Leaning Tower of Pisa: Behaviour after Stabilization Operations
File(s)
Author(s)
Burland, JB
Jamiolkowski, MB
Viggiani, C
Type
Journal Article
Abstract
It is well known that the foundations of the Leaning Tower of Pisa were stabilised using the method of
underexcavation to reduce the southward inclination of the Tower by about 10 percent in combination with controlling the
seasonally fluctuating water table beneath the north side. Having been closed to the public since early in 1990, the Tower
was re-opened in December 2001. The paper summarises the response of the Tower during the period of implementation of
the stabilisation works. Monitoring of the movements of the Tower has been continuing and the observations obtained since
2001 are presented. It is shown that over the six years between 2003 and 2008 the induced rate of northward rotation of the
Tower has been steadily reducing to less than 0.2 arc seconds per year. Similarly the rate of induced settlement of the
centre of the foundation has been steadily reducing and is approaching the background rate of settlement of the Piazza.
Piezometer measurements close to the north side of the foundation shows that the drainage system has been successful in
stabilising the groundwater levels beneath the north side of the Tower’s foundation. The paper concludes with a brief
discussion on the possible future behaviour of the Tower.
underexcavation to reduce the southward inclination of the Tower by about 10 percent in combination with controlling the
seasonally fluctuating water table beneath the north side. Having been closed to the public since early in 1990, the Tower
was re-opened in December 2001. The paper summarises the response of the Tower during the period of implementation of
the stabilisation works. Monitoring of the movements of the Tower has been continuing and the observations obtained since
2001 are presented. It is shown that over the six years between 2003 and 2008 the induced rate of northward rotation of the
Tower has been steadily reducing to less than 0.2 arc seconds per year. Similarly the rate of induced settlement of the
centre of the foundation has been steadily reducing and is approaching the background rate of settlement of the Piazza.
Piezometer measurements close to the north side of the foundation shows that the drainage system has been successful in
stabilising the groundwater levels beneath the north side of the Tower’s foundation. The paper concludes with a brief
discussion on the possible future behaviour of the Tower.
Date Issued
2009-07-01
Citation
International Journal of Geoengineering Case Histories, 2009, 1 (3), pp.156-169
ISSN
1790-2045
Start Page
156
End Page
169
Journal / Book Title
International Journal of Geoengineering Case Histories
Volume
1
Issue
3
Copyright Statement
(c) ISSMGE 2009. Additional electronic data available from: http://casehistories.geoengineer.org/volume/volume1/issue3/IJGCH_1_3_2.html
Subjects
Leaning Tower of Pisa
leaning instability
stabilization works
Notes
No DOI exists for this.
Publication Status
Published