Grading By Hand Equation

[imnoengineer]

I had someone show me a matrix system to grade a site by hand. It involved taking the four corners of each box averaging them and then adding them all together. A positive meant you had export and a negative meant you had import. Let's assume we had 20'x20' grid boxes and the four corners are 2, 4, 6, 8. The average of those numbers is 5. Once you have that I can't remember the formula. It was something like 5(20*20). Then you do the next box and add it to the first and so on.

 

[hydroponder]

If you are talking about calculating a volume, the equation is Length x Width x Height. In this case, the length and width would be 20 and the height (depth) would be your average cut/fill. So, if you have an average cut/fill of 5 and an area of 400 (20 x 20), you would have a volume of 2000 (400 x 5). Then you would add all of them up. Make sure to keep your cuts negative and fills positive.

 

[eea]

Four Point Method (Eng Units):

Vc = L^2 x (Hc)^2 / 108 x (Hc + Hf)

Vf = L^2 x (Hf)^2 / 108 x (Hc + Hf)

Where:
Vc = Vol Cut (CY)
Vf = Vol Fill (CY)
Hc = Sum of cuts on all four corners of grid
Hf = Sum of fills on all four corners of grid
L = Length of side of grid (feet)
108 CY = factor to convert to CY

This will result in Cut & Fill for each grid.

Example:

C = 1 F = 2
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C = 2 F = 3

Hc = 3, Hf = 5