Cause behind lean of pisa tower

Cause behind lean of pisa tower

The Tower of Pisa leans because its foundation was laid on unstable ground. In addition, the foundation itself was not build deep enough for a building of its size. It began to sink before construction was even completed, and it continues to sink at a very slow rate today.

The Leaning Tower of Pisa

The Leaning Tower of Pisa

The Leaning Tower of Pisa is the famous bell tower, in Italy, that began to lean in the year 1173. It was built to display the wealth of the people of Pisa. The people of Pisa were sailors who had conquered lands such as Jerusalem, Carthago, Ibiza, Mallorca, Africa, Belgium, Britannia, Norway, Spain, and Morocco. Their only real enemies were from the city of Florence. They needed the tower to show the people of Florence how well they were doing.         Architects realized that the tower was leaning when they had finished building one and one half meters of the third floor. The damage was irreversible so they halted construction until 1272 because war broke out against Florence. All of the money was spent on warfare and there was not much left for the tower. The lean was caused by the sandy and marshy soil that the tower was built on. During construction from 1272 till 1275, the tower continued to lean. In 1275 war with Florence broke out again. After this they began to construct the belfry, credit for which is often given to Tommaso, son of Andrea Pisano. The construction was believed to have been completed in 1350. In 1392, causing great humiliation, Pisa was sold to Florence and the residents were forced into slavery. They never managed to gain back the wealth that they had in the early years.

Leaning Tower Fact Sheet

Official Italian Name	Torre Pendente Di Pisa
Function	Bell Tower
Original Architect	Bonanno Pisano
Years of Construction	1173 - 1350
First Bells Added	1198
Height	55.863 meters, 185 feet, 8 stories
Direction of Lean	1173-1250: North and 1273-1999: South
Largest Bell	3.5 tons
Oldest Bell's Name	Pasquarreccia
Address of Tower	Campo Dei Miracoli (The Field of Miracles) in Pisa, Italy
weight	14700 metric tons
Thickness of Walls at Base	8 feet

The History of The Leaning Tower of Pisa

Humans make mistakes, after all, no human is perfect. One mistake made in the 11th century resulted in a 14,500 ton leaning tower. This miscalculation would later become a symbol of civic pride, but tell that to the man who designed it!

The learning tower of Pisa, known as Torre Pendente di Pisa in Italian, is different than most medieval architecture. This particular section won't cover the highly advanced construction techniques that were used, it is important to mention how this tower's design is significant.

The Leaning Tower is the third oldest building on Pisa'sPiazza del Duomo (cathedral square), the Cathedral and Baptistry were first.

Utilizing many columns and archs, this tower represents an advanced understanding of weight and load characteristics, showing the Italian architectures' knowledge.

What the architect didn't account for however, was the base of the tower being built on a dense section of clay.

The Early Years

The construction of the Tower of Pisa began on August 9, 1173. Originally designed to be a bell tower, the tower actually stood upright for over 5 years, but just after the completion of the third floor (1178) it began to lean. The citizens of Italy were shocked as it began to lean ever so slightly.

The foundation of the tower, only 3 meter deep, was built on a dense clay mixture and impacted the soil. As it turned out, the clay was not nearly as strong enough as required to hold the tower upright, and so the weight of the tower began to diffuse downward until it had found the weakest point.

After this, construction halted for 100 years. The government hoped that the soil would settle, giving it enough strength to hold the weight of the tower. As well, the country was focused on its war with Genoa, which was quite brutal and ravaging at the time.

Construction Resumes

The Tower at Night

After the 100 year hiatus, Giovanni di Simone stepped forward in 1272 and began to add four more floors to the tower. He actually managed to cause the tower to lean over more when he tried to compensate for the original lean by making one side of the upper floors taller than the other.

In 1284 construction was halted again, this time because of the Battle of Meloria, in which the Pisans were defeated by the Genoans.

In 1319 the 7th floor was finished. The bell-chamber was added in 1372, and then the tower was left alone until the 19th century.

In 1838 Alessandro Della Gherardesca, an established architect, dug a pathway near the base of the tower so that people could see the intricately crafted base. The tower began to lean even more as a result, likely due to the decreased amount of support available within the soil.

World War Two

This war was brutal and bloody for the entire world, and its effects were felt everywhere from America to rural Africa. In relation to the leaning tower of Pisa, however, it is pure luck.

When the American soldiers invaded, they were ordered to destroy any and all buildings in order to neutralize the thread of enemy snipers. There were no exceptions to this rule, and hundreds of buildings were blown up as the forces steadily advanced over the Italian countryside. The only thing which prevented the leaning tower of Pisa from being destroyed was a retreat that took place shortly after the arrival of the Americans, necessitating no need to destroy the national monument.

Steadier than Ever

The leaden counterweight

In 1964, Italy asked help to prevent the Leaning Tower from toppling. They wanted to keep the lean though, because of its importance for Pisa's tourism. A team of engineers and historians came together on the Azores to discuss the problem. As a temporary measure, a leaden counterweight (800 tonnes) was installed.

In 1987, the Leaning Tower of Pisa was declared a Unesco World Heritage Site, along with the entire Piazza Del Duomo.

