Why does the Tower of Pisa lean?

The Tower of Pisa began to tilt in 1173 when construction began. The soil was mostly composed of clay, fine sand and shells (probably because the city is located between the Arno and the Serchio rivers) which defined that the Tower was made on soft ground. The leaning process began when the workers were done with the second floor in 1178. But, soon due to the city of Pisa fighting wars against Genoa, Lucca and Florence the construction took a backseat for almost 100 years. Many modern analyses say that this break acted to be a savior as it gave enough time for the soil to settle. Otherwise, there were enough chances for the Tower to topple down.

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The tower was leaning 0.2 degrees north of vertical when the construction resumed again. But by the time the builders reached the seventh floor, the tower leaned one degree south.  Again, for unknown reasons the construction was halted. There were many efforts given by the engineers and architects from all over the world to track and monitor the lean. These attempts involved- adding plaster to the foundation stonework, wrapping plastic-coated steel pieces around the tower up to the second floor, pouring a concrete ring around the base of the tower, laying lead counterweights to the north side, installing anchored cable counterweights, and extracting soil from underneath the north side.

Engineers declared that the tower had stopped leaning for the first time and had stabilized only after the removal of 70 metric tons of soil in 2008.  Its lean is now only about four degrees (prior to the all the restoration attempts, the lean was 5.5 degrees).

Thus, we can say that the Leaning Tower of Pisa won’t fall for at least the next 200 years.

Post Written by -  Adap Immanuel Teron