Tilting San Francisco Tower Faces New Problem

San Francisco’s Millennium Tower, a 58-story residential high rise that has been the target of numerous lawsuits over its sinking, tilting foundation, is facing new problems: the building’s lean is changing the angle of some of its sewer lines, causing sewage backups, NBC CT reports. The sewer lines must slope at least 1/8 in. per foot for proper flow but, according to the designer of the project repairing the tower’s tilt, lines opposite the lean “will experience decreased slope and may become a problem.” The issue was raised when the building continued to tilt after work began to stabilize the foundation. The lean, now 22 in. — it was 17 in. when work started in May — is flattening the angle of some of the sewer lines by as much as 25%. The suggested solution is to adjust the level of hundreds of pipes, but that should wait until the building is stabilized. The foundation work began in November 2020 and, at the time, was expected to take two years. Engineers have found no signs of “distress” in the tower’s elevator system, the designer said.