GTA Construction Report staff writer
‘Chip’, one of the two tunnel boring machines being used to construct the $82.5 million pedestrian walkway to Billy Bishop Toronto City Airport, has completed one of the drift tunnels and broken through the tunnel’s shaft wall on Toronto Island.
The Canadian-made tunnel boring machine was lowered into the tunnel shaft at the foot of Eireann Quay on January 10 and began drilling on January 12. Its twin, ‘Dale’, is currently beneath the Western Gap creating one of seven drift tunnels that will form the walkway’s crown. ‘Chip’ will be returned to the mainland to begin work on the next drift tunnel, says a news release issued by the Toronto Port Authority (TPA).
The walkway crown will be arched and comprise seven smaller, interlocking tunnels (six feet/1.8 metres) designed to reduce the potential for water ingress during construction. These tunnels will be constructed to form an arched roof for the walkway. Three of the drift tunnels will carry city mains to the Toronto Islands.
The TPA is building a pedestrian walkway across the Western Gap to Billy Bishop Toronto City Airport. The 800-foot walkway will be completed in spring 2014 and will be the only known pedestrian tunnel in the world that connects to an airport and sits beneath a body of water.
The tunnel project is being delivered 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).
The project’s key milestones include:
- ·Start of construction – March 2012
- ·Completion of the relocation of underground services – May 2012
- ·Completion of excavation of the tunnel’s shafts – October 2012
- ·Completion of the excavation of the tunnel – April 2013
- ·Completion of new mainland pavilion – January 2014
- ·Completion of project – April 2014