Berth Protection from ship scour

[goingCoastal]

Client wants to deepen adjacent to their wharf. The wharf is pile supported by 24" square prestressed concrete piles driven to refusal. The fronting piles are five feet off center from the face of the berth. However, the depth of cut is at the upper limit of limestone... yes the same limestone where the piles were probably refused too.

I have determined a safe deepening offset with no risk associated with berthing operations (>80 pa*). I am looking for structures in particular mats which I can overlay over the offset berm which still can handle dredging activities operating above them. Any ideas, literature, calculations, and experiences will greatly be appreciated.


* Analysis has shown a 80 pa sheer stress at bed level during ship berthing.

V/r

 

[Prepakt1]

You can use Nylon articulated fabriform concrete mats, provided there is good clearance below the props. The mats also come in various polys but these are much weaker in strength and more subject to sunlight degradation. They come in thicknesses from 4 " to 20 ". The more prop wash, the thicker they will have to be prevent lifting.It is possible that the mats can be anchored to the sea bed.
I am not aware of this being done previously but there is a proposed method of anchoring. Where is the location.

Intrusion Prepakt /marineconcrete.com

 

[goingCoastal]

Thanks for your post, and yes it is possible to anchored the mats because the pile bents are spaced 20 feet apart. Do you know the typical spacing of between mat segments?

V/r

 

[Prepakt1]

Mats can be made to any size. Usually sections sizes are multiples of 2.8M or so thats based on a loom width. Section size is usually based on how much concrete the divers are able to pour each time . Normally mat design is based on site drawings . Mats are mostly custom made for the project.

Intrusion Prepakt /marineconcrete.com