Driven pile under water

[pnmkapoor]

Hi,

I am doing estimate for a marine project where we have lot of driven piles (precast concrete) to do. These piles would have about 10m free length (7m in standing water and 3m above water). My question is should I consider in my estimate the requirement of cofferdam also all around the areas occupied by pile group? or These piles may be driven without isolating the area from water? If yes, how the pile setting out at the river bed would be done. Appreciate your response on this.

Thanks.

 

[rchanke]

Pile driving can be done off a barge and in most all cases will be less expensive then constructing a cofferdam, if there are no access restrictions such as limited water depths, extreme currents or tidal fluctuations etc. A flat bottom barge or scow will draft between 1.5 to 2 meters of water so your 7 meter water depth should be more then adequate.

There is a live webcam on the website below where they are currently driving 2 meter diameter steel piling both onshore conventionally and offshore from barges.

http://www.vccep.bc.ca/

 

[vulcanhammer]

You should strongly consider using a template, especially useful if the pile layout is consistent. Templates are discussed in the Complete Book of Pile Driving at

http://www.vulcanhammer.net/download/driven-piles.php

 

[Zambo]

Contact a marine piling company to help with your estimate. The piles will most likely be done from a barge and by use of a total station you will achieve the required accuracy.

It's interesting that first you mention a marine project then you go on to describe a river bed. It may be that filling is possible to get a crane to reach the furthest pile. You can then drive the piles and re-excavate the fill. A lot depends on the depth and flow of water and the cost of the equipment.

I think a cofferdam is the most unlikely method - but without full knowledge of the project I could easily be wrong.