Leaning Tower of Pisa by noidarocker

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									Leaning Tower of Pisa Now Safe, Repairs Completed



The Iconic Pisa Bell Tower returns to 18th-century angle. For first time in its history, the tower is not
falling over, and is now safe for 300 years.



Leaning Tower of Pisa No Longer in Danger

CORRIERE DELLA SERA.it

Marco Gasperetti

giovedì 29 maggio 2008



Iconic bell tower returns to 18th-century angle. For the first time in its history, the tower is not falling
over. Expert in charge of operation says tower now safe for 300 years.

PISA – January was cold and dangerous in 1990 when the Leaning Tower of Pisa was closed because of
structural risks. Eighteen years later, the newly restored monument celebrates its coming of age with
some excellent news. For the first time since the 18th century, the Tower of Pisa is leaning, but no
longer falling over.

Of course, Bonanno Pisano’s bell tower still leans. If you see it from Via Santa Maria or from the gardens
in Piazza dei Miracoli, it’s still the same odd-looking, immortal monument and uniquely elegant example
of Pisan Romanesque architecture.

The news is that now, after 18 years of closures, interventions and projects verging on science fiction,
the tower’s inclination and the counter weights have stabilised.

The risk is over. No longer is the tower falling down, as was until 1993 when it reached its maximum
overhang of 4.47 metres, or inching back up as it had been until today, thanks to the ministrations of
engineers, technicians and scientists led by Michele Jamiolkowski, an emeritus professor from Turin
Polytechnic.

The latest measurements from sensors under the grass in Piazza dei Miracoli and in the tower’s seven
orders of columns are unequivocal: the overhang has stopped at 3.99 metres. “All the most optimistic
forecasts have been confirmed”, says Professor Jamiolkowski. “We can now say that the Leaning Tower
is safe for at least 300 years”. But there is more good news.

For the first time in 73 years, the tower will reveal a secret that Pisans and tourists had forgotten all
about. In two or perhaps three months’ time, you will be able to enter through the small door and look
up at the sky through the belly of the tower and all seven of its loggias. It is a spectacle that until 1935
had entranced those privileged to see it, including – so they say – Pisa-born Galileo Galilei.

The magic of the view is best savoured on moonless nights when the stars shine brighter. Looking at the
heavens from the bottom of the tower is stargazing through an enormous telescope.

“Until today, the view was obstructed by a floor on which were mounted various devices to gauge the
monument’s stability”, explains Nunziante Squeglia, an engineer and teacher at the University of Pisa,
“but now the floor and scaffolding have been removed.

The view is the same as it used to be”. With its “great celestial eye” restored, the tower will also get a
makeover for over the years, weather and pollution have blackened the marble on the exterior. This,
too, is a delicate operation because the capitals of the seven loggias and the belfry are the tower’s
exquisitely carved white marble “Sunday best”.

Yesterday, stage two of the makeover got under way with a team of experts led by Gisella Capponi from
the central institute for restoration. “We built cantilever scaffolding for the external restoration work”,
explains Giuseppe Bentivoglio, the engineer who is also technical director of the Opera del Duomo, the
body that supervises the monuments in Piazza dei Miracoli. “The scaffolding was built with special
aluminium alloys, similar to those used for racing bicycles, to avoid damage to the structures. This will
ensure an excellent job on the capitals, arches and colonnades”. Work will take three months and the
inauguration is scheduled for late summer.




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The Leaning Tower of Pisa (Italia: Torre pendente di Pisa) or simply The Tower of Pisa (La Torre di Pisa) is
the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa. It is situated behind
the Cathedral and it is the third structure by time in Pisa's Piazza del Duomo (Cathedral Square).



Although intended to stand vertically, the tower began leaning to the southeast soon after the onset of
construction in 1173 due to a poorly laid foundation and loose substrate that has allowed the
foundation to shift direction.



