Saturday, January 29, 2011

Pisa Tower In Italy

The Leaning Tower of Pisa, an eight-story, 185-foot bell tower in Pisa, Italy, was begun in 1173 and completed in 1350.

From the beginning, the tower leaned because of the way the foundation settled.

Throughout the building of the tower, architects and engineers tried to straighten it out and compensate for the lean.

Before the tower had a major renovation between 1990 and 2001, its lean had reached about 15 feet from the perpendicular, having continued to increase by about one-twentieth of an inch per year.

In 1990 the tower was closed and the bells silenced as engineers undertook a major straightening project. Earth was siphoned from underneath the foundations, decreasing the lean by 17 inches to 13.5 feet; engineers predicted it would take 300 years for the structure to return to its 1990 position.

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