71
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
1
Kerisel lecture
The role of Geotechnical Engineers in saving monuments and historic sites.
Conférence Kerisel
Le rôle des ingénieurs géotechniciens dans la sauvegarde des monuments et des sites historiques.
Calabresi G.
ISSMGE Technical Committee 301 core member
ABSTRACT: There are many interesting ways for geotechnical engineers to contribute to conservation issues. Firstly they can give a
substantial contribution to the knowledge of the monuments and of their history. Then by assuming a broader, more comprehensive
approach to the conservation issues, based on historical studies, possibly with the cooperation of scholars of different disciplines, they
are often able to identify the nature, characteristics and evolution of the deterioration phenomena and to ascertain the necessity or
opportunity of removing them. Eventually they can propose the less invasive solutions to save the monument and its material
components that bear witness of its origin and history. The paper shows that in some cases this approach can be successfully applied
to save historic buildings, while in others the origin of very slow soil movements, which increase the damage, can be very difficult to
identify and furthermore costly investigations are required. However it is worthwhile to do any effort to achieve a convincing
explanation of the distress causes and to propose interventions that are safe and respectful of the history of the monument.
RÉSUMÉ : Les ingénieurs géotechniciens peuvent contribuer à la sauvegarde des anciens bâtiments et sites historiques de plusieurs
façons. Premièrement, ils peuvent apporter une contribution importante à la connaissance des monuments et de leur histoire. Ensuite,
avec une approche globale des questions de conservation, basée sur des études historiques, et éventuellement en coopération avec des
chercheurs de différentes disciplines, ils peuvent souvent identifier la nature, les caractéristiques et l’évolution des phénomènes de
dégradation et déterminer la nécessité ou la possibilité de les éliminer. Finalement, ils peuvent proposer les solutions les moins
invasives pour sauver le monument et les matériaux qui le composent, témoins de son origine et de son histoire. Dans certains cas,
cette approche peut être appliquée avec succès pour sauver les bâtiments historiques, tandis que dans d’autres, l'origine des
mouvements du sol très lents peut être très difficile à identifier et les études nécessaires pour poursuivre les recherches deviennent très
coûteuses. Néanmoins, il est justifié de faire tous les efforts possibles visant à parvenir à une explication convaincante des causes des
désordres et de proposer des interventions qui soient sûres et respectueuses de l'histoire du monument.
KEYWORDS: Geotechnical engineering, monuments, historic sites, conservation criteria, saving approach, underpinning, micropiles.
1 INTRODUCTION
Since the time when J. Kerisel (Kerisel 1975, 1987, 1997, 2004.
Viggiani 1997, Isnard 1980) and Arrigo Croce (Croce 1980,
1985, Jappelli 1997) raised this issue, the theme of saving
monuments and Historic Sites has gained interest and has seen
an increasing involvement by geotechnical engineers. A
contribution to this heightened interest has also come from the
establishment and the activity of the ISSMGE Technical
Committee (Tsatsanifos and Psarropoulos 2009) and from the
impact of the debate that accompanied the search for solutions
and the implementation of difficult interventions in the case of
very famous monuments like the Tower of Pisa and the
Cathedral of Mexico City. The theme is now a topical one in all
Countries and often involves Geotechnical Engineers, but the
close relationship between Geotechnics, history and evolution
of engineering and architecture is particularly evident in Italy
where towns, buildings and monuments built over a time period
spanning thirty centuries, that are concrete evidence of how
civilization has evolved in the Mediterranean, pose daily
problems to restorers and conservation experts.
In Italy, almost all buildings, monuments and historic sites
have undergone successive changes throughout the centuries.
Their history bears witness to the succession of events, interests,
artistic trends, visions and to the evolution of construction
techniques that have occurred over time. Their conservation
demands contributions not only by the scholars of the Arts and
Humanities, but also by technical experts who are capable of
ensuring such conservation. The complexity of the history and
of the static and conservation conditions of historic buildings
often generates problems in choosing the right intervention
because of the presence of technical difficulties or because of
differences in conservation criteria.
All of this experience deserves being highlighted by
promoting a critical discussion on the role of Geotechnical
Engineers in saving monuments and historic buildings.
2 THE TECHNOLOGICAL PROGRESS OF
GEOTECHNICAL ENGINEERING
It is self-evident that since all buildings interact with the ground
on which they rise and are conditioned by its behaviour, their
state of conservation is affected by any deformation of the soil
and by any changes in its properties occurring naturally over
time or caused by variations in environmental conditions. A
monument, its foundation and the supporting ground should be
considered as parts of a comprehensive complex system, that
any saving proposal should take into account, but the soil is
generally more sensitive than construction materials to stress
variations and weathering; hence it is only natural that
Geotechnics should be involved in discussions on saving and
restoration problems since it is the discipline that more than any
other investigates the nature and causes of soil displacements,
and is therefore the best suited to finding ways of preserving
ancient buildings and monuments.
ris l Lecture
