The geology companion. Essentials for understanding the Earth / Спутник геолога. Основа для понимания Земли

Millennium Tower is a 58-story luxury high rise in San Francisco. It cost $350 million to build and contains units that start at $1.6 million and go up to over $10 million. The builders chose to sink support pilings 24 m (80 ft) into bay fill mud and dense sand rather than the 60 m (200 ft) needed to reach bedrock. Since the building was completed in 2009, it has sunk 38 cm (16 in) and is tilting 5 cm (2 in) to the northwest (Matier and Ross 2016). This is not just a concern to the 400 residents. Taxpayers have already spent $58 million building a buttress between the tower and the adjacent Transbay Transit Center that is under construction. The subsidence is not yet considered a safety issue, but residents are concerned.