2 ft grid topo of intersections

[land butcher]

Has anyone on here ever been required to topo a active intersection, min 4 lanes each direction, on a 2 foot grid.
If yes, how did you do it without shutting down the intersection or parts of it.

[Jim Frame]

Sounds like a job for a scanner on a Sunday morning.

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[Dave Lindell]

That's four times as stupid as the request I got to do a 4' grid.

Did a lawyer ask for that?

[Brian8612]

A 2 foot grid is crazy. For one thing it's way too much information, and you will have to close lanes to do it safely. Apparently in the individual asking for this has no concept of how a road is built or how to survey it.

[bruce hall]

I am with Frame on this one. Also a 2 foot grid is a waste of time I would think. Been asked to do 5 foot grids but we had flagmen and some lanes were already shut down for construciton.

Why the two foot grid?

[land butcher]

This was a request made to me ~20 years ago, unbeknown to me the engineer was in the next room when I made some of the above comments. LOL

I understand it is becoming a SOP with govt agencies. But to meet this request sanely engineers are shooting c/l, ep and anything else they can safety on a normal spacing (~25ft) and having CAD interpolate the rest.
I am again amazed at what professionals will agree to because to call the agency what they are is ringing the bell of death to your plans ever getting approved.
Power in the hands of incompetents.

[E_Page]

I agree with Jim, job for a scanner. If that's not a possibility for you, and you can't sub it out, use a reflectorless TS.

2' seems like overkill. This must be a request from a lawyer looking to sue someone in an accident case.

[Ian Wilson]

Is it the DELIVERABLES on a 2' grid or the actual field work?

One of our clients hit us up with a similar request. When I questioned further, it turned out that they wanted the spot elevations shown on a grid. They couldn't care less about the field procedures.

Interesting comment back: Wow! Your grid is much more accurate than our previous surveyor! We could never get them to give us the elevations on a real grid. They were all over the place.

Oy!

.

[Stan_K]

We have completed this type of request on many projects. The engineer is attempting to determine the damage caused by vehicle traffic where the wheel tracks are groved or depressed. It is commom to have .03' to .09' depressions. Look at any road surface when it is raining. You will see and feel the groves! Repairs are usually made by the time these groves get to 0.10'.

We use a good reflectorless gun for this operation. Two to four setups are required to cover a 5-lane by 5-lane intersection.

Stan

[pls7809]

It's definitely a scan job, but it is best to investigate and dig down to determine if that is really what the client needs, or only what they think they need, but in reality don't know what they need.

[land butcher]

The request(s) are being made by local agency to the private design engineer.
Back when the request was made to me scanners and reflectorless were not around.
I agree that the 2ft grid is still not going to get all the ruts, waves etc. I agree that the low angle of reflectorless and some scanner views reduce the vertical accuracy.
Actually the best time to find ruts and such is during a rain with no traffic. Water truck would work too.
My issue is that office people are making basically unsafe requirements of surveyors, esp when they don't want traffic flow impaired.

Even with a 2ft grid design plan in hand, I doubt the people doing the overlay are gonna pay much attention to it. And a good paver should fill in low spots that are not potholes.

[land butcher]

Again I agree, this was in downtown LA in the middle of the week and no TC was offered. In fact, it was insinuated a three man crew was sufficient for safety. Gotta love those govt trans jobs.

[land butcher]

Interesting Lee, We had to be inventive years ago didn't we.