1. The Leaning Tower of Pisa What went wrong?!

2. So What Will We Talk About? A brief history of the tower. Why the structure failed. The reason it still stands. The attempts to straighten the tower. The reason it still leans.

3. The History In Italian, it is called the Torre Pendente di Pisa It is the bell tower of the town’s cathedral. Today it is 186 ft tall, with a 13 degree tilt.

4. History (cont’d): the construction Construction began in 1173 and continued off and on until 1372. Political crises caused breaks. Used multiple architects. First began tilt in 1178 with 3rd floor.

5. So… What happened Engineering was often trial and error due to lack of technology. The foundation was poorly constructed and was only about 3 meters thick. Built on an ancient riverbed just 6ft above sea level, made up of weak sand and clay.

6. The first lean of the tower was South. After trying to even the floors, it leaned North.

7. This is an over exaggerated picture of the plan to make it straight

8. Why hasn’t it fallen down? The soil compacted and settled due to the length of construction Without the break the tower would have fallen. It was built of limestone, which can handle more stress than most stone.

9. Attempts to Straighten the Tower Mussolini drilled and filed holes in the base with concrete, this made it tilt worse. (1934) Became unstable forcing the Italy government hired several engineers to stabilize it. (1964)

10. Problems… Was forced to close in 1990 due to increasing tilt. Later, it was stabilized by removing 40 cubic meters of soild from the raised end. Reopened to the public in 2001.

11. Why is it still leaning? Engineers decided not to straighten the tower for tourists. Instead, they gave it the relatively stable tilt of 13 degrees. It is believed to stand for at least another 300 years.

12. So, We talked about: The history and construction. The poor foundation which lead to the lean. That the solid compacted over time letting it stand. It still leans for a reason

13. The End Thank you