| The different topological characteristics of a transportation infrastructure system are investigated by developing a procedure that simulates the interactions between two infrastructure components when they undergo disruption. The components are assumed to be uncongested so that evacuation as a means of disaster response can be easily implemented. The characteristics considered for the static analysis include the characteristic path length, vertex degree distribution, network density, clustering coefficient, betweenness centralities, connectivity loss and efficiency. Through scaling and statistical analysis, these characteristics are used to assess the nature and performance of a system of two infrastructures, namely the New Castle County, Delaware highway network and bridges, after a perturbation. The infrastructure system formed is analyzed so as to obtain its initial characteristic properties where the disruptions in the system are implemented using two main node removal strategies namely random and targeted node removal strategies while the interaction between the two infrastructures are quantified using the interaction response. The initial equilibrium points for each property resulting from applying the disruption strategies are first assessed to ensure that they represent limiting values for introducing resilience in the system. This is achieved by selecting the equilibrium point value of the average shortest path distance property as well as four trial values around it to represent limiting values for refining the analysis so as to obtain a new set of properties which are compared by using their correlation coefficients. The limiting value that yields the most prominent correlation coefficients when the properties resulting from the analysis under the corresponding disruption strategies are compared is identified. Thereafter, the points of convergence under each property are then used as further limiting values for reanalyzing the network. The process is repeated until a final network is obtained in which the properties are consistent and the equilibrium point values remain uniform. Consequently, an assessment of resilience of the final network and its reaction to random and intentional attack is carried out. |
