Link #98: The Leaning Tower of Pisa Is Actually Growing Shorter on One Side!

5

 

Chain of Facts - A Connection of Facts

Link #98: The Leaning Tower of Pisa Is Actually Growing Shorter on One Side!

The_Leaning_Tower_of_Pisa
The Leaning Tower of Pisa. Image credit: McPig, (CC BY 2.0)

In our last post, we explained how lightning doesn’t always travel from the sky to the ground. We revealed that about 1 percent of lightning goes the other way and that many instances of ground-to-sky lightning are preceded by conventional lightning. The upward lightning usually originates from a skyscraper or tower, but the tower has to be taller than older constructions like the Leaning Tower of Pisa. In fact, the Leaning Tower of Pisa has actually been growing shorter for most of its life. How’s this possible? Read on!

Previous Link  in the  Chain of Facts
Next Link in the Chain of Facts




Has the Leaning Tower of Pisa Always Been Growing Shorter?

Pisa_Tower_Italy
La Tour de Pise depuis son jardin. Image credit: Gimli_36, (CC BY-SA 2.0)

The Leaning Tower of Pisa was actually growing shorter for most of its life. The tilt of the Leaning Tower of Pisa exists because one side of the tower has always been sinking into the ground. The tower was constructed in phases with the process beginning way back in 1173 and being completed in 1319.

Notably, the tower gradually sank on one side to a point where it was leaning at 5.5 degrees. However, because of the dangers involved, Italy asked for help from the world to fix the tilt of the tower in 1964. Multiple professionals came together to fix the tilt and succeeded by 2008.


Why has the Leaning Tower of Pisa Been Sinking over the Years?

Pisa_schiefer_turm_gewichte_1998_01
Leaning tower of Pisa – lead counterweights. Image credit: Rolf Gebhardt, GFDL.

The first phase of the construction of the Leaning Tower of Pisa involved the first two floors and lasted for five years. The foundation of the tower was laid at this time and it was only as deep as 3 metres.

In addition to this, the Leaning Tower of Pisa was constructed on a piece of ground with an unstable and loose subsoil layer. The subsoil is the layer of soil just below the topmost layer of soil on the ground.

The construction was halted for the next 99 years which caused the tower to get the slant but also allowed the layer of soil to stop moving and settle down a little more. This slowed down the tilting of the tower, but it still continued to happen till 2008 when it was stabilised for good.


How Was the Tilt of the Leaning Tower of Pisa Fixed?

It took a very long time for the Leaning Tower of Pisa’s tilt to be fixed. This was because one of the requirements was that the tilting of the tower be stopped for the foreseeable future.

During the second phase of the tower’s construction in 1272, it was decided to compensate for the tilt by making future floors disproportionate. What they did was make one side of floors longer and kept the other side shorter. This countered the tower’s tilt to a certain extent, but made the tower curve.

After Italy called for international help in the 20th century, experts like mathematicians, engineers and historians came together to discuss the best ways to fix the tilt of the tower.

The studies went on for 26 years before it was decided to straighten the tower by removing soil from the higher end. More soil was removed in 2008 causing the tower to become stable for the next 200 years.




Can you Guess the Next Link in the Chain?

What will be the next link in our Chain of Facts? Think you might know? Scroll down to add a comment below with your best guess.

Previous Link  in the  Chain of Facts
Next Link in the Chain of Facts

You can view the full list of links in the chain here.


Sources:

http://en.wikipedia.org/wiki/Subsoil
http://en.wikipedia.org/wiki/Leaning_Tower_of_Pisa#History_following_construction

LEAVE A REPLY

Please enter your comment!
Please enter your name here