Data-Driven Prioritization and Empirical Predictions for Bridge Scour in Nebraska

The effect of scour at the bridge substructure results in an increase in the vulnerability of the overall bridge stability. Previous studies have found that current guidelines are often overly-conservative with respect to scour. This project aims to provide guidance on hydraulic modeling parameters and reasonable scour estimates specific to Nebraska conditions. This will enable engineers to assess bridge sites for scour more precisely for efficient and effective design and countermeasures. Four sites were surveyed for scour changes between the period of December 9, 2020, to April 20, 2021. At these four sites, overland and bathymetry survey data were collected. The data collected were fused to create a high spatial resolution point cloud data of each bridge site. The point cloud datasets were used to analyze and quantify scour changes in the field using a change detection method. Erosion tests were also conducted at each site to classify the soil properties and determine the equivalent grain size parameters. The fused point cloud data and soil parameters were subsequently inputted in hydraulic modeling software, HEC-RAS, to predict bridge scour and to compare changes over time at each of the field sites. The scour analysis data was directly compared with the quantified changes from the point cloud analysis. The project shows that high-resolution geometry and equivalent grain size parameters yield more reasonable scour estimates compared to current guidelines. Advisor: Richard L. Woo