Development of a Decision-Support Tool for Bridge Infrastructure Adaptation in Response to Climate-Induced Flood Risk

Abstract

The 2013 Report Card for the Nation’s Infrastructure, published by the American Society of Civil Engineers, estimates that more than 10% of the over 607,000 bridges in the United States are structurally deficient. Engendering a further sense of urgency for addressing bridge integrity is the impact of projected climate change and associated weather events. The most recent assessment report published by the IPCC concludes that the frequency of heavy precipitation events is increasing along with a concomitant increase in severe flooding. Several software applications are available that perform flood modeling and, in some instances, damage analysis resulting from the flood. Of the software identified, FEMA’s HAZUS-MH, or Hazus, offers a balance between affordability, simplicity and accuracy. Hazus does demonstrate limitations when modeling floods in sub-county areas but at the county-level scale, predicted floods approximate observed floods. Using the US DOT’s HEC-18 guide for bridge scour, a methodology was developed for estimating the monetary damage of bridge scour from a future flood event using flood parameters supplied by Hazus and other readily available resources. Results of the methodology indicated predicted and observed damage values did not exhibit a statistically significant difference (p=0.22, tá=0.05). Additionally, a Pearson’s correlation coefficient of approximately 0.94 was observed. A demonstration of the methodology application was performed in which several bridges in Little Rock, Arkansas were assessed for adaptation planning prioritization.