Analysis of the soil-structure interaction due to tunneling under Palazzo Strozzi in Florence (Italy)

In order to contribute to solving traffic and mobility problems in the urban area of Florence, a team of researchers of the University of Florence studied the possibility to adopt an innovative underground rapid transport system, called “Micro-Metro (µM)”, running in a one-way tunnel with a small section. For assessing the risk of damage to buildings due to tunnelling, the classical approach based on the empirical estimate of the settlement trough at the ground surface and of the limiting tensile strains in masonry walls was adopted. For the most important historical and monumental buildings existing along the route of the µM, a more detailed soil-structure interaction analysis was carried out. In this paper the case of Palazzo Strozzi, which is one of the finest expressions of Renaissance architecture, undertaken by Benedetto da Maiano in 1489, is described. The tunnelling excavation effects on the building have been evaluated not in term of visible cracking but in term of reduction of the masonry's capability to resist to cracking, even before this is verified.