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#### kloodge

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I'm a programmer tasked with creating a spreadsheet to help a concrete contractor to automate the estimation process.

They currently do the calculations manually by referring to tables. I need to find the formulas for doing concrete calculations so that I can program these into the spreadsheet.

In particular I'm trying to find out the formula for calculating the cubic yardage of piers.

Is there a web resource or book that provides these formulas ?

Thank you.

#### Bob Kovacs

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You just need to enter the dimensions of the pier (in feet is easiest), calculate the volume, and divide by 27 to get cubic yards. You may want to give them the opportunity to add a waste factor to the formula as well. The formula for a rectangular pier would be =(w*l*h/27), so for a 24" x 30" x 4' pier, you'd get =(2*2.5*4/27).

For a round pier, it'd be =(r*r*3.14*h/27, so a 12" round, 5' high pier would be =(.5*.5*3.14*5/27).

Depending on how the concrete is placed, the waste factor could be in the 3-5% range- higher if it's a long, bumpy wheelbarrow ride from the truck.

Seems like the contractor should be able to give you the formulas he's currently using for this application and others, assuming he knows what he's doing.

Bob

#### kloodge

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