Toronto Island Airport Adds Underwater Pedestrian Tunnel

PortsToronto has gone to great lengths - and depths - to provide passengers with better access to Billy Bishop Toronto City Airport (YTZ) by building an underwater pedestrian tunnel between the island airport and Canada's largest city. Airport officials call the walkway a "game-changer for operations and customer service" and consider it YTZ's new primary access route. 

From an architectural and engineering standpoint, the 850-foot-long tunnel is a rare piece of infrastructure with few others like it in the world.   
 

facts&figures Project: Underwater Pedestrian Tunnel Location: Billy Bishop Toronto City Airport  Airport Authority: PortsToronto Tunnel Size: 853 ft. long Depth: 100 ft. Cost: $82.5 million Funding: Airport improvement fees Duration of Construction: 36 months Business Model: Public-Private Partnership  Lead Developer: Forum Equity Partners Lead Designer: Arup  Architecture & Interior Design Subcontractor: ZAS Architects Design-Builder: PCL Constructors Canada  Tunnel Subcontractor: Technicore Underground Facility Manager: Johnson Controls  Renewable Energy Provider: Bullfrog Power Opened: July 2015 Concrete Poured to Create Tunnel Liner: 200 cubic meters  Accolades: Int'l Tunnelling & Underground Space Association's 2014 Specialist Tunnelling Project of the Year Award; Tunnelling Association of Canada's 2014 Canadian Project of the Year Award

Previously accessible only by ferry, YTZ opened the $82.5 million underground tunnel in late July 2015. Now, pedestrians can travel to and from the aviation gateway 100 feet below Lake Ontario at their leisure, rather than riding the traditional - and ongoing - ferry that services the airport at 15-minute intervals.  

To access the tunnel from the city side, pedestrians descend one of six elevator banks 10 stories in about 30 seconds. Once underground, they can ride a moving sidewalk that travels at a pace of 2.3 kilometers per hour or traverse the stationary path between the two sets of moving sidewalks for 550 feet to the south end of the tunnel. From there, travelers can climb 153 steps, take an elevator, or ascend into the airport's check-in area via one of the longest escalator systems in Canada. A full-size replica of the World War I fighter plane flown by the airport's namesake hangs in the glass-walled atrium at the top of the escalators.  

Predicated Need

With more than 2.4 million passengers traveling through the airport each year, YTZ is a significant economic driver for the city of Toronto. "The success of this airport, as measured against economic achievement, customer satisfaction and industry awards, predicated the need for improved access to and from the mainland," says Geoffrey Wilson, chief executive officer of PortsToronto, the government business enterprise that owns and operates YTZ.

"We wanted to provide our passengers with convenient, predictable and reliable access to Billy Bishop Airport, and enable passengers to travel on their own schedule from the mainland to the airport," Wilson explains. "The tunnel achieves this, allowing passengers to get from the curb to their check-in counter in approximately six minutes."

The new tunnel is also a key component of the port authority's overall traffic management strategy, because it improves the flow of passengers by alleviating congestion at the airport caused by concentrated waves of travelers arriving and departing according to the ferry schedule. A more steady flow of passengers reduces queuing inside the terminal, especially in areas such as ticketing and security, explain officials. 

Although the ferry takes only 11/2 minutes to cross the channel, it can carry only 200 passengers at a time. Previously, passengers had to wait for the next trip when the ferry was full. These days, they can travel through the tunnel, any time of day. And the tunnel can accommodate up to 1,100 people per hour. 

Public-Private Partnership

PortsToronto procured the tunnel via a public-private partnership (P3), structuring the initiative as a design-build-finance-maintain project. Forum Equity Partners acted as lead developer, with PCL Constructors Canada as design-builder, Arup as lead designer, Technicore Underground as tunnel subcontractor and Johnson Controls serving as facility manager.

The highly complex engineering feat is the first public-private partnership project undertaken by a Canadian port authority, notes Wilson. "It was through the P3 model that we were able to innovatively design and finance the project, resulting in the tunnel being delivered on time and on budget, at no cost to taxpayers - no small accomplishment for a popular and growing airport, and something of which we are very proud," he remarks. The project was funded by airport improvement fees ($20 per trip, paid by departing passengers).   

Throughout the P3 project, YTZ's operations team worked closely with the tunnel's development team on way-finding initiatives. It also helped schedule work to minimize impact on airport operations and the surrounding community.

