[ad_1]
The Leaning Tower of Pisa began construction in 1173 and started to lean by the second floor due to soft soil. After conservation efforts in 2001, the tower was straightened 17.7 inches and declared stable in 2008. Recently, engineers installed a system of tunnels and shafts to drain water and discovered a concrete foundation from 1828. The tower now has the same lean as it did in the early 19th century and is expected to remain stable for another two centuries.
Construction on the structure now known as the Leaning Tower of Pisa began in 1173, and by the time the builders completed the second floor, the tower had begun to lean, due to the soft, sandy soil underneath. Delayed by various problems, it took nearly 200 years to complete the Tuscan tower. And in the late 20th century, the tower was leaning 5.5 degrees, or nearly 15 feet (4.6 m) from the perpendicular. In the 1990s, Italian engineers feared the tower could collapse “at any moment”. The building was closed for eight years, as engineers hung tons of lead counterweights at the base of the tower and carefully cleared the soil around the non-sinking south side. The tower was straightened 17.7 inches (45 cm) by the end of conservation efforts in 2001, and in 2008 the tower was declared stable and stopped moving. Unexpectedly, the tower has self-corrected another 1.5 inches (4 cm) closer to perpendicular since 2001.
The Leaning Tower of Pisa loses momentum:
Engineers dug 20 liters of soil at a time around the base and installed a system of tunnels and shafts to drain water that kept the soil moist and caused the base to sink.
During the excavation, the remains of a concrete foundation poured in 1828 were discovered. Engineers created a more solid foundation for the tower by tying it to the foundation with large chains.
The tower, which attracts thousands of tourists every day, now has the same lean as it did in the early 19th century. At some point, though, the tower will stop correcting its roster, but it should remain stable for another two centuries.
