Selecting excavation equipment
Selecting excavation equipment
(OP)
The Caterpillar Performance Handbook and the Corps of Engineers use siesmic wave velocites to help determine the type / size of excavation equipment needed to excavate a given soil. Does anyone know of other methods to help determine what equipment will be necessary to excavate "hard" soil using more readily obtainable site information/data like the SPT N-value, soil density, etc?





RE: Selecting excavation equipment
RE: Selecting excavation equipment
Thanks for the information. I was not aware that the UBC had such a table.
RE: Selecting excavation equipment
RE: Selecting excavation equipment
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Selecting excavation equipment
Our worry is that the successful contractor will ultimately have a difficult time excavating and will file a "differing site conditions" claim against us. We want to insure that we have provided them enough useful data that they will be able to accurately determine the effort and equipment needed to perform the excavation. This way we can avoid any claim. We also want this data so we can determine the cost of excavation based upon the effort and equipment needed.
It still appears that the only direct correlation between "excavation effort" is through seismic velocity (Corps of Engineers and Caterpillar manual).
Thanks to those above for their input!
RE: Selecting excavation equipment
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Selecting excavation equipment
1. What would be the basis for a Differing Site Conditions claim? If the subsurface investigation fairly represents the actual conditions to be encountered, on what basis is a claim filed? Actually, I suppose you can file a claim for anything, the question is does is does it have merit and will it prevail.
2. Prequalify your bidders. Make sure the bidders have had experiance in the work you are bidding, including working in the same soil conditions.
RE: Selecting excavation equipment
RE: Selecting excavation equipment
If you are really not sure, there is no harm in contacting a reputable contractor to provide some insight into the job. Although he'll likely be bidding as well, it could help you in your estimate.
Regarding the claim, now is the time to write an appropriate clause(s) in your contract to minimize the claim. That is unless, of course, you have insufficient information for bid and the contractor has to guess. Contractor's are notoriously bad guessers.
Your original query was specific to the types of equipment that will be required. Again, as the project engineer either you or your firm should have some ideas int terms of an estimated value. The contractor will determine what equipment they will use based upon thier bid. It is not the responsibility of the engineer to specify the type or make of equipment to be used on a job.
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