According to experts, the renowned tower of Pisa will continue to tilt for at least another 200 years. It may even remain erect, or almost so, indefinitely. Several ill-advised construction projects hastened the Leaning Tower's very gradual collapse throughout the ages; it inclined 5.5 degrees, its most acute angle ever, in 1990.
The tower has been called the "Eiffel Tower of Europe" because of its resemblance to the famous French tower. But while the Eiffel Tower is straight, the leaning tower of Pisa has a slight curve to it. The reason for this curvature is that its original builder, Giorgio Pisano, was not a trained architect but an artist who used mathematical formulas to calculate the best way to arrange his stones.
Pisa's mayor has said that the city government no longer has the money needed to repair the damage done by tourists who climb on the leaning tower. In fact, only about 10% of its visitors actually visit the tower itself. Most just take photos next to it.
The tower has been undergoing maintenance since 2009, when workers removed some of the top layers of stone to expose the lighter gray heart of the tower which is made from porous Tolfa limestone. This limestone is found near Pisa and other parts of Italy and requires regular maintenance if it is to be kept free of graffiti. Work was also done on the windows and doors of the lower levels to prevent any further deterioration of the structure.
At around a 10 degree angle The Tower of Pisa is 60 meters tall and leans at a 10 degree inclination till 1990. Despite being meant to be exactly vertical, it began to tilt during construction. The cause was found to be soft soil under the foundation of the building which allowed it to dip slightly in one direction.
Towers are designed with stability in mind so that people can walk up its sides without fear of falling. Because of this, they are usually built fairly heavy so that they will not sway in the wind or under the weight of many people walking up its side. The Tower of Pisa used stone instead. It was built of marble from France and Germany, and its weight was estimated to be between 70,000 and 80,000 tons.
The tower went through several renovations over the years but did not change its design significantly. It collapsed in February 2013 due to severe weather conditions that led to the abandonment of its renovation project.
From 1999 to 2001, restoration efforts stabilized the tower. Engineers installed weights on the north end of the building while simultaneously removing earth from below, causing it to progressively sink back in that direction. The Leaning Tower of Pisa still leans south, although at just 3.99 degrees. Engineers plan to continue the process of stabilizing the tower for many years to come.
In conclusion, engineers use different methods to stabilize a structure that is leaning toward one side. They can cut holes in the foundation near the leaning wall and pour in grout or concrete to hold the wall in place. They can also build walls around the structure where necessary. Finally, they can move parts of the foundation or even the whole thing.
Some examples of structures that have been stabilized by engineers include: the Eiffel Tower in Paris, the World Trade Center in New York City, and the Statue of Liberty-Ellis Island National Monument.
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 west of north.
The tower was built between 1172 and 1250 as an entrance pavilion to the cathedral. It was designed by Bonnano Pisano, who also designed the famous Fontana dei Quattro Fiumi in Piazza del Duomo. The tower is made of limestone but looks like marble from a distance due to its golden color.
In 2012, scientists conducted ultrasonic tests inside the tower and concluded that it does in fact lean slightly toward the northwest corner. Over time, the base of the tower has been crumbling causing the center of mass to shift farther back toward the front door. The researchers estimated that if maintenance had not been done, the tower would have collapsed entirely in just 40 years.
There are several other buildings in Piazza del Duomo that are leaning at different angles due to construction errors. Some engineers believe that if the leaning structures were not there, the tower might be able to hold its position for another 100 years or more.