Leaning Tower of Pisa is still straightening: Experts

Pisa, December 2 

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“It’s still straightening,” said engineer Roberto Cela, gazing at the Leaning Tower of Pisa gleaming in the autumn sunshine of northern Italy. “And many years will have to pass before it stops.” 

The gravitationally-challenged landmark is leaning less after years of ambitious engineering work. Fortunately for the millions of tourists who come here every year, the 57-metre (186-feet) tower remains beautifully askance.

The tower was closed to the public in January 1990 for 11 years over safety fears, as its tilt reached 4.5 meters from the vertical, threatening to turn it into a pile of rubble.

“We installed a number of tubes underground, on the side that the Tower leans away from,” said Cela, technical director at the OPA, which looks after Pisa’s main monuments. “We removed soil by drilling very carefully. Thanks to this system, we recovered half a degree of lean,” he said.

Engineering lecturer Nunziante Squeglia of Pisa University says that the tower straightened by 41 cm until 2001, and another four centimetres since then.

To understand how the 14,500-tonne building is moving, measurements are made as often as once an hour, some automatically using pendulums, some manually using a surveyor’s optical level.

“The tower tends to deform and reduce its lean in the summer, when it’s hot, because the tower leans to the south, so its southern side is warmed, and the stone expands. And by expanding, the tower straightens,” said Squeglia. — AFP