Originally protected by riprap, the Spring Creek Bridge abutment was unable to withstand the continual flows of the stream which caused erosion to the toe of the abutment. MODOT District 8 explored several different options to reclaim the abutment and protect it for the design life of the bridge.
In addition to erosion protection on the abutment, a bendway weir (jetty) was constructed upstream to help divert the water away from the east abutment. A-Jacks hard armor units were chosen to reclaim and stabilize the toe of the abutment. Riprap was then placed above the A-Jacks to stabilize the top portion of the slope. The area of protection was expanded, and the A-Jacks were tapered off into the upstream slope to prevent water from getting behind the system.
MODOT employed laborers from the Department of Corrections to install the hard armor. The 24-in. A-Jacks were placed by hand at the base of the abutment in pyramid fashion. Approximately 900 units were utilized to protect 150 LF of streambank. Six laborers were able to install all of the A-Jacks in less than two days.
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