Restoration works in the city of Venice. Geotechnical aspects.

In restoration and consolidation design the knowledge of the interaction between soil and structure plays a major role in structural behaviour over time. This aspect is particularly important when dealing with the city of Venice, where the buildings are generally characterized by important total and differential settlements as a result of stratigraphic variability and the pressure induced by different types of foundation. The interaction between the construction and foundation as they develop over time must take the building’s history into consideration making full use of archive sources and on-site inspections. In this paper a general outline of the subsoil is presented, based on results from geotechnical investigations carried out in different areas of the city (sestrieri), where the shallow layers consisting of soft medium silty clays and peaty soil alternate between deeper layers of compact medium clay and fine sand. An attempted historical reconstruction of consolidation settlements relating to St. Mark’s bell tower will be presented, as an example of soil structure interaction within the framework of critical state soil mechanics.