On the heels of its tenth anniversary, downtown San Francisco’s controversial Millennium Tower may soon turn things around. After it was announced in 2016 that the 645-foot-tall tower had sunk 17 inches into the ground and tilted 18 inches west, the city threatened to block access to the building until a swift and cost-efficient solution was found. Last year, the city announced a $100 million solution to retroactively construct proper bedrock-supported piles to stabilize the residential tower. According to the San Francisco Chronicle, that plan was endorsed late last month by a four-person panel hired by the city, after deliberating that they “[saw] no reason to withhold approval of the building permit." The structural engineering firm Simpson Gumpertz & Heger proposed that the building’s original structural system, a “10-foot-thick concrete foundation bonded by nearly 1000 reinforced concrete piles driven close to 90 feet into a layer of soft clay,” could safely be replaced by a set of piles long enough to reach the bedrock underneath. At 250 feet tall, two feet wide, and over 140,000 pounds each, the 52 new steel-and-concrete piles will provide significantly more structural stability than their predecessors. Simpson Gumptertz & Heger concluded that the improvements will not come quickly; it's estimated that each pile will take "three to four days to drill into place,” and the process would be made more difficult with the addition of a “reinforced concrete inner pile installed within each steel shaft.” However, when considering the city’s history of catastrophic earthquakes, the revised structural plan will no doubt serve to put its residents and neighbors at ease. The San Francisco Department of Building Inspection warned that if plans were not made to improve the structural conditions of Millennium Tower, the building could sink and tilt at an exponential rate, while adding that it could “increase forces and deformations on the foundation, which may in the future trigger mandatory repair provisions of the San Francisco existing building code.” The solution will likely set a precedent for other towers being built in the area and elsewhere. Niall McCarthy, an attorney representing a group of homeowners, told the Guardian that “this litigation exposed a lot of problems in the development of this particular building,” and that “it will be a roadmap for other downtown developments for what to avoid.” Though its original structural system—dropping piles into soft, loamy soil instead of attaching it to bedrock—is fairly common in the city, it should have been anticipated that Millennium Tower’s significant weight and height would have necessitated more substantial footing.
Posts tagged with "Millenium Tower":
The City of San Francisco is filing a lawsuit against the developer of the 58-story Millennium Tower, which has sunk 16 inches since completion, causing it to tilt, among other issues. San Francisco’s city attorney Dennis Herrera said that he was filing the lawsuit on the grounds that Mission Street Development failed to notify the buyers and the city that the building was sinking at this rate. Since the building was completed in 2008, Mission Street Development has made hundreds of millions of dollars in sales from the approximately 400 units in the building, according to The New York Times. Apartments in the tower cost millions to purchase and the current owners of these apartments are understandably furious. Questions have been raised about the building’s abilities to withstand an earthquake and what ramifications this could have on not only those who live within the building, but for the buildings surrounding it. Its foundation piles are 90-feet short (rather than the 225-foot piles that would have reached bedrock). The skyscraper currently under construction next to the Millennium Tower, for example, has a foundation that reaches down to bedrock. P.J. Johnston, a spokesperson for Mission Street Development, told The New York Times that the city’s construction on the nearby Transbay Terminal caused the unexpected sinking when it removed water from the ground. “The city attorney’s action today has nothing to do with protecting public safety, the building, or its residents,” Johnston said in The New York Times. “Instead, it’s an effort by the City of San Francisco to duck its responsibilities and avoid paying for the harm caused by Transbay Joint Powers Authority." There are estimates that the building to sink up to 31 inches, which could put extreme strain on the building, particularly since it is in a seismic zone. Herrera’s lawsuit alleges that the developer knew by 2008 that this would be the case—a year before it started selling units—and that they developer had a legal obligation to tell buyers about the sinking.
For the last couple of weeks, every night's been a party as the Millenium Tower plays host to Icons of Design, one of those opportunistic design events where hopefully everyone wins: High-end real estate is shown off, designers display their creative chops, charities get money, and the public gets a chance to wander through fantasy, "cost-is-no-object" spaces. For me, a trip up to the 52nd floor--the building has 60 floors, but my ears were already popping on the way down--was a chance to gawk at the latest in curtain walls. According to John Ishihara of Handel Architects, the unitized curtain wall system was built in China and snapped together on site. The bottom windows are operable, with top hinges so that rain doesn't come in, and they open up 4 inches. There is a one-inch gap between the two halves of the mullions, which enables a "trickle vent"--if you don't want to open the window, you can still let in fresh air but not the noise of the traffic below, muffled by the aluminum framing and internal baffles. Being able to open a window made this space, 52 floors up in the air, feel a little homier than your typical sleek condo. And the interior design? Most of the designers went for tasteful opulence, with luxurious fabrics and exotic woods standing in for last century's patterning and gilding. Local stars Martha Angus and Charles De Lisle evoked a more contemporary sense of fun. And then there was the dining room by Martin Richards. With two enormous photographs (of a yoga teacher and her rocker husband, a takeoff on ducal Renaissance portraits), framed by lamps held by hand sculptures, the room was a like a modern version of Cocteau's La Belle et La Bête. Wouldn't it be fun to hold a dinner party in a space like that? The Icons of Design showcase is open to the public on weekends through November 22.