Dredging to lay intake pipe into the sea

[Andre7]

I am doing an estimate to install a water intake pipe about 3/4 mile into the sea. The sea has a slope from shore line to about 25 feet deep 3/4 mile from the shore.

The excavation needs to be about 22 feet deep at the shore line and will follow the slope of the sea floor. The geotechnical composition is about 50% sand and 50% hard sedimentary rock. We can blast.
I am doing an estimate to install a water intake pipe about 3/4 mile into the sea. The sea has a slope from shore line to about 25 feet deep 3/4 mile from the shore.

The excavation needs to be about 22 feet deep at the shore line and will follow the slope of the sea floor. The geotechnical composition is about 50% sand and 50% hard sedimentary rock. We can blast. At the end of the pipe we are working in 25 deep seas and dredging/excavating from the sea floor about 22 feet.

I am interested in unit rates for this type of work. Volume of work is significant. Dredged cross section will accommodate several pipes. Based on soil or rock I can estimate the quantities and need to make assumptions especially regarding the excavation profile - sand or rock, vertical walls versus sloped, etc.

The plan is to reuse the dredged material to cover the intake piping. Suggestions on the unit rates for dredging/excavation of rock and sand in a sea is appreciated.

 

[sbi]

Ask the Dredge manfactures lik e Thomas, Peacore or even the
rige mfg's like ? mind block, they are in ?Des Moines Iowa

SBI
Central Ne.,USA

 

[StephenA]

Unit rates for dredging can be very misleading as mobilisation / demobilisation costs for the plant can be a significant proportion of the costs.

Similarly the weather downtime / working window can be a minor or major cost, so much so that a tunnel can be cheaper in the worst case.

Ask a dredging company such as Dredging International (DEME)

Stephen Argles
Land & Marine

http://www.landandmarine.com

 

[tt340]

Hello Andre7.

Reading your thread on you Dredging project I would advise you to get in touch with a company in Scotland called Seabed Systems that will work with you on this. They are a small company but there experience on this kind of project spans thirty years plus.
For information on what they do and answers on how to approach your project drop them a email.

info@seabedsystems.com or tom@seabedsystems.com

Best regards

TT340