This document discusses various methods for underwater construction. It describes wet construction using water tight retaining structures like caissons and cofferdams to create dry environments for building bridge piers, buildings, and dams. It also discusses the challenges of underwater construction when water depths increase and the objectives of maintaining structural stability. Furthermore, it outlines techniques for underwater concreting using tremie pipes, pumps, and toggle bags to place concrete below the water surface.

1. UNDERWATER
CONSTRUCTION

2. Construction that happens under water.
Mainly foundation of bridges, dams etc require
underwater constructions.
Has many difficulties when the water depth is
considerable.
Main objective-to create dry and water free
environment for working to attain structural stability.
Introduction

4. Wet Construction

6. ❏ water tight retaining structure.
❏ permanent in nature.
❏ used in construction of bridge piers, building
columns, dams, etc.
❏ constructed in a way that the water can be pumped
out.
CAISSONS

8. ❏ economic, less noise and reduced vibrations.
❏ adaptable to varying site conditions.
❏ high axial and lateral loading capacity.
❏ placement is possible where pile driving is not
possible.
ADVANTAGES

9. ❏ It is so named since it appeared in construction
workers when they left the compressed atmosphere
of the caisson and re-entered the normal atmospheric
conditions.
❏ Construction of the Brooklyn Bridge, which was
built with the help of caissons, resulted in numerous
workers being either killed or permanently injured
by caisson disease during its construction, including
the designer’s son and Chief Engineer of the project.
CAISSON DISEASE

10. ❏ temporary structure, built within or in pairs across a
body of water.
❏ allows enclosed space to be pumped out.
❏ enclosed coffers are used for construction and repair
of oil platforms, bridge piers and other support
structures within or over water.
COFFERDAMS

11. ❏ involves the interaction of the structure , soil and
water.
❏ the loads imposed includes the hydrostatic forces and
the dynamic forces due to currents and waves.
❏ used for shallow constructions having depth less than
10m.
Contd….

13. ❏ allow construction and excavation in poor
environment.
❏ provides safe environment to work.
❏ sheet piles can easily be installed and removed.
❏ materials can typically be reused on other projects
ADVANTAGES

14. It is the process in which the prepared concrete is
poured below the water surface by using suitable
methods.
PLACEMENT METHODS
• tremie method
• pump method
• toggle bags
UNDERWATER CONCRETING

15. ❏ Watertight pipe generally with 250mm diameter.
❏ has a funnel shaped hopper at its top and a loose plug
at the bottom.
❏ supported on a working platform above water level.
❏ lower end of the pipe is kept immersed in fresh
concrete.
TREMIE METHOD

17. ❏ Pumping concrete directly into its final position,
involving both horizontal and vertical delivery of
concrete.
❏ operational efficiency with potential savings of time
and labour.
❏ for massive underwater concrete construction of
navigation structures, the method is prohibited.
PUMP METHOD

19. ❏ Used for the placement of small amounts of
concrete.
❏ bag is filled in dry condition with wet concrete.
❏ used mainly for repairing works.
❏ concrete is squeezed out from the bag by the diver.
TOGGLE BAGS

21. ❏ Most luxurious of the underwater hotels.
❏ currently being constructed for the past 13 years and
it is promised to be opened within couple of years.
❏ it is 40feet under the sea in an offshore lagoon.
❏ resort is set to house 25 suites, a restaurant, bar, and
even a wedding chapel.
POSEIDON UNDERSEA RESORT- KATAFINGA
ISLAND , FIJI

25. ❏ Located in the Persian gulf between the Burj al Arab
and the Palm Jumeirah islands.
❏ proposed by the polish architect Krysztof Kotala.
❏ sports arena will also double up as an aquarium with
a rooftop coral reef which will put on display an
abundance of sea life for spectators as well as for
players.
LATEST UNDERWATER TENNIS COURT
DUBAI

27. ❏ Cofferdams are used in cases where the plan area of
the foundation is very large, depth of water is less
and for soft soils.
❏ Caissons becomes economical in cases where the
plan are of foundation is small, large depth of water
and for loose soil.
❏ Tremie placement method is the standard way of
placing high quality concrete under water.
CONCLUSION

28. Submitted by,
Hamsui Harold
&
Sharu Tany Prasad

29. THANK YOU…