Thankfully, for anyone who has visited Pisa recently, the Italians have developed their remedial engineering skills considerably over the last few hundred years meaning the infamous tilting tower is now well set at its current angle for at least the next three hundred years or so.
Almost as soon as work started on the bell tower of Pisa Cathedral, more commonly known as the Leaning Tower of Pisa, the mediaeval masons realised they had made a serious error of judgement. The first few courses subsided, leaving them to try and rectify a growing tilt problem by stacking up one side of the tower with more layers than the other. Ever since, engineers have battled against the centuries, poor soil and the stubbornness of those mediaeval masons to straighten things out.
Michele Jamiolkowski
More to the point, modern engineers have rung the changes and have halted the campanile’s increasingly threatening angle enough to present any future Galileo with a reasonably legendary experimental platform from which to perform gravitational experiments. Speaking at the 32nd World Geological Conference in Florence, Michele Jamiolkowski of Turin University laid to rest concerns that the tower might one day crash to the ground, effectively wrecking a centuries-old landmark and creating a hole in the Italian tourist industry that might never be filled again.
The Tower was closed to the public in 1990 when engineers noticed its lean was increasing at an alarming rate of one millimetre each year. Jamiolkowski, who is in charge of the restoration operation, says his team’s efforts halted this motion in September 2003. But, additional bracing work and underpinning of the foundations have consolidated the tower still further and it is once again open to the public.
A tilt too far (Photo by David Bradley)
Digital straightening on the Tower (photo by David Bradley)
Further reading
Leaning Tower of Pisa official website
http://torre.duomo.pisa.it/index_eng.html
32nd International Geological Congress
http://www.32igc.org/home.htm