The height of the tower is 55.86 m (183.27 ft) from the ground on the lowest side and 56.70 m (186.02
ft) on the highest side. The width of the walls at the base is 4.09 m (13.42 ft) and at the top 2.48 m (8.14
ft). Its weight is estimated at 14,500 tonnes. The tower has 296 steps (the seventh floor has a different
number of steps on the two sides, if you climb it on the north part you can count only 294 steps). The
tower leans at an angle of 3.97 degrees. This means that the top of the tower is 3.9 meters from where
it would stand if the tower were perfectly vertical.



Due to the peculiarity of the tower, there is no lift inside, on the contrary of common belief.




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PISA




Pisa, located in western Tuscany, is known throughout the world for its famous Leaning Tower, but there
is so much more to Pisa than just this striking landmark. The ecclesiastical city of Pisa began life as a
seaside settlement around 3,000 years ago and was first laid out in the mid-eleventh century. Pisa is
crammed full of wonderful, historical monuments and buildings dating back many hundreds of years and
much of Pisa has retained its medieval appearance. Pisa is also known for its excellent university, which
was established in 1343 and has become one of Italy's top schools. There are a couple of tourism and
tourist information offices in and around the city centre of Pisa and these provide the latest information
about Pisa tourist attractions, museums, events, Pisa festivals, Pisa travel, Pisa sightseeing and general
Pisa tourism and tourist information.



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The Leaning tower of Pisa (Italian: Torre pendente di Pisa) (1360) — freestanding bell tower (campanile),
part of ensemble of city cathedral Santa Maria Majore in Italian city Pisa, became famous since it is not
vertical but leaning. Tower “falls”. The height of the tower is 55.86 m from the ground on lowest side
and 56.70 m on the highest side. The width of the walls at the base is 4.09m and at the top 2.48m. Its
weight is estimated at 14700 tonnes. The tower leans at an angle of 5.5 degrees (deflection of
approximately 4.5 m from vertical). The tower has 294 steps. Construction: Construction of the tower
was carried out in three stages. Starting from August 9, 1173 and with two lengthy interruptions, the
construction work continued for almost 200 yrs till 1360. Tower is considered as bell tower of catholic
cathedral Campo dei Miracoli (Cathedral Square). There has been controversy about the real identity of
the architect of the Leaning Tower of Pisa. Undoubtedly, tower is one of the wonderful bells of Europe.
Earlier, it was considered that the leaning of tower was part of the design but now that version is
refuted. The tower was designed to be “vertical” but as the construction of the tower progressed, the
tower began to sink and thus the “tilt” appeared. Right from 1173 till date, the tower is an object of rapt
attention owing to its leaning and as well as to its original architecture. Constantly measures are being
taken to make the tower more stable. For example, damaged pillars were replaced time and again.
Currently, tower is undergoing gradual underground works to strengthen the foundation. Doors of the
tower were again reopened for the tourists on December 15, 2001. Experiments of Galileo Galilei: A
legend prevails that Galileo Galilei has carried out experiments to demonstrate that the acceleration of a
freely falling object is independent of its mass. He dropped objects of different masses from the top of
Leaning Tower of Pisa and later on described the fall of objects. Evidently, in reality, Galilei had carried
out similar experiments but most probably, the experiments did not have any connection with the tower
in Pisa. World heritage UNESCO, Object № 395 On December 30, 1986, UNESCO conferred World
Heritage status to architectural ensemble (cathedral (Piazza del Duomo), baptistery, bell tower (Leaning
Tower of Pisa) and cemetery). Architecture of ensemble had a significant influence on monumental art
of Italy XI—XIV hundred years.




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The Leaning Tower of Pisa (Italian: Torre pendente di Pisa) or simply The Tower of Pisa (La
Torre di Pisa) is the campanile, or freestanding bell tower, of the cathedral of the Italian city of
Pisa. It is situated behind the cathedral and is the third oldest structure in Pisa's Piazza del
Duomo (Cathedral Square) after the cathedral and the baptistry.

