Trying to locate a point in a pipe where it deflects. There is no access and it's a 30" Steel pipe under a railroad track. Can't set up low enough to observe. Some suggest setting the instrument in the invert of the pipe. I don't see that working. Drew a rough sketch for visualization.
Any ideas. I'm kind of stumped at the moment.
Need to excavate both ends so you can set up normally to attempt to shoot through pipe the full distance, knowing you probably will not be able to see that far. Also need powerful light source run through pipe or as far as possible from each end. Triangulation. Reflectorless.
>Can't set up low enough to observe.
Mini tripods 😉
I borrowed them, no idea when to buy them.
I've set up low enough with them to scan under "overhang" on a subway platform.
> Trying to locate a point in a pipe where it deflects. There is no access and it's a 30" Steel pipe under a railroad track. Can't set up low enough to observe. Some suggest setting the instrument in the invert of the pipe. I don't see that working. Drew a rough sketch for visualization.
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> Any ideas. I'm kind of stumped at the moment.
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Should have added it is in a creek bed. Flooding may be a concern. Thanks anyway. Believe we may give it a try and see what happens.
I am assuming it is worth quite a bit to determine how to remedy the problem or you wouldn't have been called to help. Put the burden on your clients to provide you a suitable working condition.
Maybe you need to call in some mine surveyors with upside down machines and create the equivalent of a spad from which to hang the machine.
Whats in the pipe, is it flowing full of water. They make systems for running a camera on tracks up the pipe to look at the condition of it. This is normally done for sanitary sewers but could be done here. As far as I know it won't give an elevation but it might let you see what you need to.
Jim...like this one?
Just need to find a really short I-man.
In this case we needed to see underneath railings. We bought this "mini" tripod at our local dealer, Precision Laser Instruments (PLI) in Ambridge, PA. We also have a "corn field" tripod that goes the other way (tall):
That's a big pipe but, I bet someone, somewhere, makes/ rents/ sells a 30" mandrel (or similar).
I would get good control on the pipe ends and pull a mandrel with a graduated line, noting where the deflection is encountered. With distance from end of pipe and good location on your pipe ends, you have a reasonable position on the defect.
Just a thought. And, going a little further on that track, I bet your closest (larger) municipality knows a utility contractor (or sub of that contractor) that does this often enough to own that equipment (30" mandrel/ whatever).
Sounds like some fun. Stay dry and make sure to let us know how you solve the question. Should make a good 'file for future use'.
I wonder if using one of those pipe lasers that are set up when installing these type pipes would work. If the laser ran along the invert of the pipe on one end, then the other, you could possibly have enough info to solve the problem.
If you knew the invert elevation on both ends of the pipe and could determine the slope of the pipe in both directions on both ends to some degree of precision, it wouldn't be that much of a stretch to compute where the two slopes theoretically intersect. Unless it needs to be done to some super high level of precision, I'm thinking 6' carpenters level and folding stick tape to determine slope. The assumption being that it's not bent and sheared somehow. A super straight graduated 20' 2x4 and a bubble level might also work for getting the slope farther in the pipe. Or would that be too simplistic an approach.
No access as in no access to Railroad property or you can not get to the end of the pipe? How far below the tracks is the pipe?
Can you probe? Put a paint spot at 2-foot increments from one end to the other. Set up a level and get elevations at these spots. Then probe to the top of the pipe at each location and record each depth. This then gives you the profile of the top of the pipe in relationship to the ground above. Then do a slope intersect of the pipe profile to figure the bend point.
That is what I was thinking, but a 20' long straight angle iron on the top of the pipe, sticking out 10'. Shoot it near the pipe, and at the end, you can calc the slope on each end. Do an intersection.
Hire a plumber with a snake and a locator or maybe a directional boring outfit with a sensor, maybe?
Early laser alignment tools included a tinted plastic target. These were placed in the flow line of the pipe and the laser showed as bright dot on a graduated scale. Pipe laying crew set laser at the upper end of the pipe and set grade. laser dot on target would tell if they were high or low left or right and the exact amount. You should be able to rent a pipe alignment laser locally.
Your situation would require a sectional pole or cord to move the target and hand held telescope or binoculars to read the scale. Be careful not to look toward the laser! Observer should be above laser at the same end of the pipe. Attaching a cloth tape to pull the opposite direction from the cord would provide stationing through the pipe.
EDIT: Enough sections of range rod to reach through the pipe would both move the target and give a series of one foot increments of distance.
Pipeline Scanning
Have you looked into Pipeline Scanning
Get a smart level from lowes , get inv at end of pipe .measure distance to the bend with level rod , put smart level on pipe or flat 2 by 4 . use the smart level slope and distance to calc the change in height . Report it plus or minus .
How do you know it deflects? Why is it necessary to locate? Inquiring minds want to know?
😀 Thanks guys. Appreciate all of y'alls input. Plan to use a little bit of everything I read here. Let you know how it works out.
Thanks again
