The Leaning Tower of The Leaning Tower of PisaPisa

By: Madison HusethBy: Madison Huseth

Construction & TiltConstruction & Tilt

Construction of this campanile began Construction of this campanile began at 1173. Pisa was a trading center at at 1173. Pisa was a trading center at the peak of its military might and the peak of its military might and artistic achievement. The Pisans artistic achievement. The Pisans white marble tower began to tilt white marble tower began to tilt even before its third story was even before its third story was finished in 1274.finished in 1274.

What it’s made out ofWhat it’s made out of

Engineer Bonanno Pisano failed to Engineer Bonanno Pisano failed to consider the consequences of consider the consequences of designing a 185-foot-tall tower with a designing a 185-foot-tall tower with a stone foundation only about ten feet stone foundation only about ten feet thick. This thin base rests on soft thick. This thin base rests on soft sand, rubble, and clay – hot firm sand, rubble, and clay – hot firm underpinnings for an almost 16,000 underpinnings for an almost 16,000 ton tower. The structure continued to ton tower. The structure continued to settle unevenly. settle unevenly.

Make up for tiltMake up for tilt

To make up for the tilt, builders To make up for the tilt, builders made each new tier a little taller on made each new tier a little taller on the short side – but the additional the short side – but the additional stone only made the tower sink stone only made the tower sink more. Upon completion in 1350, the more. Upon completion in 1350, the tower was leaning a full 4 feet, 7 tower was leaning a full 4 feet, 7 inches from vertical.inches from vertical.

Up in the BelfryUp in the Belfry

Up in the belfry, the weight of the bells caused Up in the belfry, the weight of the bells caused the structure to tilt even further. By the late 20the structure to tilt even further. By the late 20thth century tower was leaning more than 17 feet century tower was leaning more than 17 feet toward the south, and a rescue operation was toward the south, and a rescue operation was begun. Engineers removed soil from under the begun. Engineers removed soil from under the north side of the tower to even out the north side of the tower to even out the differences in the foundation. During the differences in the foundation. During the restoration, visitors were not allowed to enter the restoration, visitors were not allowed to enter the tower and climb the 293 – step spiral staircase to tower and climb the 293 – step spiral staircase to the top. The lean was reduced by more than 15 the top. The lean was reduced by more than 15 inches. Hard to believe? What else would you inches. Hard to believe? What else would you expect for a tower standing on what Pisans call expect for a tower standing on what Pisans call the Campo dei Miracdi – The Field of Miracles. the Campo dei Miracdi – The Field of Miracles.

More about the construction More about the construction

It took centuries to construct the Leaning It took centuries to construct the Leaning Tower of Pisa. It went on for 2 centuries. Tower of Pisa. It went on for 2 centuries. The third floor of the Leaning Tower of Pisa The third floor of the Leaning Tower of Pisa was constructed in 1178 when it began to was constructed in 1178 when it began to lean, and thereafter the construction lean, and thereafter the construction stopped. Four more floors were constructed stopped. Four more floors were constructed in 1272 to make – up for the inclination. in 1272 to make – up for the inclination. The construction stopped again until 1372 The construction stopped again until 1372 when the last floor of the Leaning Tower of when the last floor of the Leaning Tower of Pisa was built. In the same year, the bell Pisa was built. In the same year, the bell was finally installed.was finally installed.

Important HistoryImportant History The Leaning Tower of Pisa holds a significant place in the The Leaning Tower of Pisa holds a significant place in the

world history as well. Famous physician Galileo Galilei once world history as well. Famous physician Galileo Galilei once dropped two cannon balls of different masses from the dropped two cannon balls of different masses from the Leaning Tower of Pisa to demonstrate their speed of Leaning Tower of Pisa to demonstrate their speed of descent was independent of their mass. After some years, descent was independent of their mass. After some years, Italian dictator Benito Mussolini commanded the Tower to Italian dictator Benito Mussolini commanded the Tower to be erected. So cement was poured into its foundation but be erected. So cement was poured into its foundation but the consequences were disappointing as the Leaning Tower the consequences were disappointing as the Leaning Tower of Pisa sank further into the soft soil. Reflecting more on the of Pisa sank further into the soft soil. Reflecting more on the history of the Leaning Tower of Pisa, it would be interesting history of the Leaning Tower of Pisa, it would be interesting to know that during World War l l, the American forces were to know that during World War l l, the American forces were ordered to demolish all the towers in the city of Pisa ordered to demolish all the towers in the city of Pisa because of the threat of snipers in the city. All the towers because of the threat of snipers in the city. All the towers were demolished except for the Leaning Tower of Pisa were demolished except for the Leaning Tower of Pisa because of a last – minute order to retreat.because of a last – minute order to retreat.

Threat of CollapseThreat of Collapse

In 1990, the Leaning Tower of Pisa In 1990, the Leaning Tower of Pisa was closed as there threat of was closed as there threat of collapse. This was subsiding at the collapse. This was subsiding at the rate of 0.03 inches a year. Engineers rate of 0.03 inches a year. Engineers undertook a strengthening project undertook a strengthening project that decreased the lean by 17 inches that decreased the lean by 17 inches to about 13.5 ft. The work was to about 13.5 ft. The work was completed in May 2001 and completed in May 2001 and reopened for public in June 16, 2001.reopened for public in June 16, 2001.

Why is it Leaning?Why is it Leaning?

The Leaning Tower of Pisa may be The Leaning Tower of Pisa may be leaning because of a blunder leaning because of a blunder committed by 12committed by 12thth century engineers, century engineers, but it is still one of the most famous but it is still one of the most famous structures known across the world structures known across the world and will always remain so.and will always remain so.