Contribution of relative sea-level rise to bridge failure in the USA during Hurricane Ivan

Abstract

Highways in the coastal environment are subject to storm surge and wave hazards during extreme events. The magnitude of these hazards, and the subsequent vulnerability of transportation infrastructure, will change over time with relative sea-level rise. These changes, which are often non-linear, lead to an amplification of storm-water levels and wave characteristics. These non-linear changes in storm surge and wave hazards, resulting from over three decades of relative sea-level rise between the time of bridge construction (1968) and the landfall of Hurricane Ivan (2004), contributed to span unseating and displacement along the Interstate 10 twin-span bridges over Escambia Bay, Florida, USA. A direct comparison of simulated hydrodynamics at failed bridge spans shows that 36 years of relative sea-level rise resulted in higher storm surge and larger wave heights and greater wave-induced loads. The increase (∼300 kN) in structural demand due to relative sea-level rise is nearly equal to the structural capacity provided by the minimal connections between the deck girders and bent beams. This finding underscores the importance of incorporating appropriate projections of relative sea-level rise into the design of major infrastructure, along with assessments of hazard risk over the expected service life of an asset.

Editorial

“…The second paper (Webb et al, 2020) again covers waves, showing that relative sea level rise as a result of climate change can amplify the impact of waves and storm surge over time. It investigates the contribution of this to infrastructure vulnerability, in particular the failure of the Escambia Bay bridge in the USA (Figure 1).…”

Highways in the Coastal Environment: New Usa Guidance

“…The first, increased flooding, is both increasing frequency and magnitude. The second, more vulnerability, has already been felt as one major US bridge has already been destroyed by the increase in wave-induced loads due to the RSLR rise which occurred during the life of the structure.Recent forensic modeling of the storm surge and waves in Escambia Bay during Hurricane Katrina shows that longterm relative sea level rise (RSLR) likely contributed to the damage which occurred in Hurricane Ivan(Kilgore et al 2019;Webb et al 2020). The magnitude of wave loads in 2004 when the bridge was actually damaged and those which would have occurred if a storm with the exact same characteristics had occurred with sea levels reflective of those 30 to 40 years prior, when the bridge was designed, are compared.…”