submerged floating tunnel powerpoint presentation,seminar and collective information. Civil engineering technologies.

1. SUBMERGED FLOATING
TUNNEL
Presented by
Shaikh Mohammad Ismail
Chaitanya Bharathi Institute of Technology,
Hyderabad(T.S.), India.

2. CONTENTS
• Introduction
• Need for Submerged Floating Tunnels
• Concept
• Material Used
• Structural Components
• Construction Procedure
• Advantages
• Disadvantages
• Case Study
• Conclusion
• References

3. INTRODUCTION
• It is a kind of innovative traffic structure, which is used to cross
sea, large lakes or deep rivers
• It generally consists of tunnel tube suspended in water, anchor
cables fixing displacement of tunnel, deep water foundations
• Submerged Floating Tunnel (SFT), is also known as
Archimedes Bridge

4. NEED FOR SUBMERGED FLOATING TUNNEL
• A “SFT ” is considered when the depth of the water body is too
deep so that no tunnel or any solid body could sustain the
pressure acting on it at such a deep level
• In that case the tunnel is placed such as about 50-60m from
the sea level.

5. CONCEPT
• It is based on “Archimedes Principle”
• Any object wholly or partially immersed in an fluid, is buoyed
up by a force equal to the weight of the fluid displaced by the
object.
• Ships, submarines, offshore oil rigs etc. work on this principle.
• Research shows that the buoyancy to weight ratio for the
tunnel to float should be less than one and between 0.5 to 0.8

6. MATERIAL USED
• Aluminium
• Foam
• Concrete

7. STRUCTURAL COMPONENTS OF SFT
SFT consists of the following elements
• Tubes
• Tethers
• Pontoons
• Shore connections at the ends of the tunnel

8. TUBE
• provides space for the road and/or railway traffic
• The tubes may be constructed of steel, concrete or a
combination of the two.
• Designed with circular cross-sections, primarily from
hydrodynamic reasons. Other shapes as elliptical, Polygonal.
• Gives space to traffic in one direction and provide escape
possibilities in case of fire

10. TETHERS
• vertical or inclined fixing the tube to the seabed at certain
spacing
• Gravity anchors on the seabed providing support for the tethers
• Vertical tethers gives vertical stiffness, but virtually no
horizontal stiffness. In order to also get horizontal stiffness the
tethers have to be inclined

12. PONTOONS
• Pontoons are mounted on top of the tunnel and “anchoring” it
to the sea surface
• pontoons penetrating the water surface will add vertical
stiffness to the system, but they will not add anything to the
horizontal stiffness.
• other measures then have to be added to give sufficient
horizontal strength and stiffness.

14. SHORE CONNECTIONS
• The connections of the tube to the shore require appropriate interface
elements to couple the flexible water tube with the much more rigid
tunnel bored in the ground.
• This joint should be able to restrain tube movements, without any
unsustainable increase in stresses.

15. CONSTRUCTION PROCEDURE
1. PRECASTING
• Huge tunnel sections are constructed on dry dock.
• The procedure consists same as that of precast construction.
• The panels are transported to their respective places.

16. 2.JOINTS
• After the submersion of different panels in water they are
connected with one another by using the rubber gasket.
• procedure includes trapping of water between the joints and
then removing it afterwards.

17. 3. FOUNDATION
• This is incase of tethers,
• The application consists same as that of in caisson foundation.
• A hollow chamber is penetrated down the sea bed as shown
which evacuates the water trapped inside it by a valve present
on its top surface.

18. 4. ANCHORING OF CABLES
• the cables are anchored to the floating tunnel which will avoid
its movement and will place it firmly in alignment.
• This operation can be carried out by divers.

19. ADVANTAGES
• Allows construction of tunnel in extremely deep water, where
conventional bridges or tunnels are technically difficult or
prohibitively expensive.
• Any type of cross sectional area can be provided since being
prefabricated.
• No obstruction to navigational routes as compared to
conventional bridges since all of the tunnel being placed
underwater.
• Construction activities has less harmful effects on aquatic life.

20. • Vehicular emission can be collected at one end of the tunnel
thus reducing the air pollution.
• No harmful environmental effects such as fog or storm since
the whole structure is covered and is present inside the water.
ADVANTAGES

21. DISADVANTAGES
• Immersed tunnels are often partly exposed (usually with some
rock armor and natural siltation) on the river/seabed, risking a
sunken ship/anchor strike
• Direct contact with water necessitates careful water proofing
design around the joints.
• The segmental approach requires careful design of the
connections, where longitudinal effects and forces must be
transferred across.
• Environmental impact of tube and underwater embankment on
existing channel/sea bed.

22. Norway could build the world's first floating
tunnel
• The west side of Norway is made up of 1,190 fjords, which,
while beautiful, make it very hard to travel along the country's
coastline.
• the Norwegian Public Roads Administration (NPRA) has
proposed the world's first underwater floating tunnel, which
would be submerged in the Norwegian Sea.
• Predicted to cost $25 billion (around £19 million)

23. Currently, the drive from the
southern city of Kristiansand to
Trondheim in the north takes an
excruciating 21 hours and requires
seven ferry crossings.

24. The NPRA is also considering creating a
12,139-foot-long suspension bridge, which
would be three times the length of San
Francisco's Golden Gate bridge and double
the current world record for a bridge's
length.
This solution is reminiscent of the
Oresund which connects the Danish
capital of Copenhagen to the Swedish
capital of Malmö.

25. CONCLUSION
• The submerged floating tunnel will set up new trends in
transportation engineering and which shows with the advances
in technology that will reduce the time required for travelling.
• For wide and deep crossings the submerged floating tunnel
may be the only feasible fix link, replacing present day ferries
and providing local communities with new opportunities for
improved communication and regional development.
• So why has an SFT not been built yet? There may be
reluctance to being the pioneer who builds the first one, in case
something unexpected goes wrong. It may just be that the
concept is not sufficiently known that the possibility exists

26. REFERENCES
S.NO. PAPER AUTHOR ABSTRACT CONCLUSION
1. Immersed and
floating tunnels
Christian
Ingerslev
(2010)
It follows the development of
SFT through ITA Working
Group 11 “Immersed and
Floating Tunnels” that has
resulted in proposed designs
for tunnels in Europe and
where SFT might be used
world-wide.
The concepts of floating bridges
and tethered oil production
platforms have been accepted by
the general public, the concept of
doing the same thing but for an
underwater tunnel has not – yet.
2. Design of the
Submerged
Floating Tunnel
operating under
various
conditions
Bernt
Jakobsen
(2010)
In the Høgsfjord project whose
feasibility was well documented
before the project was stopped
for local political reasons the
length was some 1400 m, the
water depth about 150 m and
the site was well protected from
large sea waves
For deep waters, such as for the
very deep Sognefjorden, other
concepts have been proposed,
Since it is believed that tethers
down to the seabed in such cases
would be very technically
challenging and above all
extremely costly.

27. REFERENCES
S.NO. PAPER AUTHOR ABSTRACT CONCLUSION
3. Challenge in design
and construction of
submerged floating
tunnel and state-of-
art
Yiqiang
Xianga, Ying
Yang
The technological
difficulties and
corresponding solution
were proposed. At last,
the several key problems
to be needed further
research were proposed,
so as to provide
reference for the design,
construction and project
risk analysis of future
SFT.
At present, China doesn’t
have any specifications for
design, construction and
maintenance for SFT. So
compiling a complete set of
specifications based on
theoretical researches is
significant for the application
of SFT.

28. THANK YOU.