Stabilizing the Leaning Tower
by Don Barker
On June 16 2001, the Leaning Tower of Pisa in Italy was officially reopened during a colorful ceremony that coincided with the feast of Saint Renieri, Pisa's patron saint.
After ten years of tower rehabilitation, its ancient key was ceremonially handed back to the church guardians, who climbed the tower's 297 steps. This marked the start of two days of celebrations that included a candle-lit procession along the banks of the River Arno and an open-air concert by tenor Andrea Bocelli.
The tower will not open to tourists until November 2001, and even then the number of visitors will be limited to between 25 and 30 at a time.
The $30 million project to stabilize the 12th-century bell tower is being hailed as one of the great engineering feats of all time, making the 200-foot- (60-meter-) high tower safe for the next 300 years.
Two years ago, specialists came up with the solution to slowly remove soil from the north side of the tower's foundation so that it would right itself.
This procedure reduced the lean by 20 inches (50 centimeters) as measured in a horizontal plane at the seventh cornice. This returns the tower to the lean it had in 1838.
John Burland, professor of soil mechanics at Imperial College in London, devised the soil removal system. Polish-born, Milan-based engineer, Michele Jamiolkowski, headed the rescue team through a number of government changes and constant criticism.