The Millennium Tower located at 301 Mission Street in San Francisco, California opened in 2009 and is fifty-eight stories high. It is comprised of expensive apartments with price tags in the millions. “Yet for all its curb appeal, the building has, quite literally one fundamental problem: it’s sinking into mud and tilting towards its neighbors” reports John Wetheim of CBS News in the 60 Minutes segment about the condition of the tower “San Francisco’s Leaning Tower of Lawsuits.”
In the Tower’s basement along columns that protrude from the foundation of the building there are stress gauges lining the walls illustrating cracks with slow growth which is cause for concern. The tower is tilting a total of 14 inches toward the northwest and has sunk 17 inches so far. Petar Marinkovic, an engineer for the European Space Agency estimates that the tower is sinking 1.5 to 2 inches per year.
Jerry Cauthen, a local engineer, weighs in on what he believes is the cause of the sinking and leaning; it was built from concrete instead of steel. “Concrete is often cheaper. And it’s just as good, but it is a lot heavier. And so you got to design your foundation and your sub-surface to support that higher weight.” A local geotechnical engineer, Larry Karp agrees stating that the foundation of a building of this size and weight should be on solid rock (bedrock). The Millennium Tower is sitting on layers debris from the 1906 earthquake, a gold rush landfill, as well as clay, mud, and sand.
There over 20 parties involved in the Millennium Tower lawsuits so far. Solutions to “fix” the tower’s issues range from removing 20 stories from the top of the building to perpetually freezing the ground beneath the building. There are also ongoing mediation talks to determine the feasibility of drilling down to bedrock under a building where a thousand residents are still upstairs.