Leaning Tower of Pisa Ready to Reopen

ByABC News
May 16, 2001, 12:29 PM

L O N D O N, May 16 -- Engineers who toiled for more than a decade to stabilize the leaning Tower of Pisa are standing tall.

Today they are set to finish peeling away the last of two sets of steel suspenders supporting Italy's famous monument.

The cables were secured in 1998 as part of a bold, apparently successful plan to straighten the tower. Some had feared the icon of Italian culture might begin to slip as workers excavated the soil under its foundation.

'Extraordinarily Close' to Collapse

Although the Tower of Pisa has always leaned since its construction began in 1173, the most severe threat to its stability did not come until the 19th century. By adding a walkway close to the monument, engineers unintentionally shifted the soil underneath the tower.

This seemingly harmless act gradually caused the lean to worsen by several inches. The Italian government formed a commission to find a way to prevent any further slide.

"It's not often widely appreciated that the tower was literally on the point of falling over," says John Burland, a professor of soil mechanics at London's Imperial College who worked on the project. "Anything we did was extremely delicate."

But throughout the repair process, the tower proved strong enough to stand on its own. Or to be more precise, Burland points out, the tower's foundation was solid enough to hold up against the strain of the latest modifications, thanks to some grouting work done in the 1930s.

The steel suspenders were attached to giant winches buried 100 yards into the ground in case the tower slid further. In the end they were never needed.

A Big Sigh of Relief

"It's a little like running a marathon," Burland says of saving the tower. "You're concentrating so hard that before you know it you're crossing the finishing line."

Burland acknowledges the nature of the project put an extraordinary amount of pressure on him and his colleagues.

Tourists are more likely to notice they will be able to climb the monument for the first time in a decade than the 16-inch difference in the tower's lean.