Theses defended

Critical infrastructure vulnerabilities. Road network connecting the territory

Susana Freiria

Public Defence date
May 4, 2015
Doctoral Programme
Territory, Risk and Public Policies
Alexandre Oliveira Tavares e Rui Pedro Julião
For several decades critical infrastructure management remained within engineering domains. However, a new paradigm has emerged - a socio-technical paradigm where infrastructures are seen as critical because of their value for society and for a culture. Thus, critical infrastructure operate not only according to technical specifications but also according to constraints imposed by the social environment. The problem is how to integrate in the same model the linkages between infrastructure and social systems. The main goal of this thesis is to propose a new model, the Structural Functional Risk Model - SFRM- a model that identifies the roads that are more vulnerable to interruptions, based on an integrated approach of the structural and functional component of the road network- a critical infrastructure responsible for connecting people, assets and services separated in space. The model is applied to a real road network in a multidimensional perspective, the municipal and regional context. The case studies are from the Central Region of Portugal and Coimbra, a city located in this region. The system used as an example focus the road network as element of connection and access between the parishes and the nearest Hospital - a critical infrastructure of the health sector.
The methodological approach is composed of three main phases: firstly, the road network is assessed in a structural perspective based on the application of a new approach of the biclustering technique; the following phase is focused on the evaluation of the road network in a functional perspective based on a modified gravity model; the last phase is focused on the integration of structural and functional perspective, which resulted from the SFRM. Scenario based approaches are also relevant in this work, focusing on questions such as: what can happen? If it does happen, what are the consequences? A scenario-based approach can be a useful support for a more informed, strategic action. Thus, throughout this work road interruption scenarios will be simulated and analyzed.
The results confirmed the importance of an integrated approach to the structural and functional components. In the assessment of the road network structural component the results revealed that the Biclusters with the highest connectivity are mainly located in the most dynamic economically areas, such as the Coastal zone, and the Biclusters with the lowest connectivity are mainly located in less dynamic areas, such Beira and Transmontana. So, even when the analysis is focused on a network transformed into nodes and edges it is possible to identify relations with the territorial dynamics. The results of the road network functional component assessment point to a significant resource concentration in Coimbra municipality; in the regional context significant accessibility gaps across geographical areas and population groups were identified; even in a normal scenario there are significant disparities in terms of accessibility to health care, which can get worse in a road network interruption scenario. From the integration of the structural and functional component of the road network the SFRM was the result and a step forward, quantifying the share of accountability of each of the components in the road level of vulnerability. The results demonstrate that territorial constraints play a fundamental role in critical infrastructure management; the strategies used in this domain should take into account the specificities of each territory and population characteristics.
This thesis can be seen as a step forward in the consolidation of the socio-technical paradigm as well as a tool for the definition of efficient of prevention measures and the definition of strategies aiming for quick recovery of the system in case of a disruptive event.