1. Who is involved in the tunnel project?
The tunnel project is being delivered on behalf of Ports Toronto through a public private partnership model. The private sector consortium delivering the project comprises: Forum Equity Partners (Concessionaire and Equity Sponsor), PCL Constructors (Design-Builder), Johnson Controls (Facility Manager), Technicore Underground (Tunnelling Contractor); Arup (Lead Designer), ZAS (Architect), and Exp (Geotechnical Engineer).
2. What is being built?
The project includes an under-lake tunnel that will span the Western Gap in Toronto Harbour and allow pedestrians access between the Billy Bishop Toronto City Airport’s mainland and island terminal buildings. In addition to the pedestrian tunnel, the project involves the construction of a new, one-storey pavilion at the foot of Eireann Quay, an addition to the existing terminal building on the island as well as water and sewage service lines that are being constructed on behalf of the City of Toronto.
3. When will the project be completed?
Construction is scheduled for completion in Late July 2015. The project’s key milestones include:
- Completion of the enabling underground services relocation
- Completion of the drift tunnel excavation
- Completion of the pedestrian tunnel excavation
- Completion of the new Island-side addition
- Completion of new mainland-side pavilion
4. What type of construction activities will be taking place?
Construction activities that will take place over the duration of the tunnel project include:
- Underground utility relocation (hydro, water, sewer, etc.)
- Shaft excavation on mainland and island. The shafts are constructed using the secant wall method, which utilizes a series of interlocking concrete cylinders to provide structural stability during shaft excavation.
- Tunnel boring and excavation.
- Removal of spoil (i.e. excavated earth and rock material) from the construction site
- Construction of a one-storey elevator building on the mainland and an addition to the terminal building on the island side.
- Installation of elevators, at both ends of the tunnel, escalators on the tunnel’s south end (island side) and moving sidewalks within the tunnel.
5. What is a concrete batching assembly and why is it being used?
The concrete batching assembly is electrically powered equipment that is used to measure and mix the ingredients to make concrete. The concrete batching assembly does not produce exhaust emissions (i.e. it is electrically powered).
The batching assembly is being used to minimize the number of trucks that will deliver concrete to the site therefore making the construction efforts more efficient. This equipment is portable and will be on site for a portion of the construction program (i.e. it will be removed from site once the project’s requirement for concrete is complete). The assembly is situated on a newly (i.e. temporarily) paved area within the Canada Malting Site and comes equipped with dust mitigation features (designed to a minimum efficiency of 99.9 per cent). These aspects have been established to help minimize any dust generated on site.
The batching operation allows trucks to deliver gravel and aggregate (i.e. the ingredients for concrete) and leave the site full of excavated material (i.e. rock slurry and earth).
This approach will nearly half the number of concrete and excavation truck movements to and from the construction site and provide the following tangible benefits (as compared to the alternative whereby the construction program would exclusively rely on mixing trucks for delivery of concrete):
- Reduced traffic congestion
- Reduced safety risks due to higher traffic volumes
- Reduced noise from truck deliveries and higher traffic volume
- Reduced exhaust from construction traffic
- Reduced dust from concrete mixing.
6. Is there other construction in the airport’s immediate area?
The City of Toronto and Waterfront Toronto are making improvements to the water’s edge. Waterfront Toronto will be building the first phase of a promenade on the east side of the Canada Malting Silos (i.e. the Portland Slip). Waterfront Toronto’s construction staging area is on the Canada Malting Silos lands, immediately south of the Waterfront and City Schools and the Harbourfront Community Centre.