Engineering Failures:The Leaning Tower of Pisa By Logan Foster
History• The Tower of Pisa began construction in 1173.• There’s been a great deal of controversy over who the actual architect behind the tower, and nobody really knows who masterminded it.• The tower took 174 years to complete.• It’s said that Galileo dropped two cannon balls of different masses from the top of the tower to test his theories about gravity, but the only word on this comes from his secretary, so it may only be a myth.
Epic FAIL • The major problems began when the construction of the third floor of the tower began in 1178. • The original foundation was only 3 meters (roughly 10 feet) deep and it was set in weak, unstable soil, which caused the tower to begin leaning to one side. • Construction was immediately halted, for fear that the tower would fall.
The Solution• For the next century or so, Italy was involved in several wars and the project was ignored, which thankfully gave the soil time to settle.• Had this not happened, the tower would have toppled for certain.• In 1272, construction was resumed, under the architect Giovanni di Simone. In the hopes that he could compensate for the tilt, he had workers build the tower with the floors taller on the side opposite the tilt. As a result, the tower is curved.
The Solution (pt. 2) • Construction was halted again in 1284. • The bell-chamber was finally added in 1372, almost two centuries after construction began. Eventually seven bells were added, one for each note on the musical scale, the last installed in 1655. • The tower is today anchored with steel cables and lead weights, which has rectified the problem (for the most part.)
Today• Today the ‘Leaning Tower of Pisa’ is among the world’s most popular tourist attractions.• The final tilt of the tower was stopped at 5.5 degrees, and thanks to strengthening of the foundations and a restoration program that is in effect, architects predict that the Tower will be around for many centuries to come.