Ten-year renovation 43 cm
The leaning tower of Pisa took nearly 200 years to build, and it was unlucky from the beginning. When it was built to 9 meters high, it began to tilt. Rescue and construction started almost at the same time, and several stops were made to repair. Now, the value of the leaning tower is getting higher and higher, and the task of saving it is becoming more and more urgent.
In 1980s, it was predicted that the Leaning Tower of Pisa would collapse in 2003-2004! Time is the most terrible enemy of the Leaning Tower of Pisa. It is like a patient with congenital deficiency, aging steadily year after year, succumbing to the gravity of the earth, as if unable to stand up unintentionally. The whole audience was in an uproar and the rescue Committee was at a loss. There are many ways to save the world, but we dare not try it easily, otherwise it will lead to irreparable losses.
1934 What happened is a lesson. At that time, in order to "rectify the deviation", cement was injected into the hypotenuse of the tower foundation. Unexpectedly, this not only did not help ease the tilt, but made it tilt 6 mm more in one year.
After 1990, the recovery work has kept a low profile. In fact, what method to adopt is controversial and the work pressure is great. Professor Piero Pierotti from the University of Pisa and Professor James Baker from the History Department of Columbia University strongly oppose some restoration plans. They say? Quot irresponsible and absurd behavior. "
"Pisa is full of criticism," Baker said. "From 1990 to 1998,150,000 dollars was spent on some so-called temporary measures, but this actually only brought more damage."
Pierrot Ti, who has worked in the history department of Pisa University for more than 40 years, expressed dissatisfaction with the extreme blockade of information about the restoration of the leaning tower. Recently, he published a book, which collected all kinds of strange restoration methods contributed by people all over the world in the past 50 years.
It is suggested that the leaning tower should be divided into blocks and reassembled after the foundation is compacted. A proposal suggests drilling 10 thousand small holes in the tower to reduce the weight; China engineers and technicians suggested that another leaning tower inclined in the opposite direction should be built next to the leaning tower to support the original leaning tower. Some people say that a transparent cover can be built to cover the leaning tower of Pisa; Others advocate hanging a helium balloon on the top of the leaning tower and sticking it on the top floor. At the same time, the grass around the leaning tower is built into a slope, which is consistent with the inclination direction of the bell tower, so that the leaning tower looks upright. This method will make millions of tourists get neck cramps under the leaning tower of Pisa every year.
At present, the "soil stabilization" method of "righting" the leaning tower of Pisa was invented by Dr. Fernando Lizzie, an engineer in Naples, Italy. This method is famous for using a large number of "small thin tubes" in the construction process. The main measure of the rectification project is to slowly extract the soil under the foundation on the north side of the south leaning tower foundation. Dr. Lizzie's invention has been widely used in the rectification of many ancient buildings all over the world and performed well: Winchester Castle, England, Lamberhurst Church in Santa Maria Novella; Memorial Avenue Bridge in Dublin, Ireland and Three Arch Bridges in Venice, Italy.
When the Leaning Tower of Pisa was calibrated to 65,438+0/2 degrees, Dr. Lizzie was very worried that the Leaning Tower Rescue Committee would stop working and had little effect. Perhaps he knows better than others that the leaning tower is very vulnerable to the further loosening and collapse of soil, and the possible external dangers are also worrying. Once an earthquake happens, the leaning tower seems to have no resistance. On June 23, 2000, Dr. Lizzie wrote to the Italian Minister of Public Affairs, expressing his concerns bluntly.
The Italian government has issued relevant laws, authorizations and presidential decrees for the Leaning Tower of Pisa. The composition, term of office, functions, powers and responsibilities of the Leaning Tower of Pisa Rescue Committee are specified in detail. The Committee consists of 13 experienced experts at home and abroad, including two scholars who study medieval art and history.
