Chamber Floor and Wall Repairs at the Chicago Harbor Lock

The United States Army Corp of Engineers, Chicago District is preparing to conduct maintenance work on the floor and walls of the Chicago Lock Harbor to prevent further deterioration and ultimately unsafe conditions. The purpose of the required maintenance work is to create a secure and durable floor to prevent scour and ensure the north and south walls of the lock chamber will withstand forces from extreme weather and impacts from vessels passing the lock chamber. The concrete floor was constructed in 1938 and consists of approximately 250 precast concrete panels, 6x27 ft in size and 8 inches thickness. These panels have been displaced over the years and there are scour holes developed at various locations. The proposed repair work for the floor will consist of the removal of the existing broken and dislodged precast concrete floor panels and ballast blocks. The existing floor base will be dredged to allow for placement of new concrete floor. Reinforced cast-in-Place (CIP) concrete, 22” depth, will be placed over a 6” bedding layer using tremie methods. The contractor will be required to design the appropriate concrete mix for construction in accordance to the performance requirements outlined in the specifications. Rock anchors will be used to secure the concrete floor to bedrock. This repair work will be done under wet conditions. All scour holes will be filled prior to placement of concrete. The Chicago Lock concrete walls were built in the late 1930s with a sheet pile system and 16’ CIP walls cantilevered to the sheet pile system. The proposed work for the walls is to remove an approximately 8-inch thick layer of the existing concrete wall and resurface the them with new CIP concrete. Wall repair work will be done behind a cofferdam to create a dry working area approximately 10x24x14 feet in size. Additionally, 1200 feet of replacement railing, new bollards, cleat replacement, and installation of chains for railing gaps are included in the scope of work.

Division 09 -

Finishes, Flooring, Wall Finishes.