Italy races to stop leaning tower from collapsing

The towers in Bologna date back to the 12th century. (Francesco Riccardo Iacomino/Moment RF/Getty Images via CNN Newsource)

It's become Italy's other "leaning tower." And now, after mounting concern that the Torre Garisenda in Bologna might be on the verge of collapse, a plan has been hatched to save it using the same equipment that shored up the Tower of Pisa.

The 48-metre (158 feet) Garisenda tower was built in the 12th century, during a boom period of the northern city's history, but two centuries later it had already begun to tilt. Today, it leans at an angle of four degrees, just a little more than the Pisa tower's current 3.9-degree slant.

Late last year, the streets around the Garisenda were temporarily sealed off as scientists monitored the structure for evidence of movement and cracking, concluding that it was at "high risk" of collapsing.

Bologna's mayor, Matteo Lepore, announced on Wednesday that pylons and cables previously used to save the tower in Pisa would be deployed along with adapted steel scaffolding to help prevent it from breaking apart.

"This will make it possible to secure the tower," Lepore told a press conference. He said it could allow the Asinelli Tower, a taller structure that stands next to Garisenda, to reopen to the public.

"In 2025 and 2026 there will be further consolidation and restoration work, which still needs to be planned," Lepori added.

Literary fame

The mayor said it should take "about six months" to adapt the equipment used for the Tower of Pisa to Garisenda, with the entire safeguarding operation priced at an estimated 19 million euros (about US$20 million).

Once the two steel pylon structures used in Pisa are erected and adapted to Garisenda, consolidation work will begin on the tower's masonry, including injections of a lime-based mortar mix compatible with the one used in the building's original construction, according to a municipality press release.

Then cables connecting the pylons to scaffolding attached to the tower would be tightened, a procedure that would decrease stress levels at the tower's base.

While less well known than its counterpart at Pisa, the Torre Garisenda has long been a tourist attraction in Bologna. Its unusual angle earned it a mention in Dante Aligher's 14th-century poem "Divine Comedy." Alongside it, the taller Torre degli Asinelli is also a tourist attraction, with a more modest lean of 1.3 degrees.

The Tower of Pisa, the centerpiece of a UNESCO World Heritage site, reached a lean of 4.5 degrees in the early 1990s. Fears for its stability led to an international effort to stop it from toppling over, with work lasting eight years from 1993.

Today the bell tower is a stable monument mainly thanks to those steel pylons which will hopefully give the Garisenda tower a second life.