![]() ![]() While digging, Burland says they found the remnants of a concrete foundation that had been built in 1828 they attached the tower to it with massive chains, creating even stronger footing. The reparations raised the base on the north side by four meters and lifted the entire tower along with it. When the project ended in 2001 the slope has been reduced to just under five degrees, leaving the tower about 13 feet from the perpendicular.īurland’s team painstakingly extracted about 20 liters of soil at a time from under the south side of the base and steadily installed a system of tunnels and wells to drain the water that was keeping the soil wet, causing the base to sink. At that time the north side of the tower’s base had sunk, leading to a 5.5-degree slope toward the north of the 187-foot, 14,700-metric-ton structure. “The height and weight coupled with the porous soil meant it should have fallen centuries ago.” Although today he still cannot explain for sure why it still stands, he is certain it would not have lasted much longer if the commission had not intervened. “No matter how many calculations we made, the tower should not have been standing at all,” Burland told Scientific American. The top-heavy bell tower, built in 1173 on spongy ground, seemed to defy the laws of physics. Back in 1989 the soil-mechanics expert had been approached to lead a 13-member commission to save the structure from collapsing. ![]() The news came to John Burland, an emeritus professor at Imperial College in London, by way of a 4 A.M. Although that may seem small, it is a welcome gift after centuries of worry that the building would simply topple. The surprise gain straightened the landmark by four centimeters. Last week they announced that the tower had been self-correcting for more than a decade and had finally stopped. Once every year, engineers measure the Leaning Tower of Pisa’s precarious tilt. ![]()
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