Although intended to stand vertically, the tower began leaning to the southeast soon after the
onset of construction in 1173 due to a poorly laid foundation and loose substrate that has allowed
the foundation to shift direction. The tower presently leans to the southwest.

The height of the tower is 55.86 m (183.27 ft) from the ground on the lowest side and 56.70 m
(186.02 ft) on the highest side. The width of the walls at the base is 4.09 m (13.42 ft) and at the
top 2.48 m (8.14 ft). Its weight is estimated at 14,500 metric tons (16,000 short tons). The tower
has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. The
tower leans at an angle of 3.97 degrees.[1] This means that the top of the tower is 3.9 metres
(12 ft 10 in) from where it would stand if the tower were perfectly vertical.[2]
Construction
The Tower of Pisa was a work of art, performed in three stages over a period of about 177 years.
Construction of the first floor of the white marble campanile began on August 9, 1173, a period
of military success and prosperity. This first floor is surrounded by pillars with classical capitals,
leaning against blind arches.

The tower began to sink after construction progressed to the third floor in 1178. This was due to
a mere three-meter foundation, set in weak, unstable subsoil. This means the design was flawed
from the beginning. Construction was subsequently halted for almost a century, because the
Pisans were almost continually engaged in battles with Genoa, Lucca and Florence. This allowed
time for the underlying soil to settle. Otherwise, the tower would almost certainly have toppled.
In 1198, clocks were temporarily installed on the third floor of the unfinished construction.

In 1272, construction resumed under Giovanni di Simone, architect of the Camposanto. In an
effort to compensate for the tilt, the engineers built higher floors with one side taller than the
other. This made the tower begin to lean in the other direction. Because of this, the tower is
actually curved.[3] Construction was halted again in 1284, when the Pisans were defeated by the
Genoans in the Battle of Meloria.

The seventh floor was completed in 1319. The bell-chamber was not finally added until 1372. It
was built by Tommaso di Andrea Pisano, who succeeded in harmonizing the Gothic elements of
the bell-chamber with the Romanesque style of the tower. There are seven bells, one for each
note of the musical scale. The largest one was installed in 1655.

After a phase (1990-2001) of structural strengthening, the tower is currently undergoing gradual
surface restoration, in order to repair visual damage, mostly corrosion and blackening. These are
particularly strong due to the tower's age and to its particular conditions with respect to wind and
rain



Timeline

      On 5 January 1172, Donna Berta di Bernardo, a widow and resident of the house of dell'Opera di
       Santa Maria, bequeathed sessanta soldi or "sixty coins" to the Opera Campanilis petrarum
       Sancte Marie. This money was to be used toward the purchase of a few stones which still form
       the base of the bell tower today.[5]
      On 9 August 1173, the foundations of the Tower were laid.[6]
      Nearly four centuries later Giorgio Vasari wrote : "Guglielmo, according to what is being said, in
       [this] year 1174 with Bonanno as sculptor, laid the foundations of the belltower of the cathedral
       in Pisa."
      Another possible builder is Gerardo di Gerardo. His name appears as a witness to the above
       legacy of Berta di Bernardo as "Master Gerardo", and as a worker whose name was Gerardo.
      A more probable builder is Diotisalvi, because of the construction period and the structure's
       affinities with other buildings in Pisa. But he usually signed his works, and there is no signature
       by him in the belltower.
      Giovanni di Simone was heavily involved in the work of completing the tower, under the
       direction of Giovanni Pisano, who at the time was master builder of the Opera di Santa Maria
       Maggiore. He could be the same Giovanni Pisano who completed the belfry tower.
      Giorgio Vasari indicates that Tommaso di Andrea Pisano was the designer of the belfry between
       1360 and 1370.
      On 27 December 1233 the worker Benenato, son of Gerardo Bottici, oversaw the continuation
       of the construction of the belltower.[7]
      On 23 February 1260 Guido Speziale, son of Giovanni, a worker on the cathedral Santa Maria
       Maggiore, was elected to oversee the building of the Tower.[8]
      On 12 April 1264 the master builder Giovanni di Simone and 23 workers went to the mountains
       close to Pisa to cut marble. The cut stones were given to Rainaldo Speziale, worker of St.
       Francesco.[9]


