Surveying a New Road: Is 6 Miles Enough Info to Set Slope Points?

[tribdog]

Om surveying a new road being built. The plans call for the ground to slope down at 6:1 from the edge of pavement for 6', then 4:1 to a designed elevation. The dirt guys want me to give them a point at that hinge every 100'. And on a lathe write 6'offset cut or fill to sub-grade (14" below top of pavement) and on the other side of the lathe a cut or fill to the designed elevation at 4:1.
this sounds great to me I've got 6 miles of road to stake out and I can whip this out quick. The more I think about it though the more I wonder if the dirt guys realize what they have to do. Not that I don't have faith in them, but I'm not giving them much information for what they're doing. Here's the way I see it:
since I'm putting a point every 100' we don't have to worry about one dimension but there is still one horizontal and one vertical. I am giving them point A(h,v) n=cut or fill to subgrade and m=cut or fill to designed toe. They need to find B(edge of road,subgrade), C(edge of road, top of pavement),D(hinge point,finished elevation) and E(toe,at a given elevation)
Most of these points are easy to figure out and I don't think they will have a problem, but E(h) is a tough one.
Eh=Ah-4((Av+n+2")-(Av+m))
I know it isn't hard on paper but that's a lot of math that I'm sure the guy on the blade doesn't want to think about and if he tries to just use the slope angle and until he hits the target elevation he's going to wipe out my set point.
I've only been surveying for about 6 or 7 months and I do tend to be more precise than I need to be, better safe than sorry. Does what I'm giving them seem like it's enough for them to do the job without TOO much trouble? How would you stake out something like this?

 

[michaeldouglassewell]

tribdog,
I suspect that you are about to find out why the "guy on the blade" is operating excavating equipment, and not operating surveying equipment. Don't expect too much out of these guys. Math flows out of the office, and into the ditch, not vice-versa. Cover your own rear end.
-Mike

 

[tribdog]

lol, but surely you have to be smart to run such a big piece of equipment, right?

 

[michaeldouglassewell]

Yeah, right. Let me know how you made out.
-Mike

 

[michaeldouglassewell]

tribdog,
Since a contractor is self-employed and not your employee, you may specify what you expect as an end-result, but not the method to be used to complete the work. That is, unless the method to be used is in the construction documents.
As the years pass, you will find that, more and more, you will specify the method to be used.
I really do try to be kind and polite to my contractors, and I have a tendency to give them the benefit of the doubt. Unfortunately, this has cost me thousands of dollars, and thousands of hours over the years. Not to mention the embarrassment of trying to explain how the job got screwed up by a sub-contractor, when I WAS SUPPOSED TO BE IN CHARGE.
A sub-contractor, doing a job for a few hundred dollars, can create a mess for you that takes thousands of dollars, and many days, to straighten out.
I hope this helps.
Best wishes,
Mike

 

[tribdog]

I'm not worried. I'm recording everything I put in the ground and I'm giving them what they asked for. I thought about it some more and if they "ant hill" my points they will be able to do the work without needing to do the math. If they run into problems and need me to restake it fine by me. At $175/hr I'll restake all day long.

 

[tribdog]

Also I'm not the boss, I do what I'm told, for the most part. I was mostly wondering if this was the normal way to lay this type of work out. Is this "slope staking"? When I saw what had to be done, my first instinct was to give them something that told them where the toe was and wouldn't be knocked out immediately, but like the saying goes, KISS it.(keep it simple, stupid!)

 

[michaeldouglassewell]

if they "ant hill" my points they will be able to do the work without needing to do the math...

Excellent idea.