Famous for its unintended tilt, the 56m tower took nearly 200 years to build - work started in 1173. Five years later it started tilting. The tilt was noticeable as workers built the second floor. The shift was caused by shallow foundations of 3m and unstable subsoil.
The leaning tower of Pisa started leaning due to the uneven settling of its foundations in the soft ground. The tower's construction began in 1173 and by the time three of its eight stories were completed, the uneven settling became noticeable. At that time, war broke out between Italian city-states and construction was halted for almost a century. This pause in construction allowed the tower's foundation to settle further, which likely prevented its early collapse.
The foundation of a building is the base on which the entire structure is built. It needs to be strong and stable to support the weight of the building above it. In the case of the leaning tower of Pisa, the ground beneath the foundation was soft, causing uneven settling. This means that different parts of the foundation sank or shifted more than others, leading to the tower leaning to one side.
The soft ground in Pisa is made up of clay, silt, and sand, which can compress under the weight of the building. When the tower was being constructed, the weight of the building caused the ground to compress unevenly, leading to the tower leaning. The builders may not have been aware of the extent of the softness of the ground during the construction process, which contributed to the problem.
The pause in construction due to the war allowed the tower's foundation to settle further, which likely helped to stabilize the leaning. If construction had continued without this pause, the tower may have collapsed. The leaning tower of Pisa has become iconic and attracts visitors from around the world, but it serves as a reminder of the importance of strong and stable foundations in construction to avoid structural issues like leaning.
The leaning of the Tower of Pisa can be attributed to a combination of factors, with the primary one being the poor foundation. The tower was constructed on soft, unstable soil composed of clay, fine sand, and shells. This type of soil is prone to shifting and settling, which caused the tower to start leaning.
When construction began on the tower in 1173, the builders noticed that the tower was already leaning slightly during the construction of the third floor. This was due to the uneven settling of the foundation. The weight of the tower was unevenly distributed, causing it to tilt towards the weaker side.
Furthermore, the construction of the tower was halted multiple times due to wars and political conflicts. These interruptions in construction allowed time for the soil to settle further, which may have prevented the tower from collapsing entirely. If the tower had been completed without these breaks, it is likely that it would have fallen over.
To address the lean, efforts were made to counterbalance the tilt by constructing additional floors that were slightly taller on the lower side of the tower. However, these attempts were not entirely successful in stopping the lean, and the tower continued to lean.
In modern times, extensive restoration and stabilization efforts have been undertaken to prevent the tower from further tilting or collapsing. These efforts involved techniques such as removing soil from the higher side, installing counterweights, and using steel cables to secure the tower to the ground.
Overall, the leaning of the Tower of Pisa can be attributed to the combination of a weak foundation on unstable soil and the interruptions in construction, which allowed the soil to settle unevenly.