Technical Description:
• 24-in. A-Jacks
®
• Units: 5,124
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During an inspection of an existing multi-span steel beam bridge over White Oak Creek in Brown County, Ohio, it was noted that the piers and slopes to the abutments were subjected to major scour. Since the bridge itself was in fair condition, Ohio Department of Transportation (ODOT) searched for a mitigation option in the hopes of postponing a full replacement for at least ten more years.
Comprised of fractured rock, the highly volatile stream channel paired with the highly erodible stream bed caused major erosion and scour to occur around the piers. Various solutions were discussed but because of the high stream velocity and the amount of shearing that had already occurred, traditional solutions such as rock channel or dumped rock protection were ruled out.
For these reasons, ODOT hired Coopers Excavating to install 5,124-24" A-Jacks® Hard Armor units as the best, most permanent engineered solution for this project. A-Jacks concrete armor units are designed to interlock into a flexible, highly permeable matrix. The ability of the A-Jacks system to dissipate energy and resist the erosive forces of flowing water allows it to protect against scour and erosion.
In the end, A-Jacks provided a robust solution to mitigate the scour while allowing ODOT to prolong the bridge life for another 11 years until it required full replacement in 2022. The new structure was designed on a new alignment that eliminated the need for piers to be built in the creek. The A-Jacks performed as promised, and ODOT was pleased with the outcome.
“The A-Jacks performed quite well in those specific areas in the stream to mitigate further stream erosion,” concluded W. Max Francis, P.E., District Structures Planning Engineer with ODOT District 9.
Technical Description:
• 24-in. A-Jacks
®
• Units: 5,124
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