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“Inverts shall be recorded to the nearest hundredth of a foot”
holy-cow replied 1 year, 6 months ago 18 Members · 34 Replies
- Posted by: @brad-ott
@bstrand photos, diagrams, procedure explanations please?
I don??t know what is a 12l?
Oh, it’s just one of the newer receivers that can take shots with a leaned rod, so with a long enough rod you can topo the actual inverts no problemo.
Also, if you can get the tip on the top of the pipe you can shoot that too and get an accurate diameter instead of trying to eyeball it from up top.
- Posted by: @not-my-real-name
It always amazes me how they calculate the slope of a pipe run between manholes with only two pieces of data, disregarding the 200 to 300 feet in between. Theoretically that may be fine for a design.
The only way to “as-built” a pipe run is to make measurements as it is built. Making observations at the top of the pipe, and subtracting the thickness and diameter will give you the invert, alignment, and actual proof of how the pipe was constructed.
That’s what I did on a sewerline project I did about 2 years ago. Had to meet 1/2% for about 200′ so I was out there shooting TOP almost every stick.
dd - Posted by: @jph
With the rod tilted, and sometimes guessing what you’re resting on, broken pipe, covered with crap, etc, it’s tough to pretend to get that kind of accuracy.
I’ve seen guys spending time, trying to compensate for tilt, and record numbers that show flow running opposite from reality, and you can clearly see that one pipe is lower than the other, but their notes say otherwise. Oh, well
Most manholes (I think) are designed with a “drop” or inlet invert some 1 to 2 tenths higher (or more, I’ve seen consistent 0.5′ drops in network designs) than the outlet. So for the tight stuff you have to shoot both inlet and outlet inverts. I’ve done the “compensate for tilt” method a few times using a smart level (which can read in degrees so it makes that calc even easier for us). I’ll record to a .01 but wouldn’t guarantee that – like @frozennorth and @jim-frame allude. I’d put money on a consistent .03-.05′ accuracy, though
dd - Posted by: @gary_g
While I agree on any inverts on an as-built being actually accurate to 0.01′ You can use a hidden point routine in SurvCE or record the data and use a spreadsheet. I think this is much better than sloping poles and other +/- methods.
Sounds good but I’m not sure what values the ‘H…’ refer to in the formulas
dd In Excel your data is represented by Columns and Rows, H is the column the coordinates are in so H3,H4,H5 are represent the first coordinate. Sorry I did not have the rows and columns on when i printed the pdf.
There are over 100 mountains in Asia that are like 10,000 feet higher.
https://en.wikipedia.org/wiki/List_of_highest_mountains_on_Earth
There are (at least) three ways to measure height of a mountain: height above a geoid, height above base, and furthest from the center of the earth. Different mountains get on the list for different ones of these reasons.
I think Dave’s mountain is high above its base on the sea floor. Mountains near the equator gain distance from the center of the earth from the oblate shape of the earth. Everest is high above the geoid.
.Once the structure is built over the pipe, the best you maybe able to achieve is 0.05′, and that’s on a new pipe. Trying to obtain 0.01′ accuracy on a pipe that has been in the ground for 50 years, is cracked, filled with various types of sediment is a fallacy.
- Posted by: @holy-cow
There are over 100 mountains in Asia that are like 10,000 feet higher.
https://en.wikipedia.org/wiki/List_of_highest_mountains_on_Earth
I put the smiley face on there because the Pacific volcano I live on is sometimes described as a single mountain (with 3 peaks), in an archipelago or oceanic mountain range. With the highest point on this island at 13,400′ and the base 17-18K’ below MSL it makes it the tallest mountain on the planet according to your list.
dd Yup. The details are all in the terminology used.
Wait. So, if the lowest point in the US is the bottom of the Mariana Trench at around seven miles below sea level, does that mean that my mailbox is setting 1050 feet plus seven miles high?
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