ARTIFICIAL ISLANDSARTIFICIAL ISLANDS

PRESENTED BY:SHARANG AGARWAL (11NA30019)

AJIT KUMAR (11NA30024)

THE EARTH PLANET

Percentage of crustal, About70% water30% land

From 30% land also there are some barren spaces. Like mires.

People motivate to get benefits from the water areas.

IntroductionAn artificial or man-made  island is an island or group  of  islands  that  has  been constructed by people rather than formed by natural means.

Methods of Creation1.Expanding existing islets2.Construction on existing reefs3.Amalgamating several natural islets into a bigger island.4.Construction on sea bed.5.Land Reclamation6.Oil Platforms 

ReasonsReasons for Construction for ConstructionThe following are the major reasons to justify the creation of Artificial Islands:

- urban development (special structures)

- industry

- waste handling

- infrastructure (ports and airports)

- extended runways

- recreation

- mining of natural resources

- oil drills and exploration platforms.

- tidal or wind energy generation.

- recreational structures like hotels or water parks.

Previous UsagePrevious Usage1)  Artificial  islands  have  been  used  since  the  seventeenth century  for  coastal  defence  and  as  extensions  of  the  land base.

2)  Artificial  islands  are  being  used  as  oil  exploration  and production platforms.

3) Japan has several artificial islands.  

4) Artificial islands are being used to provide a platform for coal mine  ventilation  shaft  access,  positively  contributes  to the safety, effective ventilation and reserves of a coal mine.

5) Technology of artificial island construction is available to construct islands in water depths of 70 m.

6) Artificial  islands  become  a  focus  for  sea  life,  enhancing the marine environment.

Under the United Nations Convention on the Law of the Under the United Nations Convention on the Law of the Sea treaty  (UNCLOS),  artificial  islands  are  not Sea treaty  (UNCLOS),  artificial  islands  are  not considered harbour works and are under the jurisdiction considered harbour works and are under the jurisdiction of  the  nearest  coastal  state  if within  200  nautical miles of  the  nearest  coastal  state  if within  200  nautical miles (370 km) .Artificial islands are not considered islands for (370 km) .Artificial islands are not considered islands for purposes  of  having  their  own  territorial  waters  or purposes  of  having  their  own  territorial  waters  or exclusive economic zones, and only the coastal state may exclusive economic zones, and only the coastal state may authorize  their  construction. However,  on  the  high  seas authorize  their  construction. However,  on  the  high  seas beyond  national  jurisdiction,  any  "state" may  construct beyond  national  jurisdiction,  any  "state" may  construct artificial islands .artificial islands .

Political Status

Design Design ConsiderationsConsiderations water depth  wave height range climate ice conditions tidal range currents foundation conditions earthquake risk source of materials shipping lanes existing pipelines and cables legal aspects environmental considerations fisheries considerations

LOADS IMPOSED IN DESIGN Permanent loads

Variable loads

Environmental loads

Permanent loads1.The weight in air of the structure and superstructures calculated from nominal values of dimensions and mean values of densities.2.Equipment which cannot be removed3.Hydrostatic external pressure and buoyancy in calm sea conditions calculated for mean sea level.4.Ballast including ballast water pressure5.Permanent earth pressure

Variable Loads1.Weight of equipments, materials and stores which may be removed after the phase considered.2.Variations in internal and external pressure from water,oil,gas,etc. caused by normal operating of the structure.3.Loads due to fendering and mooring of vessels, helicopter landing, cranes or drilling operations.

Environmental Loads 1.Wind 2.Weather loads due to heating and cooling.3.Sea loads like wave loads, tidal loads, currents etc.4.Earthquake and tsunami loads.

This islands constructed are technically, artificial peninsulas of sand dredged from the bottom of the sea.

The sand is sprayed by the dredging ships, which are guided by GPS, onto the required area in a process known as rain bowing.

CONSTRUCTION OF THE ISLAND

Sand surcharge

Clay lumps

Inter-lump voids Filled water

Mean sea level

Seabed

UNDERGROUND CONSTRUCTION & SEA BED DREDGING

Place the material in the form of lumps, directly at the reclamation site

Sand is siphoned up from the ocean floor, being deposited in one of the hoppers of the Dredge Island

CONSTRUCTION PROCEDURE

Temporary tube piles driven into sea bedTemporary sheet piles and tie rods driven into sea bed

to support boundary rocks (see figure 1)

Permanent boundary rock is constructed like bunds & it deposited either side of sheet piles

Hydraulic fill layers deposited between bunds to displace sea water and form island (see figure 2)

Permanent concrete units are placed around island to protect it from the waves

2m diameter 43m deep piles driven through island into the below of the sea bed to stabilize structure (see figure 3)

Island interior excavated and temporary sheet piles or coffer dam inserted

2m thick concrete plug slab laid at base of islandReinforced concrete retaining wall builtBasement floors created (see figure 4)

FINALIZED RECLAMATION ISLAND

This island includeHomes HotelsOfficesAgricultural lands

Protection of Artificial Islands

BREAKWATER CONSTRUCTIONBreakwater : A structure which breaks the force of the

waves, it is constructed close to the island and acts as a

protection against strong currents and winds.

The breakwater is constructed using multiple layers of sand, a

water permeable sheet, small rocks, and layers of armour rocks

The breakwater should be constructed of rock rather than

concrete to encourage the creation of an artificial reef.

Two openings in the breakwater were created in order to

prevent the water inside from stagnating.

BREAKWATER

IMAGE : PALM JUMERIAH , DUBAI

FAMOUS ARTIFICIAL ISLANDS

THE WORLD- DUBAI

PALM ISLANDS - DUBAI

KANSAI AIRPORT, JAPAN

BURJ KHALIFA HOTEL, DUBAI

PROBLEMS AND CHALLANGES1. Excessive cost involved in construction2. Slow construction process due to limited availability

of dredgers.3. Environmental impact due to removal and placement

of sand. Though it can be prevented through shallow cuts.

4. Settlement of the island in deep waters, as in the case of kansai airport, Japan

5. Excessive exposure to winds, tidal forces, earthquake and tsunami loads. Thus special provisions are required.

ADVANTAGE : ANY SHAPE, ANY SIZE, ANYWHERE.

REFERENCES

1.Construction of offshore structures – Ben C. Gerwick – John Wiley and sons2.ARTIFICIAL SAND FILLS IN WATER – Centre for civil engineering research and codes - A.A.BALKEMA/ROTTERDAM/BROOKEFIELD.3.Case Study : Burj Al Arab, Dubai4.Man Made Land Features : The Palm Jumeriah and Dubai’s Artificial Islands : Terry Austin.