Design Build - Sheet Piles

[CWEngineer]

I am trying to find out more information about the design build process, in particular for sheet piles. Currently our intent for a project is to have sheet piles design build.

I assume I need to provide information such as: groundwater elevation if appropriate, basic geotechnical information (soil unit weight, cohesion and friction angle) and cross sections.

Where is this information typically placed and in what format? Would I include this information in the drawings or is typically a contract writen for design build? Would I be involved with the speficiations or is this something I would leave up for the firm to take care of.

Appreicate you feedback and guidance.

THANKS

 

[spats]

You basically need to provide a performance spec the piling, which would include all the design parameters. This could either be in the normal spec book, or could be just in the form of notes on the drawings.

 

[ron9876]

I assume that you would like to have a speciality engineer design a sheet pile wall as part of the contractors resposibility. We would spell out clearly that it is the contractors responsibility to include in their contract, require a licensed engineer from your state design the wall and submit sealed drawings and calculations and show on the drawings where you want the wall and what are the general conditions for it's use. We refer them to the geotecth report for parameters.

 

[Dinosaur]

We just have it in our specs the sheeting and shoring of excavations is incidental to the cost for the excavation. The details are all means-and-methods.

If the sheeting is for a permanent wall, we would show the excavation line, the top of wall profile and the horizontal alignment and note the contractor should refer to the boring logs for available information on the soil conditions. If there are known utilities, we show them also. We also indicate they shall design in accordance with AASHTO and submit their design for review before ordering materials. The wall is bid per SF of exposed area, and is handled as a design-build item.

 

[DRC1]

If the shoring is to be permenant, it should be designed by the engineer. If not the scope of work andrequired loadings should be very specific. The required code, such as AASGTO should be specified. If the shheting is tempoary, it is the responsibilty of the contractor.It is a good idea to require to have the design done by a P.E. Temporay sheeting work is not governed by any particular code, so no code should be specified.
The biggest problem with sheeting is no one ever pays attention to the geotechnical program for the sheeting. Borings should be taken along the line of sheeting. if it is to be tied back, borings should also be done in the bonded zone of the anchorage. If cohesive soils are present, tubes should be pushed for samples. If the sheets will extend below the water table, accurate measurements should be made of the groundwater. Sometimes this means waiting 24 hours for levels to stabilize. Bori9ngs sahould extend at least 10 feet below the anticipated tip of the sheeting. Stanard laboratory tests should be run on some samples back at the lab. If the excavation is below the water table, grain size for cohesionless soils will be important. Unit weight and strength testing will be important for cohesive soils. This will probably cost $10,000 or so, which may seem like a lot, but a changed condition claim can easily be 10 times that amount.