On the stability of Santo Stefano bell tower in Venice

In the framework of the stability of leaning towers, the Santo Stefano bell tower, in Venice, is an interesting case study for both its current structural arrangement and the notable rotation it has undergone over the centuries. In addition to describing of the main structural features of the tower and its historical Venetian foundations, the paper presents and discusses the main outcomes of a geotechnical investigation carried out on the foundation and the subsoil beneath it. The case history has provided an opportunity to introduce an analytical tool that can deal with the two major collapse mechanisms of tower foundations: bearing capacity failure, due to lack of soil strength, and instability of equilibrium, due to lack of soil stiffness. Both of these hazards are tackled using a work-hardening plasticity model for surface footings. The paper describes, as its main contribution, the methodology for an integrated approach to these problems specifically in relation to the Santo Stefano bell tower. This approach may be a useful tool for the study of the influence on the stability of the tower of remedial measures carried out at the beginning of last century or for the study of similar historical monuments.