Use of corridors to select bridges to retrofit in road networks in seismic regions

This study proposes the use of bridge clusters, defined as Corridors, to support optimal bridge retrofitting strategies for seismic risk management of road networks. A Corridor is defined as a set of bridges that works jointly to ensure connectivity and traffic flow between different areas of a region. To detect Corridors, a Markov Clustering Algorithm is proposed. Using the San Francisco Bay Area road network as a testbed, this clustering technique selects sets of bridges that correspond to main traffic arteries such as highways and high-capacity road segments. After Corridors have been detected, a two-stage stochastic optimization is implemented to detect which bridges should be retrofitted to ensure an acceptable network performance. This optimization couples retrofitting actions in a Corridor with the repair actions to damaged bridges after an earthquake. The Corridors-Supported Optimization decreases road network disruption more than other approaches based on ranking bridges according to their traffic capacity or location in the network.