My first reaction is NNNNNNNNNNNNNNNNNMNNNNNNNNOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!
My second reaction is why would a client insist on you doing your profession a certain way? When I have my car serviced I don't insist the mechanic uses a particular brand of spanner.
hpalmer, post: 432908, member: 336 wrote: Just had a Client call and ask about using GPS to locate anchor bolts and send the pattern to the steel manufacturer and they would bore the base plates to match. I told him I did not think we were there yet and would not take the liability.
Does anyone use GPS/GNSS to stake or locate anchor bolts?
ABSOLUTELY No! Steel is unforgiving, you can't stretch it or shrink it. GPS will never give you the precision needed for that type of work. Even if you achieve +/- 1 cm, that's, in most cases, still out of tolerance and that plus or minus will not be uniform but will float from column to column.
The general perception by the layman is that GPS is balls on. It's our job as professionals to employ the proper methods of measurement to assure the required accuracy. I personally hate working with laying out anchor bolts and anything steel related but will take on large scale projects where the other site improvements come with the contract.
GPS is fine to use for topo where you have a tolerance of a tenth but never for staking and sort of fine grades, pipes, curbs or locating anchor bolts.
Does anyone use GPS/GNSS to stake or locate anchor bolts?
No, no, H-E-double hockey sticks NO!
RTK is reliable and repeatable to 1cm horizontally, period. Anchor bolts require 4 times that accuracy.
A total station is the only reasonable solution.
Thanks for everyone answering. Just reinforced my original answer to Client.
Btw, I originally told Client to have the person who told him to locate bolts with GPS go ahead and do the job.
hpalmer, post: 432908, member: 336 wrote: Just had a Client call and ask about using GPS to locate anchor bolts and send the pattern to the steel manufacturer and they would bore the base plates to match. I told him I did not think we were there yet and would not take the liability.
Does anyone use GPS/GNSS to stake or locate anchor bolts?
I've never done this type of work, but just briefly thinking about it I would say hell no, might consider using the GPS to set up resection control but there would be a ton of total station and tape checks.