In 1990, the Leaning Tower was closed. The bells were removed and the tower was anchored.

Reopened in 2001 for tourists, the leaning tower of Pisa is finally sturdy and safe. Naturally, climbing to the top of the tower has become the most popular tourist activity within reason, and for good reason: with a history as deep and as wrought with unfortunate circumstance as this one, it's hard not to get excited about.

Construction of the Leaning Tower of Pisa

Begun in 1173, the process by which the leaning tower of Pisa had transformed into the monument as we know it today was long and drawn out. In fact, it took over 800 years from start to finish.

Intricate carvings, columns, arch's, and other design elements are incorporated into the construction of the tower. For medieval Europe, these types of design themes and construction processes were way ahead of their time, resulting in a structure that has remained timeless in appearance through the ages.

The tower was built with limestone and lime mortar, though the exterior of the tower is covered in marble. Ironically, the limestone is probably why the tower has not cracked and broken- the rock is flexible enough that it can withstand the pressures placed on it by the lean. It is doubtful that the original architect, Bonanno Pisano, had any idea that the qualities of limestone would play a role in preventing its ultimate collapse.

Originally, the leaning tower of Pisa was to be a bell tower for a cathedral. Five years after the initial construction of two floors it began to lean once the third floor was completed. At the time the cause of the lean was not known, though it was discovered many years later that the lean was the result of the tower being built on a dense clay mixture that was unable to fully support the weight of the tower.

As you can imagine, the construction process was halted for nearly 100 years. The architects of the time hoped that the soul would settle and harden over time, allowing them to resume construction and correct the lean.

Giovanni di Simone, Alessandro Della Gherardesca, and Benito Mussolini

100 long years passed before Giovanni di Simone constructed four additional floors. He had also intended to counteract the lean during the construction process but, like the original architects, made a critical miscalculation. The result was the four floors being built crooked, causing the tower to shift even more.

In 1372 the bell chamber was finally attached to the leaning tower of Pisa, and there were no further modifications or additions made until the 19 th century.

Alessandro Della Gherardesca decided to increase the value of the tower to the tourism industry by digging a pathway around the base of the tower that would allow tourists to see the detail that was put into the base. This took place in 1838, and resulted in the tower leaning even more when Gherardesca's workers struck water, flooding the ditches and increasing the tilt.

Benito Mussolini was the next to try his hand stabilizing the tower in 1934. He felt that the tower was an embarrassment to Italy and that it must be corrected and returned to a perpendicular state. As a result of his orders, 361 holes were drilled into the foundation of the tower and 90 tonnes of cement were used to fill them. The cement, rather than form up in the holes and act as a counterweight, sank into the clay beneath the structure, causing the tower to lean over even more.

End of Construction

The Leaning Tower of Pisa was closed for construction in 1990 and was then reopened once it was safe for everyone to tour. From start to finish, the leaning tower of Pisa took over 800 years to be constructed- probably the longest construction time in the world!

Facts About the Leaning Tower of Pisa

• The leaning tower of Pisa weighs 14,500 tonnes - Although it took quite a long time for construction to be completed, the official estimated weight of the tower is just shy of 14,500 tonnes. No wonder the clay foundation couldn't handle the weight!
• The tower took over 800 years to completely finish - With the final modifications to the tower made in the early 21 st century, the entire process took over 800 years. During this time it witness two great wars, civil war, change in religious governments, and a change in use. It was "completed" in 1350 (over 200 years after its initial construction), but has undergone constant additions and modifications since that date.
• The leaning tower of Pisa is only 55.86 meters tall - With its low height, it's the smallest "tower" achieve worldwide recognition.
• Europe 's most famous monument was the result of a slight miscalculation - Although many factors have contributed to the lean, the decision of where to build the tower resulted in the original tilt of the tower.
• It is a symbol of national pride - What is the first thing that comes to mind when you hear the word Pisa ?
• It is located in the Piazza Dei Miracoli - The "field of miracles" is where the tower is located, along with a few other famous structures, such as the Duomo, the Camposanto, and the Baptistery.
• It was upright for five years upon completion of its initial construction - Having only two floors, no one was aware of any problem with the tower. Upon the addition of the third floor the tower began to lean, and the result was thousands of confused people and hundreds of years of quick-fixes.
• Construction was halted for 100 years - Once the tower began to lean the construction was halted for 100 years. During this time, engineers hopes that the clay beneath the tower would settle and harden enough to permit further construction.
• A new architect resume construction - Giovanni di Simone continued where the tower had left off, adding four additional floors to the tower. Fortunately, and despite his efforts, he was unable to correct the lean.
• A bad idea made the lean worse - Alessandro Della Gherardesca tried to show the world the intricately decorated base of the tower by digging a walkway around the base. You can imagine the resulting disaster when his workers struck water, flooding the ditches.
• Mussolini tried to fix the tower - Embarrassed of the tower, and calling it a disgrace to national pride, he attempted to fix the tower by way of a cement counterweight drilled into the base of the tower. It didn't work.
• The tower has 294 steps - How fast can you make it up?
• The tower was almost torn down - American soldiers, under the orders to destroy all buildings that may act as a potential nest for enemy snipers, nearly destroyed the famous tower during World War Two.