Norway’s $47BN Coastal Highway | The B1M

Norway’s $47BN Coastal Highway | The B1M

October 14, 2019 100 By Luis Garrison


The western coast of Norway is home to some
of the most dramatic landscapes on earth. Carved by glaciers throughout the ages, some
of these fjords stretch for 200 kilometres inland and are over a kilometre deep. The current convoluted travel route through
and around this terrain takes you along Norway’s 1,100 kilometre, 683 mile, E39 highway. A road with a total journey time of 21 hours. Now, the Norwegian government are working
to improve access to services and residential and labour markets across the country’s
western regions by embarking on the largest infrastructure project in the nation’s history. Norway’s E39 highway runs between, Kristiansand in the far south of the country and Trondheim
in the north. The route navigates its way across the fjord network and features no fewer
than seven ferry crossings. The new coastal highway project aims to eliminate
the need for ferry services altogether by building a series of bridges and tunnels across,
through and under the landscape. With many of the fjords along the route being
too wide or too deep for conventional infrastructure to cross, innovative new solutions are being investigated by the Norwegian Public Roads Administration. Rogfast is the first in a series of crossings
that will link the E39, connecting Stavanger and Haugesund via a 27 kilometre, 16 mile,
under sea tunnel. This structure will reach depths of up to
390 metres below sea level, making it the deepest as well as the longest undersea road
tunnel in the world. The Rogfast project will in fact consist of
two tunnels connected every 250 metres with emergency exits. Each tunnel will have a lay-by
at 500 metre intervals, along with telephone and surveillance cameras along the route. The tunnel will also feature a mid-route intersection
with the island municipality of Kvitsøy creating an undersea tunnel junction and connecting
the island with the Norwegian mainland. With work begun in 2018, this element of the
project is set to be completed by 2026 at a cost of USD $2BN. While the Rogfast works are already underway,
the scale of some other fjords is presenting the project team with extreme engineering
challenges. Bjornafjord – located to the south of Bergen
– stands 5 kilometres wide, and reaches depths of 600 metres. To cross this challenging stretch of water,
a proposal has been put forward for a floating bridge, anchored to the shore at both ends. The Sulafjord crossing has seen two possible
solutions put forward. The first is for a three tower suspension
bridge, with two of the bridges’ towers anchored on land and the third central tower
anchored to the seafloor, some 400 metres below the water line. An alternative proposal for a “submerged
floating tunnel” would see two interconnected tubes running side by side tethered to the
seabed using high strength cables. Crossing the Romsdalsfjord will require a
16 kilometre undersea tunnel, much like the Rogfast project, from Alesund to Midsund – followed
by a 2 kilometre suspension bridge connecting onto Molde. By far the most complex and ambitious of all
of the coastal highway crossings is that at Sognefjord – also known as the “King of
the Fjords”. Norway’s largest and deepest fjord is over
3.7 kilometres wide and an incredible 1.3 kilometres deep at its lowest point. While these extreme distances pose their own
challenges, engineers must also account for the high number of ships that enter the fjord
on a regular basis. Any crossing must allow for a clear shipping
lane that is at least 400 metres wide – with 70 metres clearance above the water’s surface
and at least 20 metres clearance into the depths. To deliver this, the project team are considering
numerous different types of crossing for this fjord. The first is a traditional suspension bridge.
With a 3,700 metre crossing, such a structure would be almost double the length of the world’s
current longest bridge and would require support towers at least 450 metres tall, significantly
eclipsing the 343m tall Millau Viaduct in France to become the world’s tallest bridge
structure. A floating bridge is also being considered.
However, this structure would need to raise to allow ships to pass and achieving such
a feature in a bridge that is only anchored to each shoreline poses considerable engineering
challenges that are yet to be overcome. In a similar proposal to that found at Sulafjord,
a submerged floating tunnel in also being considered. This proposal would differ slightly to its
counterpart due to the extreme depth of the Sognefjord. Rather than being tethered to
the seabed, the tunnels would be suspended from floating pontoons that would allow ships
to pass overhead. A hybrid proposal is also being considered
– combining a floating pontoon bridge with a portion of submerged floating tunnel that
allows ships to pass. Whilst fixed bridges transferring into fixed
tunnels is not an uncommon solution in waterways with high shipping traffic – such as the link
between Denmark and Sweden and the extensive Hong Kong to Macau crossing – combining the
two floating structures in this way would create the world’s first example of such a
solution. Finally, a proposal for a multi-span cable
stayed bridge is under review. This structure would feature four floating pylons tethered to the sea floor rather like oil rigs. With safety and environmental considerations
being of the utmost importance, Norway’s vast coastal highway project is set to become
a new benchmark in engineering capabilities and a model for future infrastructure projects
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