Foundation Problems and the Leaning Tower of Pisa
For years Atlas Piers has used the Leaning Tower of Pisa as our company logo. We went through the trouble of having someone modify it just for us so we could copyright it. But one question I get a few times a week is – how do you fix that?
The tower of Pisa was built in 1173 and was intended to stand vertically. But due to poor foundations and poor soils, the tower began to lean shortly after construction began. For this reason, construction was halted in 1178, resumed in 1272, halted in 1284…and in 1319 the seventh floor was completed.
Because of the lean, when construction was resumed in 1272, the floors were designed to be taller on one side than the other, and thus the tower actually has a curve to it.
Efforts made to stop settlement/leaning:
- 800 tons of lead were installed on one side to stabilize the lean.
- Bells were removed to relieve some of the weight
- Cables were installed to help prevent leaning
- 50 cubic yards of soil were removed from the high side of the tower (1990). (Engineers said it would be stable for 300 years)
- More dirt (77 tons of soil) were removed (2008) to stabilize the movement. (Now the engineers say it will be stable for 200 years)
We can learn from those building 800 years ago that if you have a poor foundation on bad soils, you will have settlement issues. It’s amazing that after all these years builders still make the same mistakes. Foundation problems of old are not that unlike foundation problems of today.