AGTEK Cut / Fill Factors

[bwburges]

Is there any consensus industry standard cut fill factors for AGTEK? I have worked for two companies using AGTEK. The first used Cut (1.00) and Fill (1.15). My current company has been using Cut (1.13) and Fill (1.38) which I feel is a bit on the heavy side. What is everyone else out there using?

 

[PELS]

The cut/fill factors will vary from region to region just because soil characteristics are not the same everywhere. There are even some soils that will actually expand (clay soils and Mehrten formations from volcanic flows, for example) while others will shrink.

What I try to do is pick the brains of grading contractors and soils engineers and get them to describe what they have experienced in the field and over time you see a pattern that works for certain type soils in certain areas. It is definitely not the same everywhere. Most soils engineers will not commit to an exact factor in their soils reports because of the variety of soil characteristics. Different strata layers have different reactions to excavation & compaction so trying to be exact with factors is a monumental task to ask from them.

The one thing that is certain is never assume the same factors will apply everywhere. Talk to people who have had to deal with shrinkage and swell in the area you are working. Also, add disclaimers to your work documents to protect you against earthwork imbalances due to "factors" beyond your control.

 

[GrumpyG]

The factor also depends on how you price the project.
Is the the unit cost for hauling excess based on 10 CY per tri-axle load? Is it more? less?
The shrink/swell factor of the material for import should factor into the pricing quantities as well. Each company uses their historical experience to fit their pricing criteria.

I have heard of a site contractor who took the SF of fill area x .17(2 inches), divided by 27 and added that yardage to his fill amount. He then added 15% to the total. This allowed for proofrolling at fill areas.

I have used 1.10 for cut, 1.25 for rock cut and 1.15 for fill. Currently, I use the neat volumes and adjust my unit pricing based on experience.

Note that in building projects, the majority of the costs are in rock removal, paving and pipe work. On large site projects, a few thousand yards difference in earthmoving is insignificant.
Of course, on primarily earthmoving projects, that is not the case. Then perhaps, the soil properties need to be researched for a competitive edge.

 

[jartgo]

Check with you state DOT for ballpark numbers as well. I know in my state's DOT design manual, there is a map of the state, broken into regions with respective cut/fill factors. Like GrumpyG said above, the accuracy you require really depends on how you're using it. But I find this information is a good start and sometimes all you need.

 

[usaedy]

I am the earthwork supervisor for a middle sized residential builder. I am invloved in the job from concept through dedication. During the design phase of the job, I always review the plans from engineers prior to preliminary approval and once again prior to final approvals. When I check the site balance during design, I use a 1.6 cut factor and 1.1 fill factor. I use this in South East PA for areas consisting of shallow red shale soil, 3-8 feet in depth. I use 1.1 cut factor and 1.1 fill factor in areas of sand such as Jersey. In Lehigh Valley, where there is clay and limestone, I use a 1.2 cut factor and a 1.1 fill factor. It seems to work well because we crush the limestone.

I have tracked all T&M earthwork for several construction projects over the last two years. For estimates in the 1,000 c.y. to 5,000 c.y. range, I am always within a truckload or two of dirt. In the 100,000 c.y. range, I get within 5% of estimates.