Probabilistic Flood Loss Assessment for Bridge Infrastructure Subjected to Scour
Open Access
Author:
Kern, Michael
Area of Honors:
Civil Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Kostas Papakonstantinou, Thesis Supervisor S. Ilgin Guler, Thesis Honors Advisor
Keywords:
Scour HEC-18 HAZUS Flood Loss Bridge Failure Probabilistic
Abstract:
Scour is the erosion of soil surrounding a bridge foundation. It is the leading cause of bridge failure in the United States. Pennsylvania’s poor bridge infrastructure and its susceptibility to flooding compound to form a detrimental relationship that exacerbates the impact of scour. After establishing the importance of scour estimation, a deterministic approach to estimate a bridge’s failure probability due to scour using FEMA’s HAZUS Flood software for hydrologic, hydraulic, and damage estimation is outlined. To incorporate the various factors of uncertainty that are not addressed in the deterministic
approach, a probabilistic methodology using inundation maps for hydrologic analysis, Manning’s equation for hydraulic analysis, and the HEC-18 pier scour equation for damage analysis is presented. A limit state function is established to define failure. The deterministic and probabilistic approaches’ results are compared for a study centered around the PA-39 Swatara Creek bridge in Dauphin County, PA. It is found that the probabilistic estimation generally estimates a larger failure probability, and is effective over a greater range of peak flood flow rate values. Climate change’s increase on future flood peak flow rates and its impact on scour are briefly discussed.
