San Francisco’s Millennium Tower fix approved, moving forward

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.

The Tampa Bay Rays Major League Baseball team announced that it has reached an agreement with St. Petersburg and Pinellas County on a $6.5 billion, 86-acre mixed-use development that will include a new 30,000-seat ballpark and an array of office, housing, hotel, retail, and restaurant space totaling 8 million sf.

Engineers | Sep 15, 2023

NIST investigation of Champlain Towers South collapse indicates no sinkhole

Investigators from the National Institute of Standards and Technology (NIST) say they have found no evidence of underground voids on the site of the Champlain Towers South collapse, according to a new NIST report. The team of investigators have studied the site’s subsurface conditions to determine if sinkholes or excessive settling of the pile foundations might have caused the collapse.

MFPRO+ Research | Sep 11, 2023

Conversions of multifamily dwellings to ‘mansions’ leading to dwindling affordable stock

Small multifamily homes have historically provided inexpensive housing for renters and buyers, but developers have converted many of them in recent decades into larger, single-family units. This has worsened the affordable housing crisis, say researchers.

Deciphering the Differences in Smart Lock Networks

Adaptive Reuse | Aug 31, 2023

New York City creates team to accelerate office-to-residential conversions

New York City has a new Office Conversion Accelerator Team that provides a single point of contact within city government to help speed adaptive reuse projects. Projects that create 50 or more housing units from office buildings are eligible for this new program.