The architect
There has been controversy about the real identity of the architect of the Leaning Tower of Pisa.
For many years, the design was attributed to Guglielmo and Bonanno Pisano [10], a well-known
12th-century resident artist of Pisa, famous for his bronze casting, particularly in the Pisa
Duomo. Bonanno Pisano left Pisa in 1185 for Monreale, Sicily, only to come back and die in his
home town. His sarcophagus was discovered at the foot of the tower in 1820. However recent
studies[11] seem to indicate Diotisalvi as the original architect due to the time of construction and
affinity with other Diotisalvi works, notably the bell tower of San Nicola (Pisa) and the
Baptistery in Pisa. However, he usually signed his works and there is no signature by him in the
bell tower which leads to further speculation.

History following construction
Galileo Galilei is said to have dropped two cannon balls of different masses from the tower to
demonstrate that their descending speed was independent of their mass. This is considered an
apocryphal tale, and the only source for it comes from Galileo's secretary.[12]

During World War II, the Allies discovered that the Nazis were using it as an observation post. A
U.S. Army sergeant was briefly entrusted with the fate of the tower and his decision not to call in
an artillery strike saved the tower from destruction.[13]

On February 27, 1964, the government of Italy requested aid in preventing the tower from
toppling. It was, however, considered important to retain the current tilt, due to the vital role that
this element played in promoting the tourism industry of Pisa. [14] A multinational task force of
engineers, mathematicians and historians was assigned and met on the Azores islands to discuss
stabilization methods. It was found that the tilt was increasing in combination with the softer
foundations on the lower side. Many methods were proposed to stabilize the tower, including the
addition of 800 metric tons of lead counterweights to the raised end of the base.[15]
In 1987, the tower was declared as part of the Piazza dei Miracoli UNESCO World Heritage Site
along with the neighbouring cathedral, baptistery and cemetery.

On 7 January 1990, after over two decades of work on the subject, the tower was closed to the
public. While the tower was closed, the bells were removed to relieve some weight, and cables
were cinched around the third level and anchored several hundred meters away. Apartments and
houses in the path of the tower were vacated for safety. The final solution to prevent the collapse
of the tower was to slightly straighten the tower to a safer angle, by removing 38 cubic metres
(50 cu yd) of soil from underneath the raised end. The tower was straightened by 18 inches (45
centimetres), returning to the exact position that it occupied in 1838. After a decade of corrective
reconstruction and stabilization efforts, the tower was reopened to the public on December 15,
2001, and has been declared stable for at least another 300 years.[15]

In May 2008, after the removal of another 70 metric tons (77 short tons) of earth, engineers
announced that the Tower had been stabilized such that it had stopped moving for the first time
in its history. They stated it would be stable for at least 200 years.[16]

