Holding up process of the Leaning Tower of Pisa is way better than expected

The death knell for tourist photos.
Nergis Firtina
Piazza del Duomo, Naples.jpg

Began constructed in 1173 and completed in 1372, The Leaning Tower of Pisa, or simply the Tower of Pisa, has been the symbol of Italy for centuries. It is one of the biggest tourist attractions, and you have likely seen many photos of tourists trying to make the Tower of Pisa vertical with their hands.

The Leaning Tower of Pisa and the neighboring cathedral, baptistery, and cemetery were included in the Piazza del Duomo UNESCO World Heritage Site in 1987, and experts are trying to preserve it.

As ANSA (Italy's National Associated Press Agency) reported last month, Opera Primaziale Pisana's preservation project has continued more than expected.

 "Considering it is an 850-year-old patient with a tilt of around five meters and a subsidence of over three meters, the state of health of the Leaning Tower of Pisa is excellent," said Opera Primaziale Pisana.

It was closed in 1990

After more than two decades of stability research and in response to the dramatic collapse of the Civic Tower of Pavia in 1989, the tower was abruptly closed to the public on January 7, 1990. The bells were taken off, and cables anchored several hundred meters away wrapped tightly around the third level to lessen the load. Homes and apartments near the tower that might fall were evacuated for everyone's safety.

Shortly thereafter, the tower was closed to the public. The Italian government enlisted a group of experts, chaired by civil engineer Michele Jamiolkowski, to work out how to save it. They thought about injecting cement beneath the tower but decided that was too risky and instead tried anchoring the north side down with 900 tons (816 metric tonnes) of lead weights to counterbalance the sunken south.

Holding up process of the Leaning Tower of Pisa is way better than expected
Laser scan of the Tower of Pisa.

According to the surveillance group led by Salvatore Settis, Carlo Viggiani, and Donato Sabia, the tower has lost 4 cm of its tilt in the last 20 years, and its health is better than predicted by an international committee coordinated by Jamiolkowski between 1993 and 2001, which planned and coordinated consolidation work.

The non-profit Opera Della Primaziale Pisana provides funding for the group's activities, which include monitoring the tower, enhancing conservation efforts, and advancing the academic study of the structure. According to at least one Italian authority, modern engineering will eventually cause the tower to straighten up.

Engineering of The Tower of Pisa

The Tower of Pisa is 55.86 meters tall, weighs 14,700 tons, and extends 3.9 meters vertically with an approximate 4° incline. The Italian government requested assistance in 1964 to stop the Tower of Pisa from collapsing.

In 1173, the architect Bonanno Pisano began work on the first level, which was encircled by 15 white marble columns with classic capitals and blind arches. Due to the unstable subsoil on which the tower was built, the tower bent 2 inches (5 cm) to the southeast during the construction of the third level in 1178, thereby ending its construction. This period was critical because it allowed the ground to settle, without which the tower would have collapsed.

Giovanni di Simone began construction 100 years later, attempting to compensate for the tower's inclination by vertically erecting four stories. However, the results were not as intended, the bell tower was still tilting, and the works were halted once again. A plummet deviation of 56 inches (1.43 m) was measured in 1298, and 60 years later, it had grown to 1.63 m. Tommaso Pisano continued work on the bell tower, which was completed in 1372.

The slope of the tower slowed over the ages, and it is thought that its weight was a crucial element in allowing the edifice to stabilize. The first renovation was completed in 1835 by architect Alessandro Gherardesca, who removed the filthy dirt and replaced it with a marble base.

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