Earthwork Calculation Discrepancy
Earthwork Calculation Discrepancy
(OP)
We recently started a fairly large earthwork project and are getting volume differences (3%) with the owner. They are using AutoCAD and LDD.
My questions are:
1. What are normal volume discrepancies? And how accurate is LDD compared to Agtek and Carlson?
2. I would like to keep good relations with the client but want to support my case. Any suggestions besides hiring a 3rd party?
Many thanks,
John
My questions are:
1. What are normal volume discrepancies? And how accurate is LDD compared to Agtek and Carlson?
2. I would like to keep good relations with the client but want to support my case. Any suggestions besides hiring a 3rd party?
Many thanks,
John





RE: Earthwork Calculation Discrepancy
RE: Earthwork Calculation Discrepancy
RE: Earthwork Calculation Discrepancy
RE: Earthwork Calculation Discrepancy
I disagree, there could be discrepancies depending upon how the existing ground TIN is created. If breaklines are not created at tops and toes of slopes, at inverts of ditches or channels or tops and bottoms of walls and steep slopes, the existing ground terrain model could be different when created by two different methods by different people.
Still, 3% deviation seems quite acceptable for earthwork quantity calculations. For a large project, you shouldn't expect better accuracy than that. I have seen contracts that do not allow any change in contract pay quantities for a deviation less than 10%.
RE: Earthwork Calculation Discrepancy
We had a roadway project where the breaklines were aligned to the hinge point (top of slope) of a roadway, but not to the catch point (bottom of slope). As a result, the contours of the engineered slopes looked really strange - a dead giveaway. The project was surveyed with lidar on 3m centers. Unfortunately, every time the laser beam hit a stick or something else protruding above the ground, it created a very short pyramid of air that the processing thought was dirt. Between the two errors, we were short 8,000 cy per mile. The project was over a hundred miles long.
RE: Earthwork Calculation Discrepancy
If so, I would just split the differences half and half .
RE: Earthwork Calculation Discrepancy
RE: Earthwork Calculation Discrepancy
RE: Earthwork Calculation Discrepancy
I know there are three common methods of calcuation. I wonder which one is the most accurate?
Even 3% will make a difference of several hundered thousand dollars on this project ($4 dirt).
I'll let you know how it come in.
RE: Earthwork Calculation Discrepancy
I know there are three common methods of calcuation. I wonder which one is the most accurate?
Even 3% will make a difference of several hundered thousand dollars on this project ($4 dirt).
I'll let you know how it comes in.
RE: Earthwork Calculation Discrepancy