"The completion of the ... tunnel is a sterling example of what can be accomplished when the public and private sector work together," says Richard Abboud, founder and chief executive officer of Forum Equity Partners. "The framework utilized by PortsToronto provided significant advantages through the design, build, finance and maintenance phases of the tunnel project. It enabled us to successfully leverage innovations offered by the private sector and to reduce the upfront funding requirements for the project."

In its role as design-builder, PCL worked collaboratively with all parties to attain the most innovative design solution possible to reduce the cost of the overall project and maximize value for PortsToronto, notes PCL Vice President and District Manager Bruce Sonnenberg. 

"The design solution PCL settled upon with Arup and Technicore used an innovative approach to supporting the tunnel crown by drilling seven 1.85-meter diameter interlocking drift bores at the tunnel crown using compact tunnel boring machines. The drifts allowed excavation to continue under the crown, while supporting the rock above the tunnel."

In addition to carrying travelers to and from the airport, the new tunnel also acts as a utilities conduit - a private sector measure that is estimated to save $10 million in duplicate construction costs. Running much-needed city water and sewage mains to Toronto Island via the tunnel was a major advantage facilitated by the P3 structure of the project, note PortsToronto officials. Other highlighted features include custom material handling equipment that was able to function in the tight spaces and the use of an onsite cement batch plant to minimize construction traffic and congestion.

"Constructing a tunnel of this scale and complexity 100 feet under Lake Ontario while maintaining efficient operation of a busy airport was no easy feat, but we proved we were up to the challenge every step of the way," reflects Ken Lundy, vice president of Infrastructure, Planning & Environment for PortsToronto. 

The project was delivered on budget and within the 36-month timeframe announced for the project in 2012, adds Lundy. Delays prior to the 2012 mark that are largely associated with changes in Toronto's political administration created public perception that the tunnel was finished late when it did not open in time to accommodate travelers in town for the Pan Am Games July 10 to 25. Some frustrated with the pace date original plans for the project back to the 1930s. 

Experiential Awareness

Within PortsToronto, the overreaching goal of the project was to design and build a tunnel that puts the traveler experience first. "A number of the tunnels I've been through have been narrow and dark, with low ceilings," Lundy explains. "But our award-winning tunnel was designed with the passenger experience in mind, with a tall ceiling, wide walkway and lots of light." (See Page 63 for list of awards.)

Feedback from travelers about the tunnel's design and efficiency has been fantastic, he reports. An editorial in the Toronto Star described it as "clean and spacious" and dubbed the underground walkway a "win for travelers and the city." The review cheered the introduction of a "more reliable way to cross over to the airport," which it calls a "major urban asset." A separate article referred to the tunnel as a "sleek and speedy new option" for arriving passengers headed to the mainland.

Columnist Heather Mallick, however, was brutal in her evaluation. One of her objections to the design was its lack of literal, some would say cliché', Canadian references. "Why isn't the tunnel coated in red and white to reflect our flag? Why isn't it blasting maple leaves?" Mallick asked incredulously.

Just days before Mallick's scathing review ran in the Star, a senior principal from ZAS Architects, the architecture and interior design subcontractor for the project, explained the creative team's intentions to The Globe and Mail. "We wanted to keep the design through the tunnel really simple," said Paul Stevens. The splashes of yellows and blues used inside the structure are "notional gestures to the water above and the sun above that," he elaborated.

A series of 42 large Gridcast digital screens installed throughout the tunnel, city-side pavilion and island-side atrium provide advertising and travel-related content. 

"From design to construction to final finishes, this tunnel exemplifies innovation and reflects the priorities of travelers," Lundy reflects. "Whether it be the number of moving walkways and escalators, the acoustics and shape of the tunnel's interior, or the state-of-the-art digital screens that create a visual experience as people move through the tunnel, every detail of the project was carefully thought out to ensure a tunnel that would not only deliver travelers to where they needed to go, but would also engage them along the way."

Arup's Senior Project Manager Ulrike Rennemueller says she is most proud of the pedestrian tunnel's engineering excellence. "I really love when I go to the tunnel and people walking by me say it feels like a natural extension of the airport," says Rennemueller. "Passengers say it's the way an airport should be, and it makes me really proud that people prefer walking over using the ferry." 

Lundy reports that the tunnel had an immediate positive impact on the efficiency of traveler access when it opened last summer. And he fully expects the benefits to endure: "Over the long-term, it will continue to serve as an example of Toronto innovation at its best - something the whole city can be proud of."