A little over 3 years ago, reports surfaced that San Francisco’s luxury high rise, the Millennium Tower, has been consistently sinking and tilting since it was completed in 2009. Lawsuits have been underway for years involving dozens of lawyers from many different parties, but an expert panel has just approved a $100 million plan to keep the building from sinking and tilting any further.
Late last year, a permit application was submitted to the city to add 52 piles, driven roughly 250 feet into ground, deep enough to hit bedrock. The original foundation design called for 950 reinforced concrete piles installed around 90 feet deep, but were clearly not enough to keep the building stable.
Over the past 11 months, a 4 person expert panel met 11 times to discuss the plan, according to the San Francisco Chronicle. The panel was hired by the city.
Although the 58-story residential tower is currently leaning 17 inches to the northwest, the Chronicle reports that the city’s Department of Building Inspection does not classify these repairs as “mandatory.” They do, however, admit that continuing to allow the building to settle could cause mandatory repairs in the future.
The 52 additional piles will be spread across the north and west side: 22 on the north and the other 30 on the west. The idea is to shore up the sides that continue to sink and eventually the building will naturally straighten up.
Due to the site’s Old Bay clay, which can inflict uplift forces on the new piles over months and years, the panel does recommend that the building’s performance be monitored over a 10 year period by a Geotechnical Engineer, per the official letter from the review panel to the city’s building Chief Building Official.
Full story: Millennium Tower: Panel OKs $100M fix for SF’s tilting building | San Francisco Chronicle