Looking for ideas on how to compute deviations of the plumbness survey of the wall which was designed on the curve.
How tall?
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hmm... spitballing ideas...
depending on length of the wall and radius...
As-built the bottom of the wall at say 5ft intervals to establish the arc at the bottom.
stake out the collected N, E with different elevations of say + 3 ft, +6 ft , + 12 ft ect above the floor elevations and record.
You can now compare the radius length of the each arc giving you a measure of plumbness...
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As-built the bottom of the wall at say 5ft intervals to establish the arc at the bottom.
stake out the collected N, E with different elevations of say + 3 ft, +6 ft , + 12 ft ect above the floor elevations and record.
You can now compare the radius length of the each arc giving you a measure of plumbness...
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That may work well if the wall is concave as you look at it.?ÿ Probably not so well if it is convex.
There's always the low tech approach of holding a rod plumb in contact with whatever sticks out the most and measuring the horizontal distance from wall to rod at various heights.?ÿ The fact that it is curved in plan view has little to do with plumbness in the elevation view.
A perfect job for a reflectorless EDM.
Set up anywhere, shoot the bottom, or lowest point you can measure to, raise the scope and measure to high(est) point.
The horizontal distance to each should be the same.
Stake to a curve for any point on the wall, top to bottom.
hmm... i was actually picturing a large radius concave wall as I was thinking about it... if the radius is large enough still would work, but good point.
Set up anywhere, shoot the bottom, or lowest point you can measure to, raise the scope and measure to high(est) point.
The horizontal distance to each should be the same.
This would be true only if you are looking perpendicular to the wall, i.e. directly at the radius point.
That also assumes the base of the wall was actually built to design specs, and follows the correct radius.
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It seems to be an unpopular method, but scanning would be the most efficient and precise method of checking plumbness for this particular application, using processing software with built-in analysis tools.
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Set up anywhere, shoot the bottom, or lowest point you can measure to, raise the scope and measure to high(est) point.
The horizontal distance to each should be the same.
This would be true only if you are looking perpendicular to the wall, i.e. directly at the radius point.
It would be true for a set of low to high points to a vertical wall at any one azimuth. Certainly not true at different azimuths unless a special set of conditions is met.
I didn't phrase that very well.
What I should have said was that if a curved wall is not perfectly plumb and a TS is not looking perpendicular to it, a line of RL shots taken by turning the scope in the vertical plane will return values that should not be compared to each other, because the line described by those shots will run at a skew along the wall. If the intent is to check verticality at specific points, for each of those points the TS needs to be set up so that you can only see movement in one dimension - perpendicular to the wall at that point on the wall.
Now if the intent is simply to take many reflectorless shots on the wall and then build 3D faces off of the results to analyze, it is OK to set up anywhere and just take lots of observations. Which is why scanning makes a lot of sense for this project.
I did something similar late last year.?ÿ We scanned the walls with MS60's then I created a surface of the wall faces in C3D and cut cross sections at specific stations that referenced back to the design plans.?ÿ I was hired to provide the as-built data and analysis for a home builder's defense in a lawsuit claiming the walls were going to fail at some point in the future.?ÿ The way we did it felt like overkill but the estimates to replace the walls reached into the 10's of millions because the high end homes were already built and damn near sitting right on top of the walls so they were willing to spare no expense.?ÿ I've attached an excerpt of my final report showing how I presented the technical data.?ÿ I don't need any snide comments from the cheap seats about my north arrow pointing down on exhibit D.1 LOL.?ÿ That's how the wall engineer did it on his plans and we were trying to make easydirect correlations back to those plans to show everything was built in substantial conformance with the design.?ÿ It turned out to be a fun little project.?ÿ ?ÿ ?ÿ?ÿ
Nicely done, and a cool project.
Yet another reason why I love scanning total stations, and why having a couple in the fleet can really help on non-standard projects or in difficult areas.
Take a line of reflectorless shots at some appropriate spacing along the top of the wall, and along the bottom. Me being me I'd probably do a line mid way up as well. Draw a series of 3d lines from point to point at each level. Use different layers/ different colors for each level. Rotate the CAD view to a top view and examine.
A scanner would do the job real neat, with "slices" taken at various levels to examine. But you would have to have quite a lot of walls to do to make it worthwhile to acquire a scanner for just that purpose. After all - if you had 100 feet of wall and took reflectorless shots on it every foot, bottom, middle, top, you would have 300 shots. Which might take an hour to collect.
Some more information is needed to make a practical suggestion, depending on the situation the obvious answer is set up opposite the wall, shoot an array along the bottom and then stake out that array at the top to compare but depending on circumstances there can be complications.
Hate to say it, but, string don't lie; I would consider hanging a plumb bob at some distance like .3 out from the wall at the top, measure a miss to the face of wall at the top and bottom. Shoot location for the drawing and note in the departure.?ÿ
@jaro25'
@dave-lindellI tried to use vertical grid scan in survce. Set the tolerance to 0.04 but angle of incidence causes problems with steep vertical angles in the ballpark up to 0.25'. I can't setup far enough from the
face of the wall.
Set up as far away as possible, maybe more than one set up, to keep angles low. Shoot to a 360 prism, preferably robotic autotracking, held against top and base of wall - use those vertical formwork lines to get the same position.?ÿDistance from the prism center to the wall should be the same regardless of position/angle?
From the looks of it, I would mark stations on top of the wall at whatever interval is necessary. Then cut a kerf in the end of a 2x4 to hold a plumb bob string, nail a block on the bottom of the 2x4 so that when laid on top of and perpendicular to the wall the string would be a foot (or whatever distance is handy) from the wall. Have somebody at the bottom to steady the plumb bob and take a measurement from the string. Thats the cheap route. Could use some aluminum tubing instead of a 2x4 to fancy it up a little bit.?ÿ