Leaning Tower of Pisa, A Magnificent Engineering Failure


The Leaning Tower of Pisa is a Magificent Engineering Failure

On this Date in History:  In Medieval Italy, a cathedral complex was begun in Pisa, Italy.   Ultimately,the complex would include four structures and be  known as the Campo dei Miracoli or Piazza dei Miracoli, which means Fields of Miracles.  If you are going to build a cathedral complex, it’s probably best to start with the cathedral and so the first building constructed was Duomo di Pisa.  It’s a fabulous example of Roman architecture and is set upon a white marble pavement.  Just to the west of the cathedral dome, the baptistry was constructed.  The third part of the Campo dei Miracoli was the bell tower, more properly referred to as the campanile.    While  the entire complex is considered by many experts to be the most spectacular assembly of Roman (Romanesque) architecture (though the cathedral is topped with an Islamic-style dome), the bell tower has become one of the world’s iconic structures and iconic engineering failure.

Photographer Dan Heller Provides a Look Inside the Cathedral in Pisa

The tower’s design called for a 185 foot tall, circular, eight-story column made of white marble.   The bottom floor consists of 15 arches with the next 6 stories containing 30 arches each and the top floor utilizing 16 arches for structural integrity probably more than asthetics.   A spiral staircase of 297 steps leads to the top floor which houses the actual bell chamber.  Truly, it is an astonishing engineering feat when one considers that construction was begun on this date in 1173.  The tower was perhaps the tallest of its type in all of Europe and was not built for any religious purpose.  Instead, it’s construction came about as a symbol of the wealth of the city.   This was the time of the rise in the city-state in Italy that eventually led to the Renaissance.  Pisa went to war with many of its city-state neighbors, including its chief rival, Florence.  The first order of business was the foot of the tower but the effort was halted due to the outbreak of war with Florence.  

Aerial View of Campo Dei Miracoli

In fact, construction of the tower was interrupted so often that it was not completed for 136 years.  Work was restarted in 1180 and the first 3 floors were completed 5 years later.  Funding ran out about that time because the city-state’s treasure was being put toward another war with Florence.  It was in that very year that the incomplete tower began to lean.  While the builders looked for a solution to the lean,  they put bells on top of the 3rd floor so that at least they would have a bell tower.  The battles with Florence and other city-states were frequent enough that construction was not restarted until 1275 when the wars were at such a manageable level that the work was able to continue for 9 straight years.  But, in 1284 the Navy of Pisa was decimated by that of Genoa partly due to the betrayal of Pisa’s own count, Count Ugolino della Gherardesca.  The count and his family were put into a prison tower and the folks in Pisa literally threw the key to the tower of Gualandi into the Arno River.  The disgraced family died of starvation and the tower has been known as the Torre della Fame (tower of hunger) ever since.  Dante started a story that the count was found gnawing on the bones of one of his dead kids and he has been referred to as the “Cannibal Count,” though recent evidence may have determined that the count was not a cannibal.   By 1319, the tower was finally completed.  But the symbol of Pisa’s power didn’t last long because in 1392, Florence bought the entire city-state of Pisa.  I suppose one might say that is when it became a tourist attraction.

Inside the Bell Tower

However, it is not known as the Campanile of  the Campo dei Miracoli or the Bell Tower of Campo dei Miracoli.   Instead, it is most often referred to as the Leaning Tower of Pisa.  No one knows for certain who designed the tower but he must have been someone of great skill, capability and guts.  But, it seems when they began the footing, they only went to a depth of about 10 feet on a dry stone bed.  When they finished the third floor and construction was halted, the building had sunk by about a yard (40 cm) and there was a lean of 5 cm.  If you think about it, a lean of a couple of inches is not that obvious to the naked eye so they had to have reasonably sophisticated capability to determine if a building was level. 

False Report of Tower's Demise

Short of tearing it down and starting over, the staircase design and weight of the material didn’t leave much room for fixing the lean.  When they got to the 6th floor, one side of the upper floors were raised to try and correct the lean which was then obvious to the eye as it had grown to 90 cm or about 7 feet.   Curiously, it is thought that the numerous delays in construction due to war or political unrest allowed the structure to settle to a relative state of stability.  Over the years, many people have come up with ways to correct  the lean.  One suggestion was to dismantle the tower and rebuild it at a different location.  If that had been allowed to come about, I doubt that the tower would be nearly as famous as it is today.  In the 1920’s,  a cement solution was injected into the foundation that may have provided extra stability.  Apparently,  Benito Mussolini also tried to add cement to the foundation but it sunk the clay. 

Cable Scheme Proposed to Save Tower

Today, the tower leans about 14 feet from center and it is estimated that the lean grows at about 1 mm per year.  Maybe it’s still settling.  It’s six feet shorter than it was originally and some estimates say that it will fall in about 175 years.    Efforts to find a permanent stablization method continues today, including the use of steel cables to hold up the Leaning Tower of Pisa.  That might keep it from falling down but it sure wouldn’t look too good.   The tower was closed from 1990 to 2001 while a solution was sought.  More stablization work was done and the tower reopened in 2001. Italian engineers claim the work means the Leaning Tower of Pisa won’t fall for 300 years.    Some say the 800 year mystery of the Leaning Tower of Pisa has been solved.  But, it does continue to lean further each year.     From time to time, the bell tower has been closed to the public but its open in the 21st century and remains an iconic tourist destination that gives people an extra reason to visit the small town of Pisa.  Perhaps the folks in Florence knew that they had their own Disneyland when they bought their enemy out.

Weather Bottom Line:  Hope you enjoyed the weekend weather because the heat and humidity is back.  We’ll be talking upper 90’s to near 100 and as the week goes on, the humidity will get worse and worse until Wednesday becomes pretty tough.   A front may get close enough on Wednesday to help destablize things enough and work with the afternoon heat to trigger some t’storms.  The ridge appears to re-establish itself on Thursday so that would mean more limited chances and then on Friday, we have another front that again gets close enough to raise the prospects of t’storms and rain.  Biggest difference between this week and last is that it doesnt look like the front will be able to make its way through and bring a break in the heat.

3 Responses

  1. Very nice post on the famous “Leaning Tower”. The whole story of the count eating his familys sounds a little far fetched to me. Wouldn’t they have succumbed to lack of water long before they died of hunger? Unless they gave them water but no food. That seems unlikely. My guess is that Count Ugolino was a pretty hated figure in Pisa and the story came along to further discredit him. We’ll probably never know for sure, I suppose. A pretty harsh sentence and a horrible way to die, that’s for sure!

  2. You make a good point about the Count. I suppose everyone was on Dante’s bandwagon and never gave it consideration until recent histroians decided it was time to take another look. Wouldn’t the tower look pretty lousy if they had to put up cables?

  3. The word “tacky” comes to mind. I once saw a scheme that someone concocted to build a giant statue next to the tower to hold it up. The statue would be functional yet not as unsightly as a bunch of ugly cables. That’s a tough situation though to try to stabilize something that heavy without messing up the aesthetics. I can only guess what a solid stone structure like that would weigh! I guess they need to call “Ramjack”!

    You going to be doing any weather again soon? I’m really sorry that I missed an opportunity to see you again in your true element. It was pretty great of Marc Weinberg to give you another shot. I guess I’m going to have to re-assess my opinion of Mr. Weinberg–that was a very nice and classy thing for those guys to do!

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