LRT tunnelling to resume under Rideau Street next week

_ (memo) _ Mayor and Members of Council,

This memo is to provide an update on Confederation Line light rail transit (LRT) construction activities in the Rideau Street area.

Construction underway

As you are already aware, a majority of construction activities have resumed around Rideau Street, following the June 8, 2016 infrastructure failure. Watermain and utility repairs are completed in the Rideau and Sussex streets area. The Rideau Station west entrance has been repaired, sidewalks are open to pedestrians and the roadway has re-opened to transit services and taxis. Work at the Rideau Station cavern, west entrance and east entrance is also underway.

Resumption of tunneling

As with all construction activity undertaken by the City, safety is paramount for both the public and staff working on this project. For the past month, a review of all existing infrastructure and safety measures has been undertaken.

This weekend RTG will resume work beneath Rideau Street between the Rideau Station cavern and east of Sussex Drive. This work is in preparation for the resumption of tunneling which will begin early next week. Approximately 50 metres of excavation remains to complete the 2.5 kilometre tunnel. (Refer to the attached diagram.) Tunnel Excavation

A number of measures are in place to monitor progress and mitigate potential risk:

 The City of Ottawa, RTG and their tunneling experts will be on-site, both above ground and within the tunnel, monitoring activities.

 In accordance with the sequential excavation method (SEM), the tunnel will be mined in small pockets.


 Additional supports including pipe roofing, lattice girders and face bolts will be installed to reinforce the tunnel. Systematic drainage and grouting (injection of concrete to reinforce the area) will occur to mitigate any loose or potentially unstable ground.

 Monitoring of the ground and adjacent buildings will remain ongoing with increased monitoring of the newly installed watermains to detect any settlement or leaks.

Overall, the construction of the Confederation Line LRT project remains on schedule.

I will continue to update you on the progress of the Confederation Line construction. In addition, key stakeholders will be informed of the resumption of tunneling. Should you have any questions, please do not hesitate to contact me at

Thank you,

Steve Cripps

Director, Rail Implementation Office Transportation Services Department