As part of the 4th Avenue Flyover Bridge Rehabilitation Project EllisDon is currently working on for the City of Calgary, extensive in-stream pier repair work for the center pier was required to move forward. 

Our civil team effectively managed this unique scope, which involved working with a temporary works engineer to design and build a steel “dry box” assembly that could be lifted with a crane from the bridge above and installed around the center pier.

Commercial SCUBA divers (Aquatech Diving & Marine Services Ltd.) were brought in to utilize special tools such as underwater hammer drills and jackhammers to install the dry boxes while working in the river current. SCUBA teams also performed video inspections underwater as part of the Quality Control program requirements. Once a watertight seal was achieved using a specialized gasket system, EllisDon self-performed concrete demolition and restoration while adhering to strict environmental permitting restraints and constant monitoring.

This in-stream scope of work was successfully completed over a three-week period in August, while the EllisDon civil team continued to safely maintain and manage active traffic on the bridge, which allowed for one of the City’s main arteries into the downtown core to remain open.

A massive shout-out to the Calgary team for achieving a successful milestone on this intricate, niche part of the project!