The Gilmour Street Trunk Sewer project posed unique construction challenges with a particular focus on health & safety. The City of Ottawa selected Greenbelt Construction and Tomlinson to install new underground sewers along Gilmour Street, from Elgin Street all the way to the Rideau Canal.

A key feature of the project was a deep shaft located on the edge of the Queen Elizabeth driveway just a few meters away from the Rideau Canal. Completing the shaft required temporary shoring of the shaft to protect the workers inside. Once the shaft was excavated, Greenbelt then had to excavate a deep, horizontal tunnel which connected the shaft to the existing trunk sewer. “The shaft was narrow as well as deep – only 7 meters in diameter and 15 meters deep,” explains Lyall Steele, Dispatcher and Health and Safety Coordinator, Greenbelt Construction. “Normally we would have more width to excavate to such a depth, but we didn’t have that option. This is the deepest excavation we had performed to date and it presented several potential dangers. Furthermore, the sewers along Gilmour are almost twice as deep as typical sewers, and are close to housing and buildings.” Access, egress, and air quality are some of the potential risks to the health and safety of those working on the project. “Needless to say safety was a paramount concern for Greenbelt for our own employees as well as our subcontractors,” says Lyall.

In order to meet the OHSA requirements for safe access to the site, Greenbelt designed and built a ladder specifically for the project and used cranes to lift employees in and out of the shaft. Since this was a long term work environment at a depth of 15 meters, Greenbelt also monitored air quality constantly. Fresh air was pumped in and circulated properly at all times. As if the health and safety concerns weren’t enough, the City of Ottawa also requested a completion date of June for the shaft. Despite the aggressive schedule, Greenbelt and Tomlinson remained on schedule while addressing the health and safety concerns.