Midwest winters can be harsh and bitterly cold. The northern portion of the Mississippi River freezes over, bringing the boat and barge traffic to a halt. However, the maintenance of these vital waterways continues. These months are utilized to make repairs and refurbishments the river and it’s structures, such as the locks and dams, as to not impede marine traffic.
Many years of wheel wash from tugs damages the wall footings. Winter 2017/2018 brought the undertaking of refurbishing portions of those footing on lock 6 and 8. These locks required stabilization of the approachment walls, located upstream and downstream of the lock chamber. Tugs, with tows attached, use these walls to help guide them into the lock chamber. This was accomplished by installing forms to both the upper and lower portion of the approachment wall measuring 500 linear feet each. Numerous locations required forms on both the river and land side of the wall. Flowable fill was then pumped behind the forms, cured, and forms removed stabilizing the wall’s foundation. Lock and dam 5 and 9 received similar restorations winter 2018/2019.
Winter 2017/2018, crews assisted with the stabilization of the lock chamber floor at lock and dam 18. The divers aided in the drilling rig cutter head positioning. Once the access hole was placed, valving and pressure gauges were installed to monitor the differential pressure under the floor. Flowable fill was then pumped under the lock floor providing stabilization from the differential pressures that are encountered during the continual raising and lowering of water levels within the lock chamber.