Abstract:
Damage from recent earthquakes has shown that substandard bridges are particularly vulnerable to strong ground motions being the weakest components of a road network. Structural and foundation damages in bridges lead to a significant loss related to both repair process and a prolonged traffic disruption, which in turn results in large indirect loss in the affected area. Along these lines, the estimation of the overall loss related to earthquake-induced damage in highway bridges and overpasses must be based on a wider network analysis rather than on a single structural assessment. Key concept in such a comprehensive loss estimation procedure is the network resilience, expressing the extent of both direct and indirect loss, as well as the system's ability to quickly recover its pre-earthquake state. In this paper, a recently developed framework for assessing the loss and resilience associated with seismic impact on the structural and geotechnical components of a road network, as well as the relevant software developed are extended to further consider the implications of post-earthquake traffic demand variation. Moreover, a sensitivity analysis is conducted for a case study network to investigate the impact of traffic demand variation after a major earthquake event and the subsequent trip cancelations on the time-variant, cumulative cost at a network level. The results clearly highlight that not only the seismic resilience of a highway network should be assessed in a holistic manner coupling seismic hazard, structural and traffic analysis, but the latter shall include realistic scenarios with respect to the potential variation of origin-destination demand after the earthquake and during the recovery period.