lean gives leaning Tower of Pisa new lease on life
The first period of construction began in 1173 and lasted five years. A century later, during an equally brief bout of construction activity, the tower started to lean to the south and masons began to build a backward curve into the stonework in an effort to keep it vertical. Another century passed before a final decade of construction completed the belfry in 1370, when the lean was approximately 3.5 degrees from the vertical.
The 142-tonne Pisa tower itself was likely on the verge of collapse. The tower had a negligible factor of safety against toppling and was leaning more each year. Built on 5 m of silty soil over alternating layers of clay and sand, the tower would probably have collapsed during construction.
Did they manage to arrest further leaning of the tower?
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