SF Chronicle had a good overview[0] of what could be going wrong. From the article: The tower was built using a concrete frame instead of steel. Which is much

SF Chronicle had a good overview[0] of what could be going wrong. From the article: The tower was built using a concrete frame instead of steel. Which is much heavier - it puts about 4.75x the amount of pressure on the soil below the building (as compared to other steel framed buildings of similar size). It appears that some of the sinking could be due to weight and changing soil composition (less moisture and nearby excavation). [0] http://www.sfchronicle.com/bayarea/article/Sinking-Millennium-Tower-s-developer-built-9278364.php http://www.sfchronicle.com/bayarea/article/Sinking-Millenniu...