The leaning tower rectification project cost 25 million dollars. 1998, for the sake of safety, the workers fixed the leaning tower of Pisa with huge steel cables, and the whole Italian media almost laughed in unison: "Ugly pants suspenders." However, 1 years later, the project has shown great achievements. After the project is completed, the leaning tower of Pisa will be 43cm less than that of 1700, which can maintain sufficient stability. But the naked eye can't find the deviation of 43 cm, and the beauty of the leaning tower of Pisa remains the same.
Someone asked: why not completely correct the deviation of the leaning tower and make it completely upright? There are both technical difficulties and other considerations: "If the leaning tower of Pisa is not tilted, Pisa is not Pisa". "Tilt" is its identification. From the type analysis of its decoration and architectural style, as well as the few documents left in the process of many revisions, we can know that the leaning tower of Pisa condenses the wisdom and hard work of many people beyond imagination.
How does the leaning tower of Pisa lean?
Boda, a widow from Bernardo, has been living in the charity hall of the Virgin Mary. 117265438+1October 5, when she died, she left a message and presented 60 silver coins to buy marble to build the musical bell tower of the Virgin Mary.
After more than a year of planning, the project finally broke ground on August 9, 1 173. With the progress of basic engineering, countless boulders were transported to the construction site near the church. According to the design, the bell tower is an eight-story cylindrical building, all made of white marble, which is a model of Roman architecture.
The sun shines on the city of Pisa in central Italy.
"Look! This bell tower is inclined! "
"Oh, is it going to collapse? Stay away, it's too dangerous! "
When the bell tower was built on the third floor, it just reached 1.5 meters, and the tower body appeared terrible inclination. Not only the worried designers and builders found it, but also people in Liancheng began to talk about the crooked unfinished bell tower. B Pisano, the engineer in charge, came up with a way to increase the height of the concave edge. Unexpectedly, this not only didn't help, but made the tower sink even more. 1 178, the project came to a standstill.
The specific reasons for the tilt are not clear, but at least two things are certain: first, the building is overweight; Second, the settlement height of the bottom soil is different.
Since then, the two restarts have started with the determination to correct the deviation. For the first time, Diovanni Ti Simon was in charge, but the degree of inclination did not change; The second time, from 1272, four floors were built in three years, with a total of seven floors. At this time, Diovanni Pisano, the son of the late "rectification" master Diovanni Disimone, continued to work, and another engineer Guido followed in his father's footsteps, which was very tragic. Since then, the project has stopped again. The top bell tower was not built until 1360. 1370, the project was finally completed.
From the beginning of construction to the final completion, the construction of this bell tower took nearly 200 years. During the construction process, with the lessons of daily inclination and "rectification", it is still worrying after the construction is completed.
Who designed the Leaning Tower of Pisa? What is the reason why the tower keeps tilting?
The experts argued endlessly about the first question. Some people say that it is a bronze foundry with excellent technology, Bernano; Some people say that this is the work of Dior Tisavi, the most famous architect in the 12th century. Maybe Gerald's meritorious service. He is more like a collaborator and interpreter of Otisavi than just carrying out the instructions of the master architect. Or Gudrato who built the Notre Dame Opera House? Then there was 1 160, the German Gugleyo who presided over the original pulpit of Pisa Cathedral. Who started it is still a mystery. But what is certain is that11August 9, 73 is the birthday of the leaning tower of Pisa.
There are three theories about why the leaning tower of Pisa leans. One is because the construction process is not accurate enough, which deviates from the original design scheme; Another view is that the design itself; After entering the 20th century, the "foundation theory" gradually gained the upper hand, thinking that the foundation mainly composed of sand and clay could not bear the weight of the whole tower 14000 tons before it tilted. Now, this statement has been gradually accepted by people.
Through the whole story, we may find the eternal "genetic code" of the leaning tower of Pisa: the constant interaction between the leaning tower and the land under its feet; Perhaps, we can also find some human qualities worth preserving: refusing to compromise.