As we wind down our 20th anniversary year at TBM: Tunnel Business Magazine – and look forward to our 21st – we can reflect on yet another momentous year for tunneling both here in North America and worldwide. In fact, the International Tunnelling Association (ITA) reports that the average annual growth of tunneling worldwide is 7 percent – twice that of the global construction rate. Based on ITA data, the yearly average of constructed tunnels is 3,200 miles, with expenditures in excess of $100 billion dollars in 2016.
In North America, the tunneling industry is certainly on the upswing. There are major rail and transit projects with underground components in the planning or design stages across the continent. The list includes the usual suspects – New York, Los Angeles – but also Dallas, San Jose, Calgary and Minneapolis. Demand is also high for sewer, water and highway tunnels.
A quick look at some of the projects that may be coming out over the next decade includes several multi-billion projects, including: California WaterFix (shafts/tunnels >$7 billion), BART 2nd Transbay Tube ($12-15 billion); BART Silicon Valley Santa Clara Extension (~$4.7 billion); Northeast Corridor Superconducting Maglev (~$10 billion); Baltimore B&P Tunnel (~$4.5 billion); NY-NJ Gateway Tunnel (~$12-13 billion for tunnel and related structures); NY Second Avenue Subway Phase 2 (~$6 billion); and the Hampton Roads Bridge-Tunnel (~$3.3 billion).
Combined with “smaller” tunnel projects and programs throughout the continent, the future looks promising.
It is interesting to see in the wake of SR 99 project in Seattle, that agencies are not shying away from large diameter TBMs for urban projects. Of course, Bertha – the SR 99 TBM – performed as expected after a long and costly delay due to a mechanical failure, so perhaps it is being viewed as a success story.
Notably, the Santa Clara Valley Transportation Authority (VTA) and the Bay Area Rapid Transit (BART) in April approved a plan to proceed with a single-bore tunnel as part of its expansion project into San Jose. Planners were deciding between using a large single bore or more traditional twin-bore tunnels under San Jose.
The single-bore proposed for San Jose would use one 45-ft diameter tunnel boring machine (TBM) to construct a 5-mile long circular tunnel structure. The boarding platforms will be constructed one above the other inside the tunnel bore without construction disruption at the surface. This would be the first use of a large-bore TBM tunnel for a subway project in North America.
In Calgary, planners are embracing a similar approach to the Green Line project, using a large-diameter TBM to construct 2.5 miles of tunnel downtown. Project manager Paul Giannelia told the Calgary Herald that the single bore option could reduce disruption as well as cost.
To the east, two new highway tunnels will be using large diameter tunnels in place of immersed tube tunneling that had been the most prominent method in the past. Dragados/Schiavone will be using a 42-ft Herrenknecht TBM to bore the 1-mile Chesapeake Bay Bridge-Tunnel, while in the Hampton Roads area, the Virginia Department of Transportation selected the bored method over immersed tube. The project is currently in the bidding phase.
There were plenty of other developments and exciting projects happening in 2018. We look forward to bringing you all the coverage of the North American market in 2019 and beyond!
Jim Rush, Editor/Publisher