Impact of Climate Change on Multihazard Performance of River-Crossing Bridges: Risk, Resilience, and Adaptation

Abstract

Enhanced flood hazard due to global warming and climate change imposes an additional threat to safety and serviceability of river crossing bridges. This study proposes an integrated approach to assess how climate change might affect bridge performance under multihazard conditions involving floods and earthquakes. The approach is used for an existing bridge spanning over the San Joaquin River, California. The multihazard impact considering climate change is evaluated in terms of risk and resilience of the bridge. Future flood projections under climate change are obtained from general circulation model simulations in conjunction with a macroscale hydrological model. Enhanced intensities of future design floods are observed to cause higher expected scour at around bridge piers. This resulted in significant rise in risk (−21%) and drop in resilience (−14%) of the bridge, when compared to no climate change scenario, at a specific seismic hazard level. To reduce possible consequences, ripraps are applied around piers as a climate change adaptation measure. Size of the riprap is determined based on the maximum expected design flood flow at the bridge site over the projection period. The applied adaptive measure is observed to be cost-effective through a cost-benefit analysis performed over the remaining bridge service life.