Pisa's Tilted Tower of Controversy

QUESTIONS have often been raised about whether the Leaning Tower of Pisa was born bent. In fact, the legendary list that has made the tower a marvel for medieval scholars and an enigma for engineers the world over first started when the ground beneath it shifted only a few years after construction began in the 12th century.

Now, the campanile is swirling in a controversy over just how much longer it can continue its gravity-defying stand. The debate was touched off by a recent report by the Italian Ministry of Public Works warning that the 14,000-ton marble monument was in imminent danger of toppling and suggesting it should be closed for repairs.

As a result, Pisa's mayor, Giacomo Granchi, decided to make one of Italy's top tourist attractions off-limits for the first time. Bells tolled out a dirge in mourning on Jan. 7 when the tower was closed.

``Closure of the tower is mortifying for us and all Pisans,'' said Antonio Lazzarini of the Monument Preservation Committee, which oversees its maintenance. ``It's definitely a defeat.''

In principle, Mayor Granchi was against closing the tower. He only grudgingly signed a temporary closure order after weeks of wrangling with Public Works Minister Giovanni Prandini failed to give the tower a more permanent reprieve. And to prevent bureaucratic delays from keeping the tower closed indefinitely, Granchi has vowed to reopen it unless restoration work begins in three months.

``We're waiting to see how the government will respond to the mayor's challenge,'' says Mr. Lazzarini.

The mayor, who is backed by a bevy of local experts, argues that the commission sounded a false alarm and contends the tower is not at any greater risk now of collapsing than in the past.

Piero Pierotti, an expert on medieval architecture at the University of Pisa, acknowledges that the ground beneath the tower is unstable because of a fluctuating water table and that the marbles of its graceful loggia are heavily damaged. In a telephone interview he insists, ``I'm convinced the tower is not in any more immediate danger of falling than it was before.''

Indeed, most experts believe the tower - which now leans some 13 feet off-center at its top - could resist gravity at least another century. If anything, they say, the latest measurements are proof that the tower's tilt is not getting worse. In June, the tower had only moved 0.2 millimeters (1/125th of an inch) the previous 12 months, well under the 1.1 millimeter average since monitoring began early this century.

One concern for Mayor Granchi's Pisan constituency is that the tower's closure will dry up tourist revenues. Pisa can count on some 800,000 visitors to the tower each year. This adds up to some $2 million in tickets alone, a respectable contribution to the maintenance of Pisa's monuments.

BUT Giulio Carlo Argan, a noted art historian, complained in a newspaper article, ``It's indecent that monuments have to earn a living to survive.'' Mr. Argan says the weight alone of the throngs is a serious hazard and is relieved the tower will be getting a rest.

Attention was fixed on the precarious state of the Pisa tower after a medieval tower in the northern town of Pavia collapsed last March killing four people.

Pisa's plight is not unusual in a country whose trove of archaeological and artistic treasures is in constant need of repairs. Only this summer in Verona, the balcony that tradition says is the one from which Juliet entreated Romeo started crumbling.

In its checkup report, the 166-member special commission reporting to Mr. Prandini diagnosed the Leaning Tower of Pisa's ailments and came up with the prognosis: Without urgent treatment, the tower could topple ``without warning.''

Prandini's cure - the proposal of a team of five engineers - centers on construction of a giant scaffolding that would shroud half the tower. This metal girdle would provide a platform for workers during restoration of the delicate marble of the loggias.

The most significant aspect of Prandini's plan is that it aims to finally solve the problem of the tower's unstable base. The metal scaffolding would secure the structure while its foundations are anchored by giant spokes to a ring of cement.

Virtually ever since the tower's first stone was laid in 1173, based on designs by Bonnano Pisano, the ground has shifted beneath it. When only three tiers were finished, the tilting began and construction was eventually halted.

The tower's base has always been subject to sinking since it is layered underneath with clay and sand, and waterways cross the spot at a depth of some 30 meters (98 feet), says Mr. Pierotti.

The campanile was only completed in 1303 after Giovanni di Simone devised an ingenious solution based on the complex balancing of weights that enabled him to build a light, graceful structure atop an already faulty foundation.

Should Prandini's plan be executed, Pierotti fears it will destroy di Simone's architectural alchemy. ``The project was drafted by engineers who know nothing about medieval architecture,'' he laments. He is convinced the cure the engineers have proposed - and that was accepted by the ministry last year - is far worse than the problem. He remembers that three years ago the commission was suggesting the belfry be removed to lighten the tower. The weight of the 14th-century belfry, according to Pierotti, acts as a counterbalance to the tower's tilt.

The danger of a botched restoration looms large in Pisa. After one ill-advised attempt to consolidate the ground in 1936, the tower slipped by as much as three inches.

Furthermore, Pierotti attacks the engineers' assumption that the tower's dry stone masonry can be solidified by injecting the interstices with cement. ``These hollow spots serve to both lighten the tower and make it flexible,'' says Pierotti, insisting that the loose filling in the walls was part of di Simone's plan and that a good restoration must respect the use of original materials.

The use of cement is therefore anathema to Pierotti. The University of Pisa art historian is also petrified the tower's marbles would crumble in the metal grip of the girdle and that the planned excavation around the base could actually precipitate rather than prevent the tower's fall.

FOR now, it appears the ministry's master plan for the tower has been put on hold, much to Pierotti's relief. Rather than implement the ministry's blueprint, Pierotti would prefer to dismantle the tower ``scientifically'' stone by stone before putting it back together again. That way, he says, the tower's secrets would finally be revealed.

Meanwhile, he hopes restorers will immediately begin repairing or replacing the marble columns that he says have been neglected for some 30 years.

The Prandini plan capped a long series of attempts to solve the Leaning Tower of Pisa's predicament. An international competition held in 1972 yielded some 22 plans, none of which was ever accepted (see related story).

Through the years the search has yielded some strange solutions for salvaging the tower. The preservation society charged with the tower's upkeep is regularly swamped with mail prescribing remedies from around the world.

A group of American schoolchildren suggested the campanile's rim be hooked to a hovering helicopter. Perhaps the zaniest idea was that of a well-meaning Florentine who proposed to erect a huge statue of Saint Ranieri, Pisa's patron saint, that would hold up the tower with the tip of his sword.