Adjusting Utilities to Grade on Grind and Overlay Project?

[raydefan]

Typically on all grind and overlay projects (where the existing and proposed finished surface is at the same elevations), I have always specified for all manholes and valves to be adjusted to grade without giving it a second thought. This is usually at the direction of the City I am working for.

Why do these utilities need to be adjusted to grade if the grade is not changing?

I have also seen it where we specify double adjust on grind and overlay projects and single adjust on reconstruction projects. What is the difference?

 

[Drumchaser]

I would guess your double adjust is referring to the initial adjust of lowering appearances to the milled surface elevation so as not to incur costs associated with front end alignments, wheel balancing, and any other problem that a manhole ring and cover or valve assembly will cause a vehicle who's driver aims for all obstacles in it's path.

The second adjust would be the "final grade" of the overlay.

Note* just because you are putting back what you take off does not necessarily mean you will be at the same elevation.
When grinding (milling or planing) you can only cut slope or depth....not both...which can cause some folks problems.

One more tidbit....after the initial planing...unless the location (wheel path) and or projection limits anything other than lowering the utilities, temp. material placed against and tapered down the the riding surface can be utilized in place of a full blown adjustment(s)...if your time of exposure is minimal.

 

[raydefan]

Thanks for the reply Drumchaser. Regarding your last sentence. I've seen contractors protect in place large electrical vaults and telephone vaults by adding tapered AC pavement. Do they typically do this with SD and SS manholes or water valves?

Also, on full blown AC pavement section replacement (not grind and overlay) do contractors "double adjust" utilities as well? I seem to recall a project where the agency only wanted us to specify "double adjust" on grind and overlay...not remove and replacement.

 

[cvg]

I have not seen double adjust on mill and overlay projects. Single adjust is specified to make sure everything is flush at the end of the job. However, Contractor will do everything possible to match the existing finish grade so as to avoid any adjustments at all. (unless plans specify a change in profile or cross slope)

 

[Drumchaser]

raydefan

*full blown AC pavement section replacement*
I will guess this work would be done out of traffic, in which case one adustment would suffice...right? Remove and replace does not include enough info. as to phasing or staging. (where will the traffic be)

The bottom line is you have to exercise reasonable care and intent to protect the traveling public (and their vehicles)whether this is one adjust, two, or temp. ACP tapers etc. How long will traffic be exposed to the bumps in the road? How much do they project? What is the posted speed? Is there lighting in the area? Are the obstructions in the wheel paths? Can a reasonable driver proceed through your WZ unmolested?
Every case is unique.
Usually a milled surface will be exposing manholes etc. for a minimum of a few days depending on the situation.
And temp. ACP tapers will work with no adjustments necessary. You need to include language in your plans to provide for the temp. ACP placement and removal.



I would concur with cvg on single adjust for a vanilla mill and overlay. In my world we have notes included in the plans that directs the contractor to coordinate with (others) the city or municipality with regard to adjustments (when necessary), the others tend to their own utilities.

 

[raydefan]

Thanks Drumchaser. You're right in that a single adjustment would be adequate for AC pavement section reconstruction because cars wouldn't be allowed to drive on the surface until complete (unlike mill and overlay which the car can drive after milled).