The U.S. Army Corps of Engineers (USACE) Chicago District and Brennan Construction are operating 24/7 during the off-season to ensure completion of construction on the Chicago Harbor Lock before reopening on April 15, 2024.
Divers are currently replacing tile from the lock floor, which was first constructed in 1938 by the Sanitary District of Chicago, and dredging is being conducted to clear the excess debris. The floor will be fixed with a filter layer, rebar, and concrete.
“Rebar cages are being prefabricated in our parking lot and will be dropped in sections as they go. Once they are in place and tied by the divers, they’ll put top forms on the new form work so it contains all the concrete”, says Michael Shaughnessy, Lead Construction Control Representative with the USACE Chicago Harbor Lock.
“Once the floor is finished then they will start the next phase which will be using drilling rigs to drill micro piles in about 18-20 feet increments down to the bedrock. They’ll grout the new pile and then a bearing plate is added for stability to eliminate uplift”, Shaughnessy says.
Surveys are done by the contractors at every milestone to ensure the right elevation is achieved and is approved by USACE.
The eastern part of the lock walls were repaired last season while the western repairs will be completed during next year’s off-season. This includes using high pressure hydro-demolition equipment to remove concrete, replacing rebar, repainting armor and hooks, adding new handrails and replacing the concrete.
The Chicago Harbor Lock had over 75,000 vessels go through last season (April-Oct.) moving each from river elevation to lake elevation and vice versa. It is one of the busiest in the country for both commercial and recreational vessels.
The required maintenance is needed to create a secure and durable floor and ensure north and south walls will withstand forces from extreme weather and vessels for another 85 years. This helps prevent further deterioration.
Shaughnessy says, “Providing this vital work ensures safe lockage of emergency response, commercial industry, and recreational vessels for years to come.”