The monitoring of structures is a specialised technical area which is currently developing rapidly. Well-delineated monitoring plans allow us to draw inferences about the behaviour of structures and their evolution over time, in particular the evolution of damage – and in that last case, may act as an alert system.

Defining the monitoring plan is essential for carrying out any such campaign. It allows an action strategy to be defined that is directed at the anomalies, or at the behaviour of the construction to be observed, as well as enabling the choice of equipment to be tailored to the objectives and conditions existing on-site. Monitoring campaigns may involve measuring absolute or relative displacements, slopes, cracks and joints openings, and may involve the use of more or less complex sensors, whether mechanical, electrical, wired or wireless.

Monitoring campaigns are usually planned for an extended period, generally longer than 12 months, so that it is possible to exclude the influence of seasonal temperature and humidity variations from the measurement results. Sometimes it is only possible to draw conclusions about the stability, or not, of existing damage after such a period.