December 11, 1998. Copyright, 1998, Graphic News. All rights 
reserved

WORK TO STOP TOWER TOPPLING BEGINS
By Oliver Burkeman

LONDON, December 11, Graphic News: THE LEANING TOWER of Pisa 
stands in an earthquake zone. One big quake, says historian Piero 
Pierotti, and the marble masterpiece that has wowed the world for 
eight centuries could be reduced to rubble.
	Experts meeting in Pisa this week are expected to decide whether 
to give the green light to the latest scheme to save the cityÕs 
Leaning Tower from the imminent threat of collapse.
The commission of 14 academics should give final approval to a 
proposal by John Burland, Professor of Soil Mechanics at Imperial 
College, London, to reduce the southwards lean of the 
14,000-tonne white marble bell-tower by extracting 1.1 cubic 
metres (40 cubic feet) of earth from underneath the north side, 
provoking controlled subsidence.
If the commission agrees, engineers will immediately begin 
bracing the ÔTorre PendenteÕ with two plastic-coasted steel 
cables, tethering the second storey to counterweights 90 metres 
(98yds) away. That will ready the Tower for the two-year soil 
extraction stage.
But there are no plans to bring the almost 60-metre (200ft) 
landmark, built between 1174 and 1372, back to the vertical Ð 
which, Professor Burland believes, would be Ôa disaster for 
tourismÕ. The tilt will be reduced by just half a degree to about 
five degrees. ÔThat will be enough to guarantee us peace of mind 
for hundreds of years,Õ said commission chair Michele 
Jamiolkowski.
Efforts to correct the tilt Ð caused by the soft silty earth of 
Western Tuscany Ð are as old as the Tower itself, which began to 
lean when the third storey was added in 1274. Architects sought 
to remedy the situation by making the higher levels wedge-shaped.
Since then, 17 commissions have grappled with the problem. 
Proposed solutions have included removing the uppermost storey, 
flying a helium balloon from the top, and forcing a change in the 
direction of the water table Ð because the TowerÕs shallow seat 
of movement leaves it dangerously susceptible to daily changes in 
underground water levels.
The dilemma gained new urgency in 1990, when it was discovered 
that the Tower is rolling to the south, rather than sinking 
faster on one side than the other. That enabled scientists to 
calculate a maximum safe tilt of 5.4 degrees. The current tilt is 
5.5 degrees.
Professor BurlandÕs approach has been widely criticised in Italy 
since September 1995, when his plan to anchor the base of the 
Tower to firm earth 50 metres (167ft) below ground caused it to 
lurch 2.5mm (0.1 inches) in one night, after workers encountered 
an undocumented concrete ring attached to the buildingÕs base. 
Piero Pierotti, an architectural historian at Pisa University, 
says the Tower should be left alone, and claims that Professor 
Burland has done Ôincalculable damageÕ.
ÔPierotti is well known for being completely opposed to the 
project, and he has no technical expertise,Õ responds Burland, 
who says the anchoring system may still be implemented once the 
present plan is completed.
ÔThe one thing you can be absolutely certain about is that if you 
do nothing, the Tower will fall over.Õ
ENDS

Sources: Reuters,
Royal Academy of Engineering, Dept of Soil Mechanics, Imperial 
College, London, Tel: +44 (0)171 594 6079
Associazione Culturale Torre Domani, Tel: +39 547 380455