December 15: the world’s most famous construction mistake
2012/12/15 § 2 Comments
On this day in 2001 tourists were once again allowed into the Leaning Tower of Pisa.
The date marked the Tower’s official opening after an eleven-year, $27-million restoration project to stabilize (rather than correct) the famous lean. When the tower was begun in 1173, the builders, of course, intended that the campanile (for it is, afterall, the cathedral’s bell tower) be straight. After a few years of construction, when construction had reached the second or third-story mark, it started to tilt due to one bad choice: the soil was a mix of clays shot through with an aquifer. This is not great for foundations. In a second construction phase of 1272 builders attempted to even the structure by building whoppy, uneven floors. It didn’t work. They kept going. By the time the tower was compete in 1319 it had reached a height of about 186 feet at its highest point (the lowest high point was some three feet lower). And it kept leaning.
As is, regrettably, so often the case, later futzing with the building only made matters worse. In 1838, a thoughtful person, who wanted to reveal more of the finely carved foundation, dug around and prompted another precipitous lunge. Then Mussolini, big fan of ninety-degree angles and plumb lines, directed engineers to yank it to a perfectly vertical condition in 1935. They shot a bunch of concrete into the ground, and again, the Tower responded by tilting more. After much study in the late twentieth century, repairs began in 1990, removing soil under the high side and yanking it back about 18 inches.
The Tower is now believed to be stable, and non-dynamic, for the first time in its history. It’s once again open for visits, ensuring that the tour busses will keep disgorging daytrippers from Florence who come to see the tower, and take in the rest of the city (well, at least the cathedral and fancy baptistery) while they’re at it. If not for the lean of its campanile, Pisa would really have to fight for attention from the equally (some might say more) interesting cities of Genoa, Parma, and Bologna that are also within reach of Florence. Still, one vaguely regrets the correction of this unique dynamic building by removing the quality that, literally, has animated the tower for centuries. No longer actively moving, it’s a static mistake, no longer the danger choice for slow-motion thrill-seekers.
Image: it’s the tower (from this source)