The historical symbol of the grandiose construction mistake, the falling tower in Pisa, has a unique property. For 850 years of existence, she has suffered four large and countless small earthquakes, but still stands still. The answer to the question “Why?” Was sought by an international group of 16 engineers and historians of architecture.
When the second floor of the tower was built in 1178, its creators already realized that they were mistaken. A weak foundation and soft ground gave the deviation of the axis of the structure from the vertical by 5 degrees, but then it was considered unimportant. The foundation was strengthened and continued to be built with interruptions for another 200 years. Today, at a height of 56 m, the top of the tower is deviated from the vertical by 5 m and up to the restoration work in 2008 it “fell” by 1 mm per year. But for half a millennium, she did not fall.
The researchers collected information on a wide range of parameters: seismic activity, structural features of the structure, geotechnical data, soil and groundwater composition. And they came to the conclusion that the Leaning Tower of Pisa is indeed a miracle of the world. A unique combination of factors that could hardly be realized on purpose.
The soft ground that caused the tower to tilt initially is so different from the rigid frame of the stone tower that they do not interact with each other. And when the earth's crust shakes, vibrations through the soft earth to the tower are almost not transmitted, so there is no resonance in it. And since already at the beginning of construction to fix the error, the construction was strengthened in every way, then the small loads are practically not terrible.js.src = “&version=v2.8”; 'script', 'facebook-jssdk'));