Construction stakeout control

A couple of things come to mind that I learned early on..

It doesnt take any longer to do it right than to do it wrong.

Well begun is half done.

Spit rolls down hill, unless of course youve used a bad contrrol point.

check,check, check, then recheck.

Locate , check and reference control should always be the first charge on a job.

That being said, is he liable or not? That depends.

How bad is the control bust?

Absolutely!

Check ALL of the “control,” INCLUDING running GOOD LEVELS through all of it as well.

Law of the Seven Ps

Loyal

Lets use 0.30'. All other control checks within a couple of hundredths. Verified by closed level loops.

We are also talking slopes of 0.20%

Did he hold the bad elevation and run his own control from there, or did he get back on further up the line?

Held bad elevation for two manholes. Then used the remaining control for the remainder of the job.

I say he is responsible for some of any reinstallation of any manholes that we're installed by using the bad control.

You have to check the control for the project, period. If you don't your partially to blame for any mistakes using any bad control.

slopes of 0.20% !

The goodstuff is going to stack up and go backward to get out if there is any *crew-up!

Derek

Sounds like that $1.7 mil is going up. This is the second thread in a week where somebody got hired to stake a job with other peoples control, and it didn't fit. What are we coming to..

Too bad it isn't 3' instead of 0.3'- much easier to find. Maybe there is a manhole with a 1' change in inverts...let the engineers figure that one out. Then the bust won't matter.

Back in the old days they ALWAYS laid sewer from the outlet and went uphill from there. Then it always drained. It seems in the past 20 yrs or so they've gotten away from that. Starting in the middle of runs, and sometimes even lay pipe backwards. Always scary IMO.

All the more reason to check the control before you ever set one hub. Then pass the baton if something is unacceptable. Sometimes .3' is no biggy, but this seems to be not one of those times. Good luck

.2%? Must be a big pipe for man sized turds.

$1.7M doesnt get a real long ways on big pipe considering how deep it has to be, so it must be a relatively "short" run. What maybe a mile and a half tops? 15 manholes?

Tell him he has to pay to move the rest of the line to match his first two runs 😉

Is he a sub or work for the contractor inhouse? I doubt he can or will payup, the pee match is going to be between the contractor and the design who will probably split it 60%/40% in the contractors favor. Staker probably just ruined his reputation and that is probably a good thing. Good Riddance.

Starting at the ultimate invert and using the plan grades from there carrying the elevations along uphill was always the way to go go avoid the obvious problems. But now with all the high tech toys good sense often goes down the toilet.

As an absoute minimum, the surveyor needs to check between the control that will be used to ensure that the site control is consistent among itself.

If the locations and/or elevations of the proposed on-site improvements must work with existing on-site or off-site improvements, project control needs to be checked against offsite control and improvements to be matched.

Staking a storm system from different control points without checking among that control: definitely negligent, bearing at least a portion of the removal and replacement cost. No good excuse for this one.

What portion of the cost should be borne by the surveyor is a matter of negotiation, considering contributory negligence by the engineer and/or pre-plan surveyor, and any contributory negligence by the contractor to the extent that he had a duty to check slopes before installing pipe between bad structures. If no pipe installed, contractor is probably off the hook, leaving the split between the engineer and/or the surveyor who did the design survey, and the construction surveyor.

Too bad the contractor wasn't using a pipe laser, he may have caught the bust on his own and it wouldn't have mattered. If I was the contractor and the pipe runs we're min. Slope I sure as hell would have a pipe laser, at the very least. Or a real good topman.

> Too bad the contractor wasn't using a pipe laser, he may have caught the bust on his own and it wouldn't have mattered. If I was the contractor and the pipe runs we're min. Slope I sure as hell would have a pipe laser, at the very least. Or a real good topman.

I was thinking maybe the contractor's pipe laser was how the error was found.

> Too bad the contractor wasn't using a pipe laser...

Haven't seen a contractor without a laser in years. That's why we set stakes at 50', 100', for their checks. And then not too much more until the next manhole. At least on private jobs.

I've seen agencies require a laser. It assures alignment and the fact that there is no debris in the pipe, or a pipe didn't collapse during backfill.

Now whether their laser is in adjustment, or if they set it up properly is another question indeed.

> Absolutely!
>
> Check ALL of the “control,” INCLUDING running GOOD LEVELS through all of it as well.
>
> Law of the Seven Ps
>
> Loyal

First thing I thought of as well, Loyal. Run the level loop from the project benchmark first, before anything else.

How big is the diameter of the pipe and how long is the total length of the project?

I assume that you are talking about a 0.30 vertical bust.

0.30 can be overcome quite easily if you work it out over the total length of the project. But even if you are forced to correct it between only two manholes, if the inside diameter is wide enough, it won't have an adverse effect.

But the question was what would I do first, so the first thing I would do is bring the problem that had I found to the attention of the responsible party, and submit any proposals I have for rectifying the bust.

Yes it was a 0.30 vertical bust. Pipes in this area are 12" PVC sanitary sewer.

I found the bust when I was asked to check the inverts of the run of pipe between two manholes installed in the middle of the project. I check to three different control points as shown on the plans and also matched some existing manholes to verify the design survey accuracy. The new manholes were set to low based on the bad control so the slopes will be flatter going tom the pump station. There is about 700 feet to the pump station. They should be able to make it work.

When the construction surveyor raised his arms and declared he was not responsible for the control shown on the plans and it was not his job to verify the control in order to do his work, that the control on the plans should be correct and he was not going to verify it to do his job being he wasn't being paid to do that.

I kind of thought to myself WTF! Are you serious!

Wanting to get others opinion on this.

He may have a point. It depends on what his contract says.
While I would check the snot out of everything first, that may not matter in court.

If his contract reads (and I'm no lawyer) that he is to rely upon the control as depicted on the construction plans, technically he may not have to check them. He has fulfilled his contractual obligation by using the control points on the plan.

If the construction surveyor is not a professional as outlined by the state (not licensed) then the 'design' surveyor who stamped the drawings maybe in hot water.

Just because I would doesn't mean he is obligated to.

ALWAYS check, then "fix" the control first.

Even if it appears to work with in itself, back up and make sure it matches the ORIGINAL control it was set by. (That should be in the documentation.)

:coffee:

What's your first task to start the job?

Check between all control points for horizontal and vertical closure. If I find errors bring it to someone's attention.

Do you stake out the manholes horizontally, then use the elevations from the plan control points?

I stake out points using the horizional positions and use a level to stake out the vertical position but only after checking all points againt each other.

Do you check between the plan control points or just use the elevations of the control points for your cuts that are closest to each series of manholes, without checking between each control point?

See answer to questions 1 and 2 above.

Could a surveyor be held liable for any mistakes by not checking in between the control points on the plans only to find out there was a blown elevation on one of the control points?

Remember the courts can rule that someone is partially at fault. 25% of a $100,000 mistake plus attorney fees can take a bite out of profits. I would think there is some partial liability for not first checking. It all boils down to what a purdent surveyor would do and most would agree, our first job would be to check between control points before laying out anything.