23-05-2010, 12:08 AM
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PRESENTATION
ON
CAiSSON
Presente BY
BISWAJIT BORAH
INTRODUCTION
The term caisson is derived from the French word, Caisson meaning a chest or box . Caisson has come to mean a box like structure, round or rectangle, which is sunk from the surface of either land or water t desired depth.
TYPES OF CAISSONS
1) BOX CAISSONS
2) OPEN CAISSONS (WELLS)
3) PNEUMATIC CAISSONS
BOX CAISSONS
A box caisson is open at the top and closed at the bottom and is made of timber, reinforced concrete or steel.
A BOX CAISSON
OPEN CAISSON
An open caisson is a box of timber,metal, reinforced concrete or masonary which is open both at the top and the bottom, and is used for building and brige foundations. Pen caissons are called wells.
SHAPE OF WELLS
SINGLE CIRCULAR
TWIN CIRCULAR
DUMB WELL
DOUBLE-D
TWIN-HEXAGONAL
TWIN-OCTAGONAL
RECTANGULAR
AN OPEN CAISSON
PNEUMATIC CAISSON
Pneumatic caisson are closed at top and open (during construction ) at bottom.
Advantages of pneumatic caisson
Imparts better control over work,as it is done in dry condition.
Verticality is easier to check.
Reliable quality work is obtained.
Disadvantages of pneumatic caisson
Cost of construction is higher
High degree of skill is required in sinking.
Proper health conditions are necessary for labourers
Depth of penetration below water level is limited to 35 m.
CONCLUSION
Caissons are such structures that provide a good condition to work. And hence the use of caisson gives a better quality of work.
