niles Bolton Associates, and AO top the ranking of the nation's largest multifamily housing sector architecture and architecture/engineering (AE) firms for 2023, as reported in Building Design+Construction's 2023 Giants 400 Report. Note: This ranking factors revenue for all multifamily buildings work, including apartments, condominiums, student housing facilities, and senior living facilities.
Senior Living Design | Oct 19, 2023
Senior living construction poised for steady recovery
Senior housing demand, as measured by the change in occupied units, continued to outpace new supply in the third quarter, according to NIC MAP Vision. It was the ninth consecutive quarter of growth with a net absorption gain. On the supply side, construction starts continued to be limited compared with pre-pandemic levels.
