Wednesday, November 24, 2010

Construction of Cofferdams

 Cofferdam is a temporary structure built for the purpose of excluding or soil sufficiently to permit construction to proceed without excessive pumping, and to support the surrounding ground.
Construction of foundation is most important in a structure, so all the correct and safe actions should be taken while doing a foundation.

Cofferdam is commonly used for oil rig construction and repair, bridge and dam work, the cofferdam is usually a welded steel structure that is temporary and is typically dismantled after work is completed.
Cofferdams is used to provide a safe working space at foundation level
It’s difficult to handle deep foundations under water or ground in deep

Safety in construction of cofferdams
Construction of cofferdam presents safety problems unique to this type of construction.
They will be limited access, limited work areas, damp or wet footing, and deep excavations.
Provisions must be made for safe access in terms of adequate walkways, rails, ladders, or stairs into and out the lower levels.
The work may be within a waterway, in which case additional safety regulations may apply. These would include provisions for flotation devices, boats, warning singles, and suitable means for a rapid exit.

 
    Inside the Barge Gate Cofferdam

Inspection and Maintenance
Dams should be inspected regularly and immediately repaired if required.  A through inspection should be conducted following flood events.

Water removed from work area may be silty and should be discharged to a
vegetated area at least 30 m from the watercourse, or pumped through a filter bag

The weather forecast should be monitored to anticipate the occurrence of high flow
events.  Work operations should be adjusted to accumulate possible overtopping of
the coffer dams
       Barge Gate Cofferdam
Consideration of Selection of a cofferdam
Soil conditions
Location of the coffer dam (land/water)
Plan size of working area
Maximum depth of soil or water to be retained.
Nature of the permanent or floating structure
Effects on excising adjacent structures
Ground water level & their fluctuation
Construction time
Availability of equipment and material
Possible construction method & dismantling
Effects of noise, vibration and fumes, & fire risk.
It water cofferdam behavior of water.

Cofferdams is mainly of two types
Gravity coffer dam :-
Sheeting cofferdam 

1 comment:

  1. Cofferdams promote safety, yes. That’s the very reason why most of the construction engineers and owners of a specific building choose to use cofferdams. It is to enhance the construction progress and everyone’s safety as well.

    ReplyDelete