- For centuries scholars have worried over
the Leaning Tower of Pisa's increasingly drunken angle. Now, scientists
have pinpointed the exact degree at which the Italian tower will tumble.
-
- The project was carried out recently
by Lillian Schwartz, a consultant in computer graphics-video at Bell Laboratories,
and Madara Ogot of Rutgers University.
-
- "Using drawings supplied by the
Commission for the Preservation of the Tower, we built an accurate three
dimensional computer model," explains Schwartz. "The model allows
us to carry out stress analysis on the structure and can predict at what
lean angle the tower will collapse."
-
- The tower currently leans at 5.6 degrees.
Another 1.4 degrees will be enough to bring 14,000 tons of intricately
carved white marble crashing to the ground, according to Schwartz's tests.
-
- At 7 degrees the model shows that walls
cannot support the structure anymore. High-tension areas on the lower floors
on the northern side caused the bricks to pull apart.
-
- However, Schwartz believes that this
dreadful scenario will not occur in the near future. "The structure
is really good," she says. "It could last another 75 to 100 years,
if the soil holds."
-
- The soft, sandy subsoil is what has given
the tower its lean since Bonanno Pisano began building it in 1173. In 1990,
the tower had to be closed to the public.
-
- Keen to re-open Pisa's landmark in time
for the millennium, the committee has started frantic work to keep the
tower aloft.
-
- By October, the monument will be wearing
a pair of steel "suspenders," which should brace it while a girdle
of steel anchors is built around its foundations. This should pull the
tower two centimeters back from its lean.
-
- "It will be enough to guarantee
our tranquillity for hundreds of years," says Michele Jamiolkowski,
president of the committee.
-
- Yet the computer model shows this could
be an extremely hazardous task.
-
- "We think, but need to do more tests,
that the cables may shear the top off," says Schwartz, who is willing
to collaborate with the committee before any structure is built around
the tower.
-
- So far, any help has been declined.
-
- "There is a total absence of a forum
for discussion," says Prof. James Beck, art history professor at New
York's Columbia University, and director of Artwatch, an organization that
opposes art restorations without an international panel's study. "Really,
the best thing they could do is to leave the tower alone."
|
