"It's still straightening," engineer Roberto Cela observed, staring at the sparkling Leaning Tower of Pisa in northern Italy's fall sunshine. "And it will take many years until it quits." After years of intensive technical effort, the gravitationally challenged monument is leaning less. It has been leveled off with steel cables and poles, and its future stability improved by digging a new basement beneath its base.
The first thing to say about the Leaning Tower of Pisa is that it isn't really leaning. Or if it is, then the amount of lean is very small -- 0.3 degrees -- which for such a famous building is nothing. But since it's a tourist attraction, they straighten it out every day before opening up the site to visitors.
The second thing to say is that it's not actually the tower that's leaning; it's the soil under the tower that's tilted. If you look closely at the photo below you can see that the base of the tower is well below sea level. The land around it has been sinking over time due to erosion caused by rainwater running down the hill into a valley floor formed by previous collapses of this same hillside. The water flows underground toward the city center where it hits another collapsed section of street and rises again, only to repeat the process elsewhere in the city.
(Source: CBS News) Although it is not evident to the naked eye, the Leaning Tower of Pisa is not leaning as much these days. In fact, it's roughly an inch straighter than it's been for generations. The transformation took 12 years and was the outcome of a massive renovation operation. Before the work began in 1151, experts say that the tower might have leaned by as much as 4 inches.
The first thing you notice when you visit Pisa is its stunning appearance. The Leaning Tower dominates the skyline, towering over Piazza dei Miracoli (Piazza del Miracle). From here, visitors can see many other famous buildings including the Duomo di Pisa, which dates back to 1163. There are also several museums to explore along with various churches and courtyards.
The city is surrounded by beautiful gardens and parks so even if you cannot go inside any of the museums, there are still plenty of things to see and do outside the city walls. Visitors often walk around the edge of the Campo rather than use the entrance, which can be crowded with tourists. However, if you want to avoid the crowds, come at off-peak times like during school holidays or in the winter when the campo is only half full.
If you want to see the interior of one of the museums, you will need to pay an entry fee.
The Pisa Leaning Tower is not only one of the most iconic landmarks in Piazza del Duomo, but it is also apparently leaning about 1.5 degrees to one side. The cause of this alleged "damage" is unknown.
The tower was built between 1172 and 1278, and its appearance gives an impression of being poised to topple over. This isn't just visual flair: The Pisa tower actually leans outwards so that its base is as wide as its top. This allows the water that fills the moat around the base of the tower to drain away more easily.
The original tower was approximately 100 feet high. Over time, the weight of the stone cladding has been found to be less than the engineers thought, so they decided to add another floor. The new floor was placed directly above the old one, which causes the tower to lean in towards the center of gravity.
You can see both the original and the restored version of the Pisa tower on display inside the cathedral. There's also a video showing the tower from different angles.
The tower was stabilized as a result of restoration work completed between 1999 and 2001. Engineers placed weights on the structure's north end while removing earth from below, forcing it to sink back in that direction gradually. The Leaning Tower of Pisa still leans south, although at just 3.99 degrees. It is the only known example of an uprighted leaning tower.
In response to questions about the safety of the tower, the city government has published several reports on the subject. In 1987, it concluded that the tower was safe and did not pose a threat to those who visited it. More recently, it has reiterated these findings while also stating that if the tower fell over, it would likely cause damage near the ground but not kill anyone.
The stability of towers has been a concern for builders throughout history. They have used many techniques over time to make structures more stable, such as adding more floors or outriggers. The Leaning Tower of Pisa is an example of a tower that has been stabilized. Its stability is due to measures taken during renovations in 1999-2001 that included placing weights on the structure's north end and removing soil from beneath it in an effort to make the tower lean further toward the south.
Towers have collapsed for many reasons. Sometimes this occurs because of accidents such as when a visitor climbs into a standing tower but fails to declare his intention to climb.
(Reuters) - Rome According to an expert who has been monitoring the famed Italian tourist attraction, the leaning tower of Pisa has been properly stabilized and will be safe for at least 300 years. "The base of the tower has been reinforced with new concrete beams that should last for hundreds of years," said Professor Giuseppe Bertolini, a geomechanics professor at the University of Bologna who has studied the problem for decades. In the past, the tower has been known to lean up to 3.9 degrees, but it has not collapsed completely. The latest report on its safety was published in 2000 when another expert concluded that the tower was still stable but needed repairs to the foundations.
The tower of Pisa was built between 1173 and 1268 as the main monument of the city's most famous church, which had been destroyed by an earthquake several months before it was completed. The building process continued after the original architect died, with different groups working on it separately. It is estimated to contain about 2 million cubic feet of stone, and the total weight is more than 22,000 pounds (10,000 kg).
The tower has always been a source of controversy because it doesn't appear to be aligned with either the sunrise or the sunset. This means that it must be leaning either north or south.