This document discusses underwater construction techniques. It describes caissons and cofferdams which are used to create dry work environments for underwater foundations. Caissons are watertight retaining structures that can be pumped out to stay dry, while cofferdams are temporary structures built to block water flow. The document also discusses underwater concreting methods like the tremie method and pump method. Finally, it provides examples of structures built using these techniques like bridges, dams, offshore oil platforms, and proposes some future underwater structures like hotels and tunnels.

1. UNDERWATER CONSTRUCTION
P.NAVEENA PRIYADARSHINI
ROLL NO:2451-14-732-077
B.AISHWARYA
ROLL NO:2451-14-732-093
CIVIL ENGINEERING
MVSR ENGINEERING COLLEGE

2. INTRODUCTION:
During construction of bridges , dams and other structures
where foundation part is laid underwater mostly , we have
to opt for underwater construction.
Our main object is to create a dry surrounding for working
such that there will be a structural ability during dry
process.
This includes various process as following:-
 1. construction techniques
 2. Underwater concreting

3. CONSTRUCTION TECHNIQES:
1.CAISSONS :
 Watertight retaining structure.
 Constructed such that water can be
pumped out.
 Keeps working environment dry.
Types of caissons:
1. open caisson
2. box caisson
3.suction caisson

4. 2.COFFER DAMS:
Temporary structure.
Built across body of water.
Involves interaction of
structure , soil and water.
Creates a dry work
environment.
Components :-
1. sheet piling
2. brace piling
3. concrete seal

5. UNDERWATER CONCRETING:
Prepared concrete is poured below the water surface by
using suitable methods:-
1.TREMIE METHOD:

6. 2.PUMP METHOD:
Ideal for small
amounts of concrete
placement.
The concrete is
squeezed out by a diver.
Bags are usually of 10
to 20 litres capacity.
3.TODDLE BAGS AND BAG
WORK:

7. MACHINERY
Builders have been making their marks on the other
two-thirds of the planet.
 These four underwater construction techniques
changed the world we live in.
I. Pneumatic caissons
II. Suction dredgers
III. Immersed tube tunnels
IV. Offshore oil drilling

8. 1.PNEUMATIC CAISSONS 2.SUCTION DREDGERS
Piers at The Eads Bridge, St
Louis, MO
The Geopostes 15 Suction
Dredger, from Vanoord .

9. 3.IMMERSED TUBE
TUNNEL
Cross segment from the Elizabeth
River Tunnels, Portsmouth and
Norfolk, Va.
Oil Platform, Brazil P-51, Brazil.
4.OFFFSHORE OIL DRILLING

10. SOME OF THE STRUCTURES BUILT
TIDAL WINDMILLS:

11. OPERATION OF WINDMILL:
In simple a underwater windmill consists of a number of
blades mounted on a hub (together known as the rotor), a
gearbox, and a generator.
The hydrodynamic effect of the flowing water past the
blades causes the rotor to rotate, thus turning the generator
to which the rotor is connected via a gearbox.
The gearbox is used to convert the rotational speed of the
rotor shaft to the desired output speed of the generator
shaft.
The electricity generated is transmitted to land through
cables.

12. PROPOSED UNDERWATER HOTELS
HYDROPOLIS HOTEL AND RESORT IN DUBAI

13. UNDERWATER CANCUN
MUSEUM IN MEXICO
PALM ISLANDS

14. UNDERWATER TENNIS COURTUNDERWATER TUNNELS

15.  Cofferdams are temporary structures and used in cases where the plan area
of foundation is very large, depth of water is less and for the soft soils.
Caissons are permanent structures and becomes economical in cases where
the plan area of foundation is small, large depth of water and for loose soils .
 At present, the tremie placement method is the standard way of placing
high-quality concrete underwater.
 Underwater construction is useful for power generation , bridges , ship
husbandry , water utilities , mining , pipe line , power and gas transmission.
 And attracting places for tourists.
CONCLUSION:

16. QUERIES?

17. Where god forgot to build a way we made it.
Thank you.