PISA – “It’s still straightening,” said engineer Roberto Cela, gazing atthe Leaning Tower of Pisa gleaming in the autumn sunshine of northernItaly. “And many years will have to pass before it stops.”
The gravitationally-challenged landmark is leaning less after years ofambitious engineering work. Fortunately for the millions of tourists whocome here every year, the 57-metre (186-feet) tower remains beautifullyaskance.
The medieval bell tower, a symbol of the power of the maritime republic ofPisa in the Middle Ages, has leaned to one side ever since building startedin 1173 on ground that proved a little too soft.
The tower was closed to the public in January 1990 for 11 years over safetyfears, as its tilt reached 4.5 meters (15 feet) from the vertical,threatening to turn it into a pile of rubble.
“We installed a number of tubes underground, on the side that the Towerleans away from,” said Cela, technical director at the OPA, which looksafter Pisa’s main monuments.
“We removed soil by drilling very carefully. Thanks to this system, werecovered half a degree of lean,” he said.
Michele Jamiolkowski, an engineer of Polish origin who adopted Italiannationality, coordinated an international committee to rescue the landmarkbetween 1993 and 2001.
Engineering lecturer Nunziante Squeglia of Pisa University, who works withthe Surveillance Group that was set up after the rescue work, has beenstudying and measuring the tower for 25 years.
He says that the tower straightened by 41 centimetres (16 inches) until2001, and another four centimetres since then.——————————
*Still mysterious*——————————
To understand how the 14,500-tonne building is moving, measurements aremade as often as once an hour, some automatically using pendulums, somemanually using a surveyor’s optical level.
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“The tower tends to deform and reduce its lean in the summer, when it’shot, because the tower leans to the south, so its southern side is warmed,and the stone expands. And by expanding, the tower straightens,” saidSqueglia.
He explains that there are three pendulums, one dating back to 1935, whensystematic measurements began, although annual measurements began as farback as 1911.
“The tower was much more mysterious when I arrived, it wasn’t clear why itwas leaning, and increasingly leaning,” said Squeglia.
“It is a building that has been extensively studied for over 100 years butthere are still so many things to know,” he said, including the remains ofwhat looks like a domed roof inside the tower that is still unexplained.
Meanwhile, Cela predicted that the tower “will never be completelystraight”.
“When they were building it, there were attempts to straighten it (byadding stone on one side), so it has a slight banana shape.”
Singaporean tourist Alvin, who like many visitors is taking photos offriends ‘holding up’ the tower in the background, said he didn’t know aboutthe decreased lean.
“Oh I didn’t notice, is it because like everyone’s pushing against it?” hesaid, promising to try to push the tower back if it straightens too much. -APP / AFP
