Owner: City of Chicago
In support of the Illinois Department of Transportation’s goal to strengthen the underground foundation for the cities Circle Interchange project, Ballard Marine Construction was on site in support of the prime contractor to assist in the installation of two double section stainless steel bulkheads that were pumped full of grout as part of a process to decommission a section of tunnel. The stainless steel bulkheads were installed in two locations near active pumping stations. Once the bulkheads were installed Ballard commercial divers then tremie poured concrete to fill the last access shaft. Divers worked in cold water temperatures at a depth of 60ft (18m) inside of a 10ft (3m) diameter tunnel and an 8ft (2.5m) diameter tunnel via a narrow access hatch point.
The bulkhead materials and hardware had to be transported on water through the tunnels to the work locations by diver assisted lift bags. During the course of the project divers performed many different types of tasks ranging from concrete drilling for anchor placement to sectional bulkhead assembly with in field changes and modifications performed to ensure proper fit.