BOSTON — ALTHOUGH his plan was conceived 18 years ago, Yao Tzu Li says it could save Pisa's leaning tower. ``It is a well-thought-out proposal, and I still believe it is applicable,'' says Mr. Li.
Then a professor of aeronautics and astronautics at the Massachusetts Institute of Technology in Cambridge, Mass., in 1972 Li submitted his design to an international competition sponsored by the Commission for the Restoration of the Tower of Pisa.
The contest prompted entries from three continents, most of which were deemed amateurish and eccentric. Only 14 were judged by a special panel. Five were ``worth particular consideration,'' according to an official statement. Li's entry was one of them. But all proposals were rejected.
Asked why the contest produced no winner, Li says, ``It was a totally political issue.'' He made a trip to Italy after the contest to question the outcome. ``The government didn't have the solid means'' to implement any plan, he says.
Although uncertain what pushed authorities to close the tower now, Li says, ``Sooner or later there is a point of no return,'' and adds,``it gets harder and harder the longer you don't do anything.''
The basic assumption behind Li's proposal was that the tower is veering from its center of gravity because the ground is unstable. He likened the problem to that of stabilizing an aircraft. The wings support the weight, and the elevator and stabilizer in the tail continually balance the plane. His team proposed adding a set of relatively small pads extending from the main tower base to provide ``dynamic stabilization.''
Told that controlling the water pressure below the tower had slowed its leaning, Li comments: ``Slowing only prolongs the problem. It doesn't solve anything.''