The MilleniumTower residential building, a 58-story luxury skyscraper located in San Francisco, USA, leans more than 7 centimeters each year as engineers scramble to find a solution.
Structural engineer Ronald O. Hamburger told a city conference Thursday that the 58-story Millenium Tower 197 meters Tall, is leaning 3 inches each year, reported the medium NBC Bay Area.
The tower, which stands in the financial district of San Francisco, next to the Salesforce Transit Center transportation terminal, was inaugurated in 2009 and in total it has already been tilted 66 centimeters northwestward.
Stabilization work on the skyscraper, which is sinking as it tilts, was suspended last summer, based on a data report showing that they were recorded 10 inch incline Y about 6 centimeters sinking during the repair work last year.
At the conference, the engineer proposed reduce the number of piles support under the tower from 52 to 18, which will be anchored in the bedrock, 76.2 meters below the tower, crossing a clay and sand soil that is compressing rapidly and on which the foundation of the building currently sits.
In a letter sent to the owners, Hamburguer explains that the building sank more than expected in the process of its settlement, when the installation of the linings and piles began during the repair work. According to the engineer, this was due to “vibration of the floors” and the “involuntary removal of excess soil while the piles were being installed.”