• Presented By:• Robert Moore• Brandon Farrell• Nick Falvo• Jack Kopmann• Adam Croker

Originally an Art Project Free standing bell tower

for neighboring Cathedral Construction began in

1173. Lasted 177 years due to

constant setbacks After three floors were

constructed, constant battles halted construction for nearly a century.

Original Architect: Bonanno Pisano.

The ground where the tower was built consisted of soft sandy layer on top of a layer of marine clay

Tower design only allowed for a three meter deep foundation.

After the third floor was installed, the building began to sink on one side. Giving the tower its famous lean.

Pisa had originally been a port city in Medieval Times

Land a spongy mixture Surface layer (10m deep)

accumulated fluvium from the River Arno

Sediments had compacted unevenly over life span of river

Pancone Marine clay – fine sands and shells (20m deep)

Alternated layers of sand and clay (70m deep)

The initial solution during construction was to make walls on the leaning side taller than the other side to compensate for the lean.

As a direct result, the tower is curved.

In 1934, concrete was injected into the foundation. The cement seeped into the clay base and exacerbated the problem.

In 1964, the Italian Government requested an immediate solution. Six hundred tons of counter-weights were added to straighten out the tower.

In 1993 the tower was closed to begin stabilization.

Cables were used to fix the tower in position during this process.

41 parallel corkscrew drills were used to remove approximately 38 cubic meters of sandy soil.

The tower then settled on the marine clay layer that was underneath, and the clay hardened.

This reduced the lean 50 cm and reverted the tower back to the state it was in in 1838.

The tower is said to be safe and stable for another 200 years.

The foundation was inevitably the flaw in engineering.

The foundation was only 3 meters deep and laid on very soft soil.

This could have been easily avoided by removing soft soil and making the foundation deeper.

Vezzosi, Guglielmo. "Leaning Tower of Pisa: They have tried for 700 years to Correct the Inclination." Endex Web Page. Sept. 1995. Web. 25 Jan. 2010. http://www.endex.com/gf/buildings/ltpisa/ltpnews/nazione4.htm

Barker, Don. "Stabilizing the Leaning Tower." ArchitectureWeek - 2010.0120. 21 July 2001. Web. 25 Jan. 2010. <http://www.architectureweek.com/2001/0718/news_2-1.html>.

Moore, Malcolm. “ Leaning Tower of Pisa is Saved from Collapse.” Telegraph 28 Jun. 2007 Pullella, Phillip. “ Leaning Tower Safe for 300 Years.” Rueters 28 May 2008 Nakamura, Yutaka. “Dynamic Characteristics of Leaning Tower of Pisa Using Micrometer.” Japan

Conference on Earthquake Engineering 1999. <http://www.sdr.co.jp/papers/pisa.pdf>.