The Famous Garisenda Tower in Bologna Is Too Leaning!

No, it's not in Pisa—an Italian leaning tower is back at it! Instead, it's Bologna's Garisenda Tower, which has been closed off by authorities due to concerns over its collapse, along with the important piazza that sits next to it. These "twin towers," which are only a few meters away from the considerably taller Asinelli Tower (which is twice as tall), are iconic images of the city that have stood the test of time. The Garisenda has been 4 degrees slanted for centuries. However, "traces of unexpected rotation" in the incline have been discovered in recent inspections, prompting an immediate closure for "years."

The mayor of the Italian city, Matteo Lepore, has called for the closure of Piazza di Porta Ravegnana, saying that it is vital to "save" the Garisenda Tower. The edifice is a 48-meter (157.4-foot) medieval construction from the 12th century. "We want to make it safe and restore it; we're not intervening because we think it could collapse at any moment," he stated.

The observation of an extraordinary rise in the tower's swaying by experts from the University of Bologna sparked this topic. The Garisenda tower, which attracted the attention of writers such as Charles Dickens when he visited Bologna, has a 4-degree tilt, which is marginally steeper than the more famous Leaning Tower of Pisa in Italy, which has a 3.9-degree tilt, according to The Guardian. The reason for the slope of the tower is thought to be the result of ground subsidence that happened in the fourteenth century.

The tower is being monitored for any indications of fractures, and sensors have been installed to detect any possible movement. The tower's foundations will be strengthened with modern materials to increase stability. The Asinelli Tower, a well-liked tourist destination, has been temporarily closed for safety as a precaution.

Everyone believes that the base needs to be strengthened due to its historical fragility and the recent issues brought up by the data gathered, according to Cleto Carlini, Bologna's City Hall's coordinator of public works, green spaces, and mobility. "Before we plan the restoration, we need to thoroughly study the question of how," he clarified.

A committed group of national specialists, including geologists, engineers, architects, and chemists, has been studying data from the Garisenda Tower for many years. The data was obtained via optical fibers, a GPS unit on top of the tower, a pendulum, acoustic sensors, and groundwater monitoring systems close to the tower's underground aquifer.

Structuring the Garisenda Tower: A Record of Swaying Repair Designs

In 2021, the base of the tower had heavy iron rings installed around it to protect the fragile selenite stone against future cracking. The higher part of the tower, which was built in the late 1990s using the characteristic red bricks of Bologna, already had iron rings added as a protective precaution, according to The New York Times.

The foundations of the tower and the land below it began to sink in the early 1100s, most likely as a result of a building mistake. The tower was partially shortened by the mid-1300s due to stability issues. The renowned poet Dante Alighieri was so terrified by the tower's conspicuous forward tilting that he compared it to the appearance of the monstrous figure Antaeus in his "Inferno," the first book of his "Divine Comedy"

In the past, specialists had suggested a way to maintain the Garisenda Tower and stop future degradation of its leaning angle: building a number of tall piers with strong steel cables attached. But in the end, this proposal was shelved because of worries that the massive excavation needed for these piers' deep foundations might compromise the stability of the Asinelli Tower, which is located nearby.

Later, a restoration plan was developed that included injecting a particular kind of cement into the tower's base to close the gaps in the selenite stone that had accumulated over time. This proposal, however, never got off the ground because specialists said more testing was required before the project could be carried out.

The present proposal calls for building bulkheads around the base of the tower to stabilize it because the land around it is now restricted. The 157-foot (48-meter) tower will eventually be covered by a secure enclosure while a meticulous restoration plan is chosen.

Mr. Lepore stated that it is yet unclear if the specialists will try to straighten the tower, reinforce the base, or even think about disassembling and rebuilding parts of it to make it stronger. Within six months, he promised, a safety net for the skyscraper would be built.

Bologna celebrated a major accomplishment in 2021 when its vast system of porticoes, or extended colonnades, which spanned the entire city and covered over 39 miles (62 km), was inducted as a UNESCO World Heritage site. The current goal of the city is to enlarge this protected area to include the Asinelli Tower as well as the Garisenda Tower.

Mr. Lepore stated, "Having the two towers on the UNESCO list would help us in terms of maintenance and preservation for the future, as well as in terms of promotion and visibility."