Best Method to Survey Piping
Best Method to Survey Piping
(OP)
Hi All,
Firstly let me start off by saying I'm not well versed with all the lingo associated with Surveying, so please forgive me if I use some of the terminology incorrectly. I just wanted to get some input / advice with respect to performing a pipeline survey to monitor movement of the piping over time. The area in which the piping sits experiences severe land slippage and movement, so we currently utilize a vendor to monitor the movement using established control points and monitoring points along the piping. However, recently, we've been noticing large discrepancies with the data which lead us to question whether we're going about this the right way.
We're questioning whether our contractor has been doing the surveying properly that could result in the discrepancies we've been noticing. That aside, I'd like to know what is the best method of doing this exercise to ensure the greatest accuracy of results. I've heard that GPS can be used to accurately plot the movement of the piping overtime, however, if our contractor really is the issue, then is our current method ok as is providing we can get a better contractor. Please let me know your thoughts on this, and thank you in advance.
Firstly let me start off by saying I'm not well versed with all the lingo associated with Surveying, so please forgive me if I use some of the terminology incorrectly. I just wanted to get some input / advice with respect to performing a pipeline survey to monitor movement of the piping over time. The area in which the piping sits experiences severe land slippage and movement, so we currently utilize a vendor to monitor the movement using established control points and monitoring points along the piping. However, recently, we've been noticing large discrepancies with the data which lead us to question whether we're going about this the right way.
We're questioning whether our contractor has been doing the surveying properly that could result in the discrepancies we've been noticing. That aside, I'd like to know what is the best method of doing this exercise to ensure the greatest accuracy of results. I've heard that GPS can be used to accurately plot the movement of the piping overtime, however, if our contractor really is the issue, then is our current method ok as is providing we can get a better contractor. Please let me know your thoughts on this, and thank you in advance.
RE: Best Method to Survey Piping
How are you doing this now?
RE: Best Method to Survey Piping
LIDAR is good to about 2 mm accuracy and one model can be easily integrated into another model, so it would work extremely well for monitoring pipe movement over time. The surveyor produced about 1.5B points in less than 8 hours. He was able to determine--while in the field--that one of the two chemical storage tanks the piping serves was ever so slightly out of plumb. He could also tell which part of the pipe support bents were rusted or painted by the type of reflection he saw on his tablet. In addition, he produce a ground surface topo map for us.
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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill
RE: Best Method to Survey Piping
RE: Best Method to Survey Piping
True. Years ago a water district that abutted a water district I consulted for had a problem with a buried transmission main in a similar situation to what the OP describes. I was told (probably third hand at best) that at several key locations they welded posts to the top of the pipe that extended above ground. Every so often they would survey, by the means available in the 1980s, the elevations of the top of the posts and and any rotation of the posts.
============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill
RE: Best Method to Survey Piping
RE: Best Method to Survey Piping
https://www.gislounge.com/using-gps-monitor-earths...
https://www.earthmagazine.org/article/precise-faul...
https://www.sciencedaily.com/releases/2001/03/0103...
https://www.degruyter.com/document/doi/10.2478/jog...
https://www.topcon.co.jp/en/positioning/products/p...
https://learn.sparkfun.com/tutorials/what-is-gps-r...
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Best Method to Survey Piping
Then you need a fence and solar power and landowner permission, because you promised all the pipeline stuff would be underground. Besides, its a good excuse to get out of the office once in awhile.
RE: Best Method to Survey Piping
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Best Method to Survey Piping
1503-44, you mentioned LIDAR is overkill, so I am assuming this is typically how surveys such as these are performed? Just wondering if there's anything else I can explore to ensure accuracy.
RE: Best Method to Survey Piping
You didn't say much about your pipeline, or why you are monitoring it, so its hard to say what kind of accuracy you really need. Normally lengths and levels to a few mm will easily suffice. Why are they having such a hard time with it?
RE: Best Method to Survey Piping
Much depends on how old the surveyor's equipment is; the newer, the better, assuming they spent the bucks to get the full benefit of RTK. Nevertheless, some GPS receivers are more capable than others; their designers having taken advantage of essentially "undocumented" features of the GPS constellation and the RF signals therefrom.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Best Method to Survey Piping
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Best Method to Survey Piping
I honestly can't say why they're getting so much trouble although, I suspect it's some sort of mistake they made with the data that's throwing everything off. They marked points on the top of the piping to use as measurement points but unfortunately, our painting department decided to re-paint the lines and the measurement points were lost. The contractor re-established monitoring points but upon doing so, we saw vast differences in lateral displacement which we questioned, in the vicinity of 1 - 1.5 meters! The vendor claimed that it was the painting and re-establishing of measurement points that resulted in the differences, but I can't see how that would equate to over a meter in variation. I think they made some other sort of measurement error, or otherwise.
So, I thought maybe there was a better, more efficient way to do the survey to eliminate the possibilty of errors. But, it seems to me that the technique is not the issue, rather the execution.
RE: Best Method to Survey Piping
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Best Method to Survey Piping
RE: Best Method to Survey Piping
The control points need be outside the influence of whatever geo environment the pipe points are within. Can't have control points moving on a landslide and the pipe points moving likewise too, and data showing no change from prior measurements. There is no issue using a 2-second total station, with targets that are plumb to their pipe targets. Just grab a triple measurement and average, to have a validated value. It wouldn't hurt to have a control station for the control station, as another QA check that the reference control point didn't move.
I personally wouldn't be using gps...due to lack of quality control....the measurement coordinates be slightly different through the day, and only consistent for a QA check is a reoccupy the next day at same time, to have the birds in same geometric pattern, and reading from the same birds again.