Average end area volumes

[Predgw]

Pretty straightforward except I notice when one end is very small or zero, the examples don't use the truncated pyramid for that section. The NCEES practice exam was this way as well.

No big deal I guess.

 

[NJmike PE]

Are you asking or telling?

 

[Predgw]

Good point, I guess I'm wondering if the small rule is ignored, or the answers are spread enough where it would not matter.

 

[desantmf]

No, you will use the average end area for both cases. Only use the truncated pyramid or any other formula, if that road is getting smaller and is close to 0 cut/fill at one end. This should never be the case though.

 

[ptatohed]

Pretty straightforward except I notice when one end is very small or zero, the examples don't use the truncated pyramid for that section. The NCEES practice exam was this way as well.

No big deal I guess.

I noticed this too while studying - some sources would and some would not. What I noticed is that you can calc the earthwork either way and still pick the correct answer. I wouldn't worry about it.

 

[civilized_naah]

If the end area at one end vanishes to an edge (so that the volume looks like a wedge), the average end area method is appropriate. If the end area at one end vanishes to a point, then the pyramid formula is appropriate.

 

[ptatohed]

Well said Dr. G.

 

[Predgw]

That makes sense, though that is not how the Lindeburg CERM is written. On the practice exam I did the problem both ways and the answer choice would not have changed.

Thanks.