Technical information




View looking up

      Elevation of Piazza dei Miracoli: about 2 metres (6 feet, DMS)
      Height: 55.863 metres (183 ft 3 in), 8 stories
      Outer diameter of base: 15.484 metres (50 ft 9.6 in)
      Inner diameter of base: 7.368 metres (24 ft 2.1 in)
      Angle of slant: 3.97 degrees[17] or 3.9 m (12 ft 10 in) from the vertical[18]
      Weight: 14,700 metric tons (16,200 short tons)
      Thickness of walls at the base: 8 ft (2.4 m)
      Total number of bells: 7, tuned to musical scale, clockwise
           o 1st bell: L'assunta, cast in 1654 by Giovanni Pietro Orlandi, weight 3,620 kg (7,981 lb)
           o 2nd bell: Il Crocifisso, cast in 1572 by Vincenzo Possenti, weight 2,462 kg (5,428 lb)
           o 3rd bell: San Ranieri, cast in 1719-1721 by Giovanni Andrea Moreni, weight 1,448 kg
               (3,192 lb)
           o 4th bell: La Terza (1st small one), cast in 1473, weight 300 kg (661 lb)
           o 5th bell: La Pasquereccia or La Giustizia, cast in 1262 by Lotteringo, weight 1,014 kg
               (2,235 lb)
           o 6th bell: Il Vespruccio (2nd small one), cast in the 14th century and again in 1501 by
               Nicola di Jacopo, weight 1,000 kg (2,205 lb)
                                                                                            [19]
           o 7th bell: Dal Pozzo, cast in 1606 and again in 2004, weight 652 kg (1,437 lb)
                                [20]
      Steps to bell tower: 296

A special note on the 5th bell: The name Pasquareccia comes from Easter, because it used to
ring on Easter day. However, this bell is older than the bell-chamber itself, and comes from the
tower Vergata in Palazzo Pretorio in Pisa, where it was called La Giustizia (The Justice). The
bell was tolled to announce capital executions of criminals and traitors, including Count Ugolino
in 1289 [21] A new bell was transferred on the belltower to replace the broken Pasquareccia bell
at the end of the 18th century.



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The Leaning Tower of Pisa

  By Dominic Siano

  Regarded widely as one of the greatest wonders of the
  world, the Leaning Tower of Pisa is situated in the
  city of Pisa, Italy. Italy has an important place in the
  history of the world, and the Leaning Tower of Pisa
  just adds more to the country's rich history. The
  Leaning Tower of Pisa was originally built as a marble
  campanile, or bell tower, for Pisa's cathedral, located in
  the 'Campo dei Miracoli'.

  The Tower was given such a name because it does not stand erect like other towers, but
  'leans' at an angle of 5.5 degrees from the perpendicular. This is because the uneven settling
  of its foundation.The height of the Leaning Tower of Pisa is 55 meters from the ground
  while its weight is estimated at 14,453 tons. The Leaning Tower of Pisa has 296 steps.
The history of the Leaning Tower of Pisa is interesting as well. It took centuries to
construct the Leaning Tower of Pisa. The construction began on August 9, 1173, and went
on for two centuries. The third floor of the Leaning Tower of Pisa was constructed in 1178
when it began to lean, and thereafter the construction stopped. Four more floors were
constructed in 1272 to make-up for the inclination. The construction stopped again until
1372 when the last floor of the Leaning Tower of Pisa was built. In the same year, the bell
was finally installed.

The Leaning Tower of Pisa holds a significant place in the world history as well. Famous
physician Galileo Galilei once dropped two cannon balls of different masses from the
Leaning Tower of Pisa to demonstrate their speed of descent was independent of their mass.
After some years, Italian dictator Benito Mussolini commanded the Tower to be erected. So
cement was poured into its foundation but the consequences were disappointing as the
Leaning Tower of Pisa sank further into the soft soil. Reflecting more on the history of the
Leaning Tower of Pisa, it would be interesting to know that during World War II, the
American forces were ordered to demolish all the towers in the city of Pisa because of the
threat of snipers in the city. All the towers were demolished except the Leaning Tower of
Pisa because of a last-minute order to retreat.

In 1990, the Leaning Tower of Pisa was closed as there was a threat of collapse. This was
because it was subsiding at the rate of 0.03 inches a year. Engineers undertook a
strengthening project that decreased the lean by 17 inches to about 13.5 ft. The work was
completed in May 2001 and reopened for public in June 16, 2001.

The Leaning Tower of Pisa may be leaning because of a blunder committed by 12th century
engineers, but it is still one of the most famous structures known across the world and will
always remains so.

								
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