Field and Laboratory Investigation of Bridge Abutment: Fid-Bau Portal

Field and Laboratory Investigation of Bridge Abutment

R. F. Carlson / G. Scarbrough / J. Harping

Efficient highway bridge design requires a good understanding of channel bottom scour around the pier and the abutment scour depth equations have so far proved to be not completely reliable when applied to field problems. The authors were able to develop a method depending on simple principles of uniform horizontal that shear distribution, numerical solution of Laplace equation for 2-dimensional flow around the bridge abutments, adjustment of empirial parameters by comparison to laboratory measurements, and the assumption a fully mobile bed sediment movement. The theoretical development results in a prediction of dimensionless scour depth as a simple function of the stream tube contraction at the upstream corner of the abutment. The prediction equation, when compared to laboratory experimental results and a standard regression equation, showed consistent results. When a direct comparison can be made, the prediction equation seemed to give more reasonable results and predicted less scour than that of the standard regression equation. Case studies of two highway bridge crossings near Fairbanks. Alaska showed that the prediction technique has promise as a practical method for evaluating channel scour at bridge abutments.