REDUCTION OF LOCAL SCOUR AROUND OBLONG BRIDGE PIERS USING SLOTS

H. Saleh, Hend; Abozeid, Gamal; S. Darweesh, Moustafa

doi:10.21608/jaet.2020.75171

REDUCTION OF LOCAL SCOUR AROUND OBLONG BRIDGE PIERS USING SLOTS

Authors

¹ M. Sc. student, Eng. At Ministry of water resources and public work, Egypt

² Professors of hydraulics & water resources, Civil Eng. Dept., Assiut Univ., 71516

³ Assistant Professor, Civil Engineering Dept., Assiut University, 71516 Assiut.

10.21608/jaet.2020.75171

Abstract

This article presents an intensive experimental work for investigating the effect of rectangular slots and pier groups with various arrangements on the scour around bridge piers. Slots near the bed through an oblong pier with different arrangements and replacing the solid pier by two pier groups were provided to show their influence on the variation of scour dimensions under clear-water conditions. Water flow rate is varied four times (18, 15, 12.5 and 10.5 lit/s), while the water depth covers a range of Froude numberfrom 0.089 to 0.25 which is suitable for Egyptian canals. The scour hole dimensions and water depths are measured using calibrated point gages. The factors impacting the scour problem are normalized with the help of dimensional analysis theory. The experimental results show the efficient method that decreases the scour hole dimensions is the pier groups (pier type 7), where the scour depth, width and length reduced by 93, 73, and 79 % respectively. Slots within the oblong piers decrease the scour dimensions (depth, width and length) by 92, 53, and 69 %, respectively. These findings can easily safeguard the bridge piers and dramatically reduce the maintenance efforts and costs as well as improve the hydraulic performance of the water structures.

Keywords

Main Subjects

Civil Engineering.

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