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
| Feb 8, 2012
Nauset completes addition and renovation for Winchester senior living community
Theater, library, fitness center, and bistro enhance facility.
| Jan 3, 2012
Rental Renaissance, The Rebirth of the Apartment Market
Across much of the U.S., apartment rents are rising, vacancy rates are falling. In just about every major urban area, new multifamily rental projects and major renovations are coming online. It may be too soon to pronounce the rental market fully recovered, but the trend is promising.
| Dec 27, 2011
Ground broken for adaptive reuse project
Located on the Garden State Parkway, the master-planned project initially includes the conversion of a 114-year-old, 365,000-square-foot, six-story warehouse building into 361 loft-style apartments, and the creation of a three-level parking facility.
| Dec 12, 2011
Mojo Stumer takes top honors at AIA Long Island Design Awards
Firm's TriBeCa Loft wins "Archi" for interior design.
| Dec 5, 2011
Gables Residential brings mixed-use building to Houston's Tanglewood area
The design integrates a detailed brick and masonry facade, acknowledging the soft pastel color palette of the surrounding Mediterranean heritage of Tanglewood.
| Dec 2, 2011
What are you waiting for? BD+C's 2012 40 Under 40 nominations are due Friday, Jan. 20
Nominate a colleague, peer, or even yourself. Applications available here.
| Dec 2, 2011
Goody Clancy awarded Ohio State residential project
The project, which is focused on developing a vibrant on-campus community of learning for OSU undergraduates.
| Nov 29, 2011
Suffolk Construction breaks ground on Boston residential tower
Millennium Place III is a $220 million, 256-unit development that will occupy a full city block in Boston’s Downtown Crossing.
| Nov 15, 2011
Suffolk Construction breaks ground on the Victor housing development in Boston
Project team to manage construction of $92 million, 377,000 square-foot residential tower.
| Nov 15, 2011
Miller joins Perkins Eastman as regional manager, Middle East and Northern Africa
Miller joins Perkins Eastman with more than 48 years of experience in architecture, design management, and construction administration for planning and infrastructure.
