The present research project is aimed at developing a novel approach to the assessment of the damage produced by major earthquakes to strategic infrastructural systems. In this approach, a limited number of specific instruments are installed at carefully selected locations. The decision about the type and location of the measuring devices originates directly from the results of non-linear dynamic analysis of numerical models that describe with good accuracy the mechanical response of the system under examination.
The infrastructural elements considered in this project are those that present distinctive interaction with the subsoil, namely, large earth dams, major tunnels, and large bridges, limiting in this last case the study to a damage related to the soil-structure interaction for the foundation and the abutments.
Note that this is different from the common definition of a dynamic structural monitoring, as the scope is not the evaluation of the dynamic behaviour of the system structure under low-intensity motions: the objective is to evaluate directly and rapidly the actual damage produced by a major event, to assist a decision about the integrity and operability of the system. Therefore, it can be anticipated that in the selection of the measuring devices, static measurements will be preferred to dynamic ones, and that the robustness of the instrument will be the preferential selective criterion, in addition to its accuracy, while the potential to generate automatic measurements does not appear particularly advantageous.
The proposed research project aims at developing a more rational methodology for the assessment of the damage produced by strong earthquakes on large infrastructural elements (large earth dams, major tunnels and large bridges). In these cases, the interaction of the structure with soil is a crucial aspect than need to be considered in predict the evaluation of the parts potentially more susceptible to damage and, accordingly, for a robust planning of the monitoring system. A rational monitoring would lead to a much more efficient data acquisition, resulting in a very rapid evaluation of the actual damage occurred to the system after the earthquake.
In order to reach the objectives above, the research group will work to obtain a better understanding on the seismic behaviour of these large systems, with the aid of advanced numerical analyses able to simulate the salient aspects that govern the dynamic response of the structure and of the geotechnical systems. Several soil-structure systems will be analysed as representative of the Italian territory to define a benchmark of general validity for the detection of the parts more susceptible to damage.
Another element of innovation consists in analysing the combined effect of the nonlinear behaviour of soil and structural elements, with the aim to reach a comparable level of accuracy between structural and geotechnical modelling. As a result, it will be possible to have a more accurate description of the overall dynamic response of the system and a much more likely prediction of damage localization and control.
Finally, a new way of understanding monitoring of large infrastructural elements could also lead to reliable design criteria, with a more efficient identification of the dissipative zones activated during strong shaking, both in the superstructure and in the soil. Hence, the proposed research project points to an extended concept of resilience, in which damage of foundations can be regarded as a winning element for an improved seismic performance of the whole system, provided that it is well thought out, controlled and monitored.