Wayback Wednesday: Leaning Tower Of Pisa 1173
Photographer
Source
Wikimedia Commons
04-02-2022
Eight hundred, fifty years ago, today…
The Leaning Tower of Pisa (torre pendente di Pisa…in Italian) is the campanile or freestanding bell tower of Pisa Cathedral. It is known for its nearly four-degree lean, the result of an unstable foundation. The tower is one of three structures in the Pisa’s Cathedral Square, which includes the cathedral and Pisa Baptistry. The tower has 296 or 294 steps. [The] seventh floor has two fewer steps on the north-facing staircase.
The tower began to lean during construction in the 12th century, due to soft ground, which could not properly support the structure’s weight. It worsened through the completion of construction in the 14th century. By 1990, the tilt had reached 5.5 degrees. The structure was stabilized by remedial work between 1993 and 2001, which reduced the tilt to 3.97 degrees.
Construction of the tower occurred in three stages over 199 years. On January 5, 1172, Donna Berta di Bernardo, a widow and resident of the house of dell’Opera di Santa Maria, bequeathed sixty soldi to the Opera Campanilis petrarum Sancte Marie. The sum was then used toward the purchase of a few stones which still form the base of the bell tower. On August 9, 1173, the foundations of the tower were laid. Work on the ground floor of the white marble campanile began on August 14 of the same year, during a period of military success and prosperity.
The tower began to sink after construction had progressed to the second floor in 1178. This was due to a mere three-meter foundation, set in weak, unstable subsoil, a design that was flawed from the beginning. Construction was subsequently halted for the better part of a century, as the Republic of Pisa was almost continually engaged in battles with Genoa, Lucca and Florence. This allowed time for the underlying soil to settle […], [otherwise], the tower would almost certainly have toppled.
There has been controversy surrounding the identity of the architect […]. For many years, the design was attributed to Guglielmo and Bonanno Pisano […]. A 2001 study seems to indicate Diotisalvi was the original architect, due to the time of construction and affinity with other Diotisalvi works, notably the bell tower of San Nicola and the Baptistery, both in Pisa.
Between 1589 and 1592, Galileo Galilei, who lived in Pisa at the time, is said to have dropped two cannonballs of different masses from the tower to demonstrate that their speed of descent was independent of their mass, in keeping with the law of free fall.
During World War II, the Allies suspected that the Germans were using the tower as an observation post. Leon Weckstein, a U.S. Army sergeant sent to confirm the presence of German troops in the tower, was impressed by the beauty of the cathedral, and its campanile and […] refrained from ordering an artillery strike, sparing it from destruction.
The tower has survived at least four strong earthquakes since 1280. A 2018 engineering investigation concluded that the tower withstood the tremors because of dynamic soil-structure interaction. [The] height and stiffness of the tower, combined with the softness of the foundation soil, influences the tower’s vibrational characteristics in such a way that it does not resonate with earthquake ground motion. The same soft soil, that caused the leaning and brought the tower to the verge of collapse, helped it survive.
Wikipedia Summary
***The ceremony, for the 850th anniversary of the foundation of the Tower of Pisa, was started, today and runs all year to August 9, 2024.
850th Anniversary (Turismo.Pisa.it)
OPE (Opapisa.it/en/)
The Leaning Tower Of Pisa Was Once Tilting Dangerously (CNN/Sharon Braithwaite/August 9, 2023)
Cosmic-Observation 
August 9, 2023 at 9:42 PM
The leaning tower of Pisa is quite remarkable. I was there twice, most recently in 2014. During my second visit, it was closed to the public. During my first visit in the early ’80s I climbed on top. Going up and down felt odd.
LikeLike
August 10, 2023 at 1:39 PM
Wow. I’ve never talked to anyone that has been in it or to it. I’d love to see it, walk in it. I imagine walking in it, at an angle, would feel odd.
The only comparison I have is the Wizard of Oz/Land of Oz Dorothy house in our NC mountains. It is a specially-designed house, where the front of the structure is created like Dorothy’s house in the movie. As you walk thru it, into the back, they have speakers lining a stairway that project tornado sounds with music, like the movie. You go down, then up, again. You come out of the stairs into the back side of the house and the floors are all messed up…you can’t walk a straight a line without stumbling all over the place. Rooms & furniture, identical to the front, are torn up and debris is everywhere. It is extremely disorienting, particularly if you are a kid. I walked thru that house with my parents in 1973 and it scared me.
I went back to the Land of Oz in 2017 and the house has been re-designed. The messed up floors were taken out and they were still rebuilding the park after decades of decay.
LikeLike
August 10, 2023 at 7:44 PM
I guess some lawyer realized broken up floors could become a huge liability!
LikeLike
August 11, 2023 at 1:08 PM
Pretty much. The original configuration was built in ’69-’70.
LikeLike
August 10, 2023 at 11:05 AM
Lulu: “Sounds like the tilty tower stands up to earthquakes better than some of the stuff we have here in California. Go figure!”
LikeLike
August 11, 2023 at 1:08 PM
I agree, Lulu.
LikeLike
August 12, 2023 at 6:38 PM
That is something I had no clue about. Thanks that was interesting. It took them until the 90s to stabilize it? Although there is no way in hell they would straighten it up completely.
LikeLike
August 12, 2023 at 7:14 PM
Not with the ground its built on.
LikeLike
August 12, 2023 at 7:17 PM
But even if they could…they wouldn’t…thats the whole appeal.
LikeLike
August 12, 2023 at 10:06 PM
Well, they have dug under it to straighten it a bit but, it will never be upright. I would love to go there for the 850th, year long celebration.
LikeLike
August 12, 2023 at 10:35 PM
That would be cool…I’ve never been to another country but I want to one day.
LikeLike
August 12, 2023 at 11:49 PM
Yeah. Me, too. Never been out of the US.
LikeLike
August 12, 2023 at 10:59 PM
Reminds of the library .. think in Indiana.. that didn’t take into account the weight of the books in their foundation calculations. To the Pisa’s credit..still standing, just a bit drunk.
LikeLiked by 1 person
August 12, 2023 at 11:51 PM
Wow. Is the library sinking?
LikeLike
August 16, 2023 at 12:05 AM
It did for a while until the ground compressed enough.
LikeLike