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Corresponding Author

Dina H. Al Sirtasy

Subject Area

Civil and Environmental Engineering

Article Type

Original Study

Abstract

One of the main reasons for bridge failure is local scour at the bridge abutments. Laboratory experiments, under clear water scour condition, were carried out to investigate scour reduction around the vertical bridge abutment by adding one upstream spur dike. Sand with a median and standard deviation of diameter equal to 0.80 mm and 2.173 mm respectively, formed the bed material. Three different stages of spur dikes with varying sets as: 1) distances from the abutment (6 sets), 2) orientation angles (4 sets), and 3) lengths (3 sets), were considered. Effects of all spur dikes are studied with respect to two parameters, i.e., flow discharge and water depth, considering 9 runs for every set with total number of runs equals 99. Empirical dimensionless equation is developed for each set, between the relative scour depth at the abutment corner and the Froude number. Four general dimensionless equations, for the whole sets within every stage, are developed for estimating the relative scour depth in addition to three horizontal dimensions of the scour hole (i.e., relative upstream and downstream scour lengths besides the relative scour width). It is concluded that using spur dikes led to significant reduction on scour depth at the abutment, for the whole stages.Maximum reduction in the scour depth, with percentage 81.56%, is observed for spur dike set with touched distance of the flume wall, between abutment and spur dike, of three times the abutment length, orientation angle of 90°, and vertical spur dike length equals to the abutment length.

Keywords

Scour depth, Vertical wall bridge abutment, Clear-water scour, Flow depth, Froude Number, Open Channel

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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