I'm curious, if you were setting curb stakes with a robot, would you ignore the cut/fill it gave (control has been leveled through) and run a level loop through your hubs?
if i did stake curb and gutter, then yes (sometimes). the no part would come into play when the profile or side slope was minimal. our edm has settings that can be adjusted for quality of measurement vs speed and also has a 'measure in two faces' mode, as well.
It depends on the slope of the curb; if it set to drain at ½ percent then I might run levels through. If it’s above 3 than a couple hundredths won’t matter. Also it depends on your robot, I seem to get a lot better vertical closure than horizontal closure on most of my robot work so I have a good idea of what to expect from the gun. I used to be the guy that set curb stakes with hub and tack and then run levels over for cuts. I then went to one gun with instrument man and one robot at same time for real time checks. The results from those stakeouts led me to go to robot layout only with super expensive 360 prism. I used to tie all stakes from two control points but know I just overlap a few points from each setup and check shots to control during stakeout. I find that I have more of a chance of making a catastrophic error because of centerline, template or profile problems so I always check work with staking file the day after staking. Last week I had a heated discussion with a super because the crew was setting curb line behind me as I staked hoping to pour by the end of day or the next. I told the super I needed to check the work at the office before I could guarantee it and he couldn’t figure that out, after all the stakes were in the ground and that’s all he cared about.
Probably what Moe said about flat grades, but I've checked between both methods satisfactorily. A freshly collimated gun, keeping the shots no more than ±400 feet, and checking into previously set hubs as well as TBM's along the way made for good looking curb. YMMV.
It starts with proper procedures, checks, gun in calibration, etc.
That said, I've used robots for years. I TRUST the elevations they give. The most important thing is garbage in = garbage out.
When you run levels through curb stakes, do you turn between every stake, or do you side shoot as much as possible and turn only at the end of the setup?
What others said; short shots, good procedures, etc. I think using the robot reduces blunders that may arise using the level ie wrong reading, typing errors, math errors. With the robot, I can really streamline the reduction process to produce a cut sheet. Long story short, I'll take the possibility of a couple of hundreths difference over a large blunder anyday.
I trust the robot, solid control, plenty of grade, longest shot under ~500'. I was just looking to see if I'm insane or what. Oh yes, S6 with the 360 prism.
> ...if you were setting curb stakes with a robot, would you ... run a level loop through your hubs?
Unlikely. Properly collimated and handled the elevation yielded by the total station will equal levelled within a couple of hundreths of a foot. That's plenty good for curb stakes.
Notice I said "properly collimated and handled". Some PLS's will insist their crews use the level because it's a little more foolproof. I risk underestimating the ingenuity of fools. In some circumstances production may be better by staking out with GPS and then running levels for elevation, and this may have more to do with the skill set of the individuals involved rather than strictly technical considerations.
A 3d traverse can also carry elevations that compare very favorably with levelled, if "properly collimated and handled" - and adjusted. Still, I very often do run levels on control.
There is some potential to bust a rod with the TS. Unless you are going to turn through every hub there is potential to bust with the level, too.
You're good to go. I used a 5601 and an S8. I always stored my shot and coded it whatever the C/F was, ie, C-1.02. I had a nice custom report in TGO to show Design Station, Design Offset, Design Elevation, Horizontal and Vertical construction offsets, and Deltas of the above. I also made one with just the design information and the code. The latter was a nice sheet to give to the contractor and/or DOT.
:good: :stakeout:
> I'm curious, if you were setting curb stakes with a robot, would you ignore the cut/fill it gave (control has been leveled through) and run a level loop through your hubs?
Not typically. As others have stated, if the grades are extremely critical and slope is tight I may level through them. More often than not the robot is more than adequate when used properly.
I am in the middle of a job where we trig-leveled 15 control points on a big commercial topo with my robot (Leica 1105). Then we set interior benchmarks from that control with the level and checking in between at least 3 control points, so far we have not found more than 0.03 yet. Fingers crossed here.
But, we had the robot adjusted 2 months ago. So keep that in mind.
BTW, We RTK'd these control points and we are within tolerance both H&V with a 30 second epoch setting.
1700 shots to date and probably 1000 more with 400 trees and the best thing is that its a local job.
Randy
It's always good to have an independent check somewhere. Trig. vs. differential level loop is a great check.
I guess if your gun has given you reason not to trust it, then yes I would run levels.
That's what I do. Works fine. Keep sights short and always do a stretch from one setup. If you move up, check at least two of the ones you are extending the staking from.
At 0.5% grade, I'd be looking at the rest of the plans. Long stretches, ok. But when they tweak things in short distances, that is where bird baths form. More of a design issue IMO.
Set and grade with the gun, maybe check with a level for something really critical. Depending on methodology I would say that if it is important enough to check with a level, may as well make it a digital level and really lock it down.
If one does not trust the gun for staking do they trust it for topo?
A good point.
I should add this little bit too; the fellow knows the robot is good, and has done levels before to prove that it is, yet he would still rather take all dang day to set a few hubs and lath. I will say he is a very nice guy, but man is he frustrating and unwilling to use the tools at hand often. Some days I wish I was just doing inspection on my own :-/
I have staked everything with a robot from silt fence to column lines and big pipes and flat curb. The robot works great. Using a level is crazy for curb & gutter! I've never done a bridge, so maybe I'd change my tune, but hopefully I never have to! 🙂
Will they actually build it to the hundredth?
Tom
Sometimes it is not the accuracy you are after, but a check using a different method to catch the change in rod height that wasn't recorded, or the incorrect offset from finish grade, the bug in the new firmware, ect. I am super confident that I can stake elevations within .02' or better with single angles over limited distances, but I still do not discount the fact that there are other areas that I can screw something up. It only takes a few minutes to set a level up for some checks.
Granted many errors are caught by people working with a string line, hammer and nails. I don't rely on that because contractors always have the incentive to get paid to build it once at a profit, then again at triple profit to fix your mistake.
Long story short people do what has worked for them in the past based upon their level of care and luck.
When I'm going to the grocery store or a restaurant after some rain or melting snow,, I am constantly noticing large puddles along some curb and gutter that was obviously the result of either a poor design, surveyors blindly spraying hubs in, or carpenters blindly building forms to hubs set by a survey crew in error .
I wonder how those things happen.