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Underwater construction


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Brief information about Underwater constructions

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Underwater construction

  2. 2. what is underwater construction?
  3. 3. introduction • during the construction of bridges, dams or any other structure where the foundation part of the structure is most likely to lie underwater, we have to opt for underwater construction • construction in water poses many difficulties especially in the places where there the depth is considerable
  4. 4. activities include • power generation • bridges
  5. 5. • water utilities • ship husbandry
  6. 6. • industrial mining pipeline • power and gas transmission
  7. 7. underwater construction techniques almost any construction technique that can be used abovewater can also be used underwater
  8. 8. underwater construction techniques There are a number of products and materials that have been formulated or developed specifically for underwater work
  9. 9. underwater construction techniques •wet construction & •dry construction
  10. 10. wet construction • a diver • evaluate the overall cost of the work • considering time • equipment needs • the capability of a diver to accomplish the specific task • a more gross than fine nature
  11. 11. dry construction caisson & cofferdam
  12. 12. caisson •permanent structure •large hollow structure that sunk down through the earth • used in construction of bridge piers, building columns, dams, repair of ships... •keeps working environment dry
  13. 13. working area of caissons
  14. 14. advantages of caisson •economic •slight less noise and reduced vibrations •easily adaptable to varying site conditions •high axial and lateral loading capacity
  15. 15. cofferdams • temporary structure • allows enclosed space to be pumped out, creating dry environment • enclosed coffers are commonly used for construction and repair of oil platforms , bridge piers and other support structures built within or over water • a cofferdam involves the interaction of the structure, soil and water. Loads imposed include the hydrostatic forces of the water as well as the dynamic forces due to currents and waves • used for shallow construction having depth less than 10m.
  16. 16. working area of cofferdams
  17. 17. advantages of cofferdam • provides safe environment to work • contractors have design responsibilty • steel sheet piles are easily installed and removed • materials typically reused on other projects
  18. 18. placing concrete under water The satisfactory method of placing concrete underwater is by the use of tremie pipe • a tremie is a water tight pipe • generally 250 mm in diameter • capable of easy coupling for increase or decrease of length • Funnel shaped hopper at its upper end and a loose plug at the bottom • the concrete having a very high slump of about 15 to 20 cm is poured into the funnel tremie method
  19. 19. placing concrete under water tremie method • lifted up and slight jerk is given, so that the concrete gets discharged • again concrete is poured over the funnel, the pipe is slightly lifted amd given jerk • in this way concrete work is progressed without stopping till the concrete level comes above the water level
  20. 20. placing concrete under water
  21. 21. -pranay kumar (CVSR colg. of engg.)