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Pondering Pisa

Posted by johnreynolds on June 24, 2005 at 5:41 AM PDT

If I asked you to list the most famous structures in the world, the Leaning Tower of Pisa would probably show up in your top 10 responses.

Like the Eiffel Tower or the Statue of Liberty, the Leaning Tower (Torre Pendente) is a major icon of the Euro/American culture that "everybody" knows about.

In early June I caught my first glimpse of Torre Pendente while driving into Pisa on the not-quite-two-lanes-wide road from San Giuliano Terme (driving on Italian roads is an adventure on its own). The tower came into view unexpectedly, and I was quite simply delighted. The reality of seeing something in person that I’ve known about all of my life was a great rush (I felt the same way the first time I saw the Washington Monument).

My wife, Teri, and I are wanna-be world travelers, and this June was our first excursion beyond North America. We spent two weeks in Tuscany, staying at an agriturismo just outside the small town of Calci. Our apartment was very close to Pisa, so we just "had" to make the standard tourist pilgrimage to "The Field of Miracles".

No doubt at this point some of my less patient readers are wondering why-the-heck I am blogging about my Tuscan vacation on Stick around, I’m getting there…

We arrived in Pisa very early to beat the crowds, and I had an excellent opportunity to experience the tower up-close-and-personal. Tacky over-commercialization aside, the tower and related structures are definitely worth a visit… but almost immediately something deep inside my gut started nagging at me. The tower is pretty neat, and obviously a tourist cash-cow, but as I stood before the tower the engineer in me kicked in and my inner voice started screaming:

"Why didn’t they start over?"

LeaningTower image

Most tourists get their picture taken in front of the tower. Almost all tourists pose as if they are holding the tower up. You will note that I am pushing the tower down.

Before any Pisans flame me: I love your tower. Its whimsical nature is enthralling, and the extreme measures that have been taken to save it are a testament to the dedication, creativity and resourcefulness of your citizens. My comments are those of an engineer who has endured way too many critical projects built on poor foundations.

You already know that the tower leans, but you may not be aware that the tower started leaning long before it was completed. We aren’t witnessing the results of a hidden flaw that appeared long after the project was completed, we’re witnessing the results of continuing to build on a known flaw for tens of decades after the flaw became apparent (the foundation is inadequate for the lousy soil at the building site).

Here’s a short history of the tower’s construction and projects to keep it standing:

  • 1173 to around 1180: The first four stories were built. Leaning was already evident by the time the base and 1st floor were finished. The tower was unwittingly built on the soft silt of a buried riverbed, and the foundation was only 13 feet deep.
  • 1272: After almost a century, the next three stories are added. To compensate for the lean, the three stories are angled opposite the lean.
  • 1350-1372: The belfry is added, also angled to counteract the lean.
  • 1550: The base is reinforced to counteract the slow fall. To some extent this is successful.
  • 1838: Ground water is pumped out. The intention is to further stabilize the base, but the result is an accelerated rate of fall.
  • 1990: Thirty million dollars is spent to stabilize the tower. A 600 ton counterweight is added with little effect. The breakthrough comes when 60 tons of faulty soil is pumped out from under the foundation.

As an engineer, I have to say that back in 1272 somebody should have said: "Let’s start over".

(Marketing people disagree: If the Pisans had started over on the tower, Pisa would have lost a unique tourist attraction (there are hundreds of towers that don't lean in Tuscany). But the marketers are speaking from today’s perspective.)

The tower was commissioned to demonstrate the might and power of the Pisan city-state. A crooked tower doesn’t meet that goal, and the original design flaw resulted in exorbitant maintenance costs and Herculean efforts to stave off total collapse.

Why does this sound so familiar?

By visiting Pisa I became aware of a bond between Renaissance engineers and myself (and my peers) that I had not imagined before:

  • Renaissance engineers were asked (or forced) to build on foundations that they knew were flawed
  • Renaissance engineers had to deal with "legacy systems"
  • Renaissance engineers had to implement "quick-fixes" that made the original problem worse
  • Renaissance engineers had to expend great effort over many years to patch and maintain defective projects (instead of starting over)

Renaissance engineers would find some aspects of today’s IT workplace very familiar.

Let’s face it; engineers will always be in a tough spot between the demands of their customers and “doing the right thing”. I’m sure that at least some of the Pisan engineers wanted to start over as soon as the lean started; I’ll bet that some of them were worried sick before the foundation was even begun. The Field of Miracles is a lousy building site, and they knew it. But what could they really do? The client said "build it here", and probably balked at the cost of the foundation. Why spend good money on a part of the building that nobody would ever see?

So as an engineer, what do you do when asked to "build on a lousy site"?

Many times I have told my clients that they were nuts. On most occasions I have convinced clients that their objectives could be met in a better way. Other times, I ended up looking for another job. I’m sure that I "just did what I was told" a few times, but not often; I have the luxury of living in a time and place where changing jobs is fairly easy. I don’t think my Renaissance compatriots were as lucky.

On a more positive note, despite the flaws and frustrations, all of the engineers who worked on the Leaning Tower will be remembered as contributing to something truly special. As an engineer I see flaws, but as a "normal" human being what I see is a truly unique and memorable piece of architecture.

I hope that someday something that I have worked on becomes as significant as Pisa’s tower.

I also hope that some day customers will stop asking engineers to build on lousy sites… but I’m not going to bet on that wish coming true.

(Cross posted at The Thoughtful Programmer)

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