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MEGA PROJECTS
An immersed tunnel will also
present considerable technical
challenges. However, unlike a bridge,
an immersed tunnel will not entail as
many technical operations which push
the limits of what has been done before.
Essentially, the procedure will be the
same as it was for construction of the
Øresund Fixed Link’s immersed tunnel
under the Drogden Channel between
Denmark and Sweden, only many times
longer and deeper. The Fehmarnbelt
Tunnel will be just under 18km long and
up to 30-40m deep, while the Øresund
Tunnel is approximately 4km long and
about 10m deep.
Both a cable-stayed bridge and
an immersed tunnel would impact the
marine environment but the preliminary
conclusion is that a bridge would have
slightly more significant permanent
impact than an immersed tunnel.
In the interests of navigation safety,
a tunnel poses fewer risks than a
bridge. The Fehmarnbelt is a heavily
trafficked stretch of water with 47,000
vessel transits per annum (2006). In
the coming years, traffic is expected to
increase substantially to about 90,000
vessel transits in 2030.
Financial factors
In financial terms, there is very little
difference between the two projects.
The construction estimate (in 2008
price level) for an immersed tunnel is
E5.1 billion and for a cable-stayed
bridge, E5.2 billion.
The construction time for the
tunnel is estimated at 6½ years, and
for the bridge, 6 years. The cost of
operation and maintenance is slightly
higher for a tunnel than for a bridge.
All told, the payback time for the two
projects would be essentially the same
at about 30 years for the coast-tocoast
project. In a press release of the
announcement, Danish Minister for
Transport Hans Chr. Schmidt stated:
“From an overall financial perspective,
there is no difference between bridge
and tunnel. The cost of the two
solutions is, generally speaking, the
same, which confirms the project’s
sound financial basis.”
Over the coming year, Femern
A/S will complete the Environmental
Impact Statement to be considered
by the authorities in Denmark and
Germany in accordance with national
regulations and submit an application
for construction approval to German
authorities during the first six months
of 2012. A construction bill will then
be submitted to the Danish Parliament,
Folketinget, in 2013. Following
approvals, construction of one of
Europe’s biggest infrastructure projects
is expected to commence in 2014 and
open to traffic in 2020. •
Innovations for the
In September 2008, the Danish and
German Ministers of Transport signed
a treaty to establish a link across the
Fehmarnbelt between Lolland, Denmark
and Fehmarn, Germany. The same treaty
was subsequently approved by the Danish
Parliament and the German Bundestag.
The Fehmarnbelt Fixed Link will be the
third major crossing in Denmark after
realization of the Great Belt (1998) and
the Øresund (2000) links. It represents the
missing link in an efficient transport corridor
between Scandinavia and Europe and will
accommodate a four-lane motorway and a
double track railway (Fig 1).
Denmark has assumed sole
responsibility for the financing,
implementation and future operation of the
fixed road and rail link and for this purpose
the state owned organization Femern A/S
has been established. A feasibility study in
1996-1999 looked into a great number of
possible solutions, including bridge and
tunnel (immersed and bored) options, train
shuttles, double and four lane motorways,
single and double track rail, integrated or
seperated from the motorway. On the basis
of the study it was decided to construct
a four-lane motorway and a double track
railway. A cable-stayed bridge was favoured
and the Danish and German Governments
labelled this as the preferred solution.
However, it was decided that an immersed
tube tunnel alternative for the entire crossing
had to be investigated during the planning
stage. Variants which combine in-line or
parallel bridge-tunnel combinations were
not considered due to the great waterdepth,
which would require a huge reclamation to
connect the bridge and tunnel for the in
line option; and for economical reasons for
the parallel arrangement. The final decision
between either a bridge or a tunnel was to
be taken only after it had become clear that
both options were technically feasible and
necessary approvals could be obtained.
In April 2009, Femern A/S selected the
Rambøll-Arup-TEC JV for the design of the
tunnel alternative.
The immersed tunnel solution will set
new records in terms of its dimensions; it
will be the longest tunnel and one of the
deepest tunnels of this type ever built with
a length of 20km and foundation depths
reaching more than 40m under the sea
surface. The size of the project will create
major challenges for designers and future
contractors and will allow for an innovative
approach based on proven technology.
If constructed, the immersed tunnel, will
also be the world’s longest combined road
and rail tunnel; the world’s longest under
water tunnel for road; and the deepest
immersed tunnel with road and rail traffic.
The size of the project is about five times
the tunnel part of the Øresund Link between
Denmark and Sweden and will require a
huge logistical and qualitative challenge
to build in the available construction time
of approximately six years. The amount of
material to be dredged for the trench is about
20 million m 3 and the amount of concrete
for the immersed tube elements is about 3
million m 3 . Production of the elements would
require four to five construction facilities as
used for the Øresund Link.
Operational safety in a tunnel of this
length is a challenge and requires careful
PREVIEW
References
• Fehmarnbelt fixed link options -
TunnelTalk, June 2009
• Cost comparison for Fehmarnbelt link
options - TunnelTalk, Nov 2010
Fig 1. Integration of the road and rail Fehmarnbelt fixed link
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TunnelTalk ANNUAL REVIEW 2010
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