I know most of you are doing stakeout with a GPS/Robot Combination. I am curious how this affects tedious layout which must be very accurate, building column lines and bridges.
Are you staking the column lines radially? What tolerances do you work within. Generally speaking, we are using conventional methods and stacking in the distances and angles and turning as many 90 degree angles as possible when staking both bridges and column lines.
Would love to know how technology is changing how you guys are doing your jobs.
I did a lot of small commercial stuff with a robot solo, almost all radial. It's hard work. A good robot will turn any angle just as good as a 90. I tried to use a mini prism as short as possible to eliminate rod error. I did some site stakeout with GPS but only if the elevation didn't need to be real tight, a robot is much better. I wouldn't use GPS on a building or a bridge but I don't have one of the new ones to compare.
Main instance of this for me is in house setout for builders.
I use a total station and Field Genius.
But I don't entirely rely on (trust) FG to give me the accuracy I'm after.
I use a small reflective target 20mm square, stuck onto a small piece of metal.
Its actually a 30mm piece of. 2mm angle aluminium and with that I can always tell when the target is 90å¡ to line of site.
Also set Nikon to display 4 decimals. That allows me to see what is happening. Not suggesting its getting 4 decimals or 0.1mm, but I can see what it's rounding from.
FG only fires up Nikon to take a single shot. When I get close, as in on the mark, I then manually get Nikon to read 4 shots and display mean, watching the readings as they show.
Having setout all from radiations, I generally but not always setup on a staked point and check others independantly.
I think knowing your instruments capabilities or more important, its repeatability and consistency is fundamental in any approach to this.
This is one of the best tools I have for setout
Plus the S6 or S8 of course
This is one of the very best tools I have for setout
Plus the S6 or S8 of course
Generally I'm doing four offset corners for an earthquake house rebuild - resect from three GPS points and then layout radially.
I meant to say with my little target it sits upright on a flat object (slab, stake etc) and there are no plumbing errors.
It is also very quick to move and remeasure.
That's a neat setup above. A lot like theSI 4050 Harrier.
What brand is it?
If you're laying out column lines I've been taught that it's never done radially. Set two points (longest line possible) and then set up on said points and turn 0's or 90's or whatever is needed... Not that I've done a ton of it, or that I'll do it again in the future but that's what was pounded into my head when I was part of that particular industry. Now-a-days my layout doesn't get past a few property corners and maybe a single family house (where I set the long side, set up on my two new points and spin 90's). I am a one man show, and operate only part time (maybe 1-2 jobs per month) and I run without a robot. It's a lot of walking with a bi-pod. But again, I don't rely on that as my bread and butter, it's more a hobby at this point, and the additional walking helps to shave off some area around the mid-section.
No
Lugeyser, post: 330096, member: 1249 wrote: I know most of you are doing stakeout with a GPS/Robot Combination. I am curious how this affects tedious layout which must be very accurate, building column lines and bridges.
Are you staking the column lines radially? What tolerances do you work within. Generally speaking, we are using conventional methods and stacking in the distances and angles and turning as many 90 degree angles as possible when staking both bridges and column lines.
Would love to know how technology is changing how you guys are doing your jobs.
Im not solo, but we build a lot of bridges. Everything is staked radially, from a minimum 3 point resection.
On a side note, a couple of years ago we were building a light rail line that had to tie into an existing platform that a different contractor had built on a different datum. Because of the tight tolerances, it was imperative that we be parallel so I told my guys to pull a couple of offsets off of the existing edge and to set up on one and backsight the other and then run in points in-between on line. They had no idea what I was talking about, so I went out to show them. They had no idea that you could do that.
Roadhand, post: 330149, member: 61 wrote: No
Im not solo, but we build a lot of bridges. Everything is staked radially, from a minimum 3 point resection.
On a side note, a couple of years ago we were building a light rail line that had to tie into an existing platform that a different contractor had built on a different datum. Because of the tight tolerances, it was imperative that we be parallel so I told my guys to pull a couple of offsets off of the existing edge and to set up on one and backsight the other and then run in points in-between on line. They had no idea what I was talking about, so I went out to show them. They had no idea that you could do that.
We had a large addition being shoved into two different buildings, it was all based off a site topo done by a different surveyor (no problems with his work, very good) but the buildings weren't square or straight. I had the boys pull some offsets to establish a nice long line so we could "tweak" the new building to fit better and everyone looked at me like I was an alien. You know, just use the design coordinates and move on. :whistle:
rough grade, slope stakes, footer digs, ect.: GPS
buildings, curb and gutter, blue tops, ect. ; TS/levels
MightyMoe, post: 330193, member: 700 wrote: We had a large addition being shoved into two different buildings, it was all based off a site topo done by a different surveyor (no problems with his work, very good) but the buildings weren't square or straight. I had the boys pull some offsets to establish a nice long line so we could "tweak" the new building to fit better and everyone looked at me like I was an alien. You know, just use the design coordinates and move on. :whistle:
rough grade, slope stakes, footer digs, ect.: GPS
buildings, curb and gutter, blue tops, ect. ; TS/levels
No love for the problem solver/avoider.
Richard, post: 330118, member: 833 wrote: Main instance of this for me is in house setout for builders.
I use a total station and Field Genius.
Me too, GPS is too damn slow and vertically inaccurate for my layout endeavors. (House layout)
Everything we do is done radially with stakeout sheets for each individual job prepared beforehand and the DC as a backup. Have always used two man crews with TS and a DC.
Richard, post: 330118, member: 833 wrote: I think knowing your instruments capabilities or more important, its repeatability and consistency is fundamental in any approach to this.
Amen to that brother.
Have a great week! B-)
For bridges, I occupy the lay out lines and measure direct distances and angles whenever possible (using tripods).
I then locate the RP's from the project control for a check (using tripods). Makes me feel warm and fuzzy when I have checked it two different ways and they both agree. Also measuring the actual distance between abutments and turning the actual abutment skew angle also gives me great confidence.
My old boss told me to ALWAYS pull a steel chain across abutments, if at all possible, as a final check.
I think it all comes down to doing whatever it takes so you can let that nagging feeling go and be able to sleep at night knowing it's right.
I'm not against radially staking things from control, I just like having a second method as a check.
I am not solo but a 2 man team and we do a lot of stake out for buildings.
We do stake out radially and never use GPS for such stakeout. Turning 90 is a dream but in reality there will always be things blocking your Line of Sight such as steel rebars, walls, debris etc etc.
We would use the seco sliding prism but would set as low as we could possibly see.
Radial is a fact of life, purely from an economical point of view. However 30 years ago the gear wasn't as good, and we had to make time for full grid lines, the strongest angle is a cardinal. At the end of the day, the trick is in the checking. I always take some diagonals, and as many checks with a tape to be able to sleep well. Been known to upset the odd engineer too, by sitting down in the middle of a group of workers and machines with a mini prism. No matter how much they complain, they complain more if you are out 10 mm and they happen to check it with a tape.
Generally, I do staking for single family homes. I set the four offsets to the foundation radially, then set up on an offset and check to see if the others are a 90å¡.
For columns lines, it depends, I still prefer a 2-man crew with a good I-man, its just easier. But f its a small building I might set radially, otherwise I like to set a baseline and turn 90's.
