Review of Bridge Scour Practice in the U.S.

Development of a Risk Assessment Module for Bridge Management Systems in New Jersey

“…An accurate evaluation of the probability of failure of bridges resulting from scour requires several pieces of information from different engineering fields, hydraulic, geotechnical, and structural. Most of the probabilistic work done on the effect of scour on bridges, like the HEC-18 method ( 32 ), focuses on how to estimate the magnitude of the scour depth on pier foundations and abutments. However, once the scour depth is known, a full structural analysis of the bridge should be performed to quantify the probability of failure.…”

“…The average channel height during the discharge Q is estimated to be 3.20 m. The ratio between the discharge upstream and that downstream the bridge is assumed to be equal to 1.10. The height of the soil around the foundation prior scour is assumed to be 1.52 m and the width of the piers perpendicular to the water flow is set equal to 1.0 m. Finally, in New Jersey the average resistance of the soil to erosion is estimated to be hard cohesive granular soil (G1), which is characterized by a median soil diameter d 50 equal to 22 mm and the 84 percentile diameter, d 84 equal to 36 mm, respectively ( 32 ). These values, plus the width of the navigation channel extracted from the NBI database, are the minimum set of parameters needed to apply HEC-18 for determining the scour depth at the abutment, as well as contraction and local scour around the piers.…”