Did you know that the Leaning Tower of Pisa is empty from the inside and not a multi-story residential tower?
Can you imagine that a tower weighing 14,500 tons is built on foundations 3 m deep and installed on sand and silt?
Among the reasons why the tower did not collapse:
- The construction continued for 199 years, and the construction halt in it for a long time is one of the reasons that allowed the soil to compact, which reduced the rate of inclination, and thus the tower did not collapse completely.
- The clay soil helped and the main reason for the tower’s tendency not to collapse and its resilience in front of 4 earthquakes.
- The engineers calculated the center of gravity of the tower, and it was concluded from the calculations that the tower collapsed completely upon reaching a slope of 5.44 degrees.
- The tower was closed in 1990 at a tilt of 5.5 degrees, yet the tower did not collapse.
Attempts made to stop the tilt of the tower and not collapse:
Digging deep holes in the ground at a depth of 40 m, and installing the tower with iron cables through the holes. Liquid nitrogen was pumped, which led to the freezing of water in the soil and its expansion and contraction again, which led to the subsidence of the soil and the subsidence of the foundations, and consequently the slope of the tower at the rate of its inclination throughout these years.
They dug 361 holes and injected the soil with 90 tons of cement, which led to the tower’s tilt strongly. Finally, Soil Extraction was used in 1990:
- The soil was removed from the non-slanted side so that the tower tilts in that direction, then iron cables were used to fix the tower bases in the ground and the slope was reduced to 4 bikes, and this was what it was at the beginning.
- The engineers could have made it vertical, but they didn’t want to lose its fame and tourist value because of its tilt.
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- After that was completed, the tower was opened.
- It was confirmed that the tower could endure without any collapse for 300 years.
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