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
Multifamily Housing | Feb 24, 2016
Senior housing sector experiences record-setting year, says CBRE
Senior housing occupancy is at its highest level since 2007, and 2015 was a record year for sales and institutional transactions, according to CBRE.
Industry Research | Feb 22, 2016
8 of the most interesting trends from Gensler’s Design Forecast 2016
Technology is running wild in Gensler’s 2016 forecast, as things like virtual reality, "smart" buildings and products, and fully connected online and offline worlds are making their presence felt throughout many of the future's top trends.
Multifamily Housing | Feb 10, 2016
Miami review board recommends approval for Arquitectonica’s top-heavy condo tower
The 57-story Elysee Miami will offer residents impeccable views and plenty of amenities.
Multifamily Housing | Feb 5, 2016
Design guidelines for retail space in NYC affordable housing projects released
Aimed at designing efficient, flexible ground-floor space.
Multifamily Housing | Feb 2, 2016
10 top bathroom design trends for 2016
Floating vanities, tricked-out showers, and freestanding tubs highlight the top bathroom design trends, according to a survey of kitchen and bath design professionals by the National Kitchen and Bath Association.
Multifamily Housing | Feb 1, 2016
Top 10 kitchen design trends for 2016
Charging stations, built-in coffeemakers, and pet stations—these are among the top kitchen design trends for the coming year, according to a new survey of kitchen and bath designers by the National Kitchen & Bath Association.
Codes and Standards | Jan 22, 2016
Treasury Dept. will start crackdown on illicit money in luxury real estate
The move is expected to impact high-end condo development.
| Jan 14, 2016
How to succeed with EIFS: exterior insulation and finish systems
This AIA CES Discovery course discusses the six elements of an EIFS wall assembly; common EIFS failures and how to prevent them; and EIFS and sustainability.
Multifamily Housing | Jan 8, 2016
Manager of New York’s first micro-unit development inks pact with ‘personal butler’ service
The co-living platform Ollie is leasing its initial building, in New York, with housekeeping and grocery shopping available via Hello Alfred.
Urban Planning | Jan 4, 2016
The next boomtown? Construction and redevelopment sizzle in San Diego
The city's emission-reduction plan could drive influx into downtown
