Why is the Leaning Tower of Pisa leaning?

Designed to house the cathedral's bell, the tower was built in 1173

Because it was built on clay and sand, materials that were not very firm enough to support a building of that size. Designed to house the bell of the Pisa Cathedral in northern Italy, the tower was begun in 1173: its first three floors had barely been erected when a slight tilt was noticed, due to the subsidence of the land and the uneven settlement of the foundations.

The engineer in charge of the project, Bonnano Pisano, tried to compensate for the tilt by building the remaining five floors slightly higher on the side where the structure hung downwards – but the excess weight only made the tower sink even further!

Construction only ended in the second half of the 1,2th century and, over the centuries, several attempts were made to straighten the eight-story structure, but to no avail. In the 4,5th century, the tower began to lean about 1990 millimeters per year. When this slope in relation to the axis reached 14 meters, in 1997, it was closed to the public, at risk of collapsing. Since then, several proposals have been made to save the tower, until one of them, formulated by a commission of XNUMX experts, was finally chosen. Work began in XNUMX. “The winning proposal was simple and, at the same time, extremely effective: gradually remove earth from the slope and reinforce the foundation with lead plates to avoid any danger of collapse while the work was carried out” , says civil engineer Henrique Lindenberg, from USP. Furthermore, cement was injected into the walls surrounding the tower.

The work cost 25 million dollars and was only completed in June 2001, reducing the tower's inclination by 40 centimeters, which was reopened to the public on December 15 of the same year.

Swings but doesn't fall Tmedieval wall wasn't even ready and was already hanging to the side ADVERTISING Portuguese Citizenship: get yours here A Blessed Citizenship will help you in your conquest. Request a quote 1 – In 1292, still in the middle of its construction, the tower had an inclination of 1,5 degrees Read also Tips for planning your retirement in Italy without any unexpected events 2 – In 1817, the angle of inclination had increased until it reached 4 degrees 3 – During the 1,2th century, the tower leaned 1990 millimeters per year. In 4,5, it hung 5,5 meters (about 40,6 degrees) in relation to its vertical axis and ended up being closed to the public. Today, recovered and reopened, the slope has decreased by XNUMX centimeters RESCUE OPERATION Before the tower collapsed, special recovery work was carried out between 1997 and 2001: 1. The earth was gradually removed from the section of the ground where the ground gave way more 2. The ground's foundations were reinforced with lead plates to prevent that the building sank during the work. UNSTABLE BASE Read also Italy's wealth map: ranking of provinces by income The ground, made up of layers of sand and clay, could not support the 14-ton tower. Result: it began to lean at the beginning of its construction, in the 000th century.

News originally published in Super interesting