Non-invasive imaging of ancient foundations status in Venice (Italy) using the Electrical Resistivity Tomography technique

Electrical Resistivity Tomography (ERT) has proved to be an outstanding non-invasive technique to evaluate the degradation state of historical buildings, both under normal dry conditions and when materials are saturated with salt water. An ERT test was undertaken along a portion of a canal's wall located in Venice (Italy). The walls of the canal serve to protect the bank from damage, caused mainly by wave action generated by the transport vessels. Preliminary information, a.s.1., collected by visual inspection, reported local absence of cement between the bricks, and the presence of less compacted materials behind the bricks. Based on these evidences, the ERT survey was performed to investigate the walls conditions both above and below m.s.1. The estimated distribution of the electrical resistivity suggested the presence of highly degraded zones within the first 30 cm of the wall's surface. These findings were useful for the restoration project.