Sunday, June 16, 2013

Pisa - Celebrating Repeated Mistakes

We have spent the morning walking around a site that Mussolini thought was a national disgrace. He thought it humiliating that Italian engineers could not get rid of the lean in the Leaning Tower of Pisa. Undoubtedly, the site is a disgrace for the Italian engineers... but the international tourists just love the site. Each day thousands upon thousands ask the same questions... why doesn't it fall down... why did they build that crazy lean... will it finally fall... etc, etc. They ignore the other three Pisa towers that have leans... they just go bananas about this one. The story behind the Leaning Tower is interesting... and starts in the early 12th century. 

Donna Berta di Bernardo was a pious woman who wanted to buy her way into the heavenly kingdom... and upon her death in 1172 bequeathed her earthly possessions to purchase stone to form the foundations for a tower... to complement the marvellous cathedral the city of Pisa had built just outside the old city. Her bequest was enough to purchase stone for only 5 metres of foundations... perhaps sufficient for a tower built on rock... but not enough for foundations of a tower built on marshy ground. They dug the foundations and saw that the site was very wet and covered some soft clay that was likely to compact over time. Any responsible engineer would have withdrawn building permission... but these creative thinkers said, "She'll be right! We'll just limit the height to 2 stories. The change of plans left plenty of money to buy the best of heavy marble to complete the construction. The building was completed... everyone was happy with a tower of 2 stories... even though it was shorter  than the Cathedral itself.

 For 5 years the tower stood upright... and the church people started to think positive thoughts. Imagine how beautiful it would look if we add a third story... it would balance the size of the cathedral so much better... anyway, it looks like the clay has settled... so it should be alright." Big mistake... as soon as they built the third story, the structure started to tilt... only a little bit. Work was called to a halt for 100 years. The city fathers tried to find out who were the responsible builders... when they searched, they found the construction certificates were unsigned... no one could remember the name of the prime builder... the subcontractors reckoned the plan was to have a tilt all along... to add to the aesthetics. Anyway, there were wars to fight... empires to retain... you can't get too excited by a leaning tower... in fact, the citizens got used to the lean... and saw the lean as an expression of independence. 

After the 100 years, a new generation of engineers saw that they were smarter than their forefathers... and by applying new technology... could straighten the tower while extending its height by another 4 stories. Well, the straightening didn't happen... although the banana shape introduced in the top 4 floors proved to be a good idea. But what happened next was just crazy! 

Alessandro Della Gerard had the bright idea of digging a ditch round the tower... as a way of displaying those 5 metres of foundation stone. They started to dig the ditch... waterstarted to appear... and some citizens thought the lean was getting worse. 

Mussolini had a go at correcting the lean... by placing a heavy counterweight into the base of the tower. Again, a good idea that helped with stability... but not enough to correct the tilt. In very recent times our current generation of engineers have had their go... computer models and all. They all agree that they have done a very good job... but the tilt persists. 

So, this jolly tower has been fascinating people for over 800 years... fascinating them with engineering incompetence. Even today, the building gets people to act in peculiar ways... like having their photo taken in a perspective that appears they are holding up the tower... stopping it falling over. Now, if you were the first to think of this photography trick... you could feel very pleased with yourself. But when hundreds are duplicating the same trick... and you line up to be the 101st... what is the point?

No comments:

Post a Comment