I watched them build a 22-story high rise on landfill (mud/sand) in the SOMA district of San Francisco—it was right next to my building. After demolition of the old structure (a 3-story apartment) and excavation, they did the following:
- Pump water out of the excavated ground. It was a slow drain, maybe 50 gallons per minute, but it ran for months.
- Drive dozens of 90 foot steel pylons into the site with an enormous pile driver.
- Pour the foundation over the pylons.
The Millenium Tower is more than double the height of that, at 46 stories, and it’s right by the water. But they used the same length of pylon. Mind-boggling.
- Pump water out of the excavated ground. It was a slow drain, maybe 50 gallons per minute, but it ran for months.
- Drive dozens of 90 foot steel pylons into the site with an enormous pile driver.
- Pour the foundation over the pylons.
The Millenium Tower is more than double the height of that, at 46 stories, and it’s right by the water. But they used the same length of pylon. Mind-boggling.