Just out of curiousity...which of the following methods do you think is most appropriate for monitoring soldier beams? Please say WHY you prefer one over the other.
1) Setting up offset lines to each row of beams and then recording fallings to the face of each beam.
Or,
2) Radially measuring to a fixed point (punch mark) on each beam and comparing shots to a calc'd baseline.
I've used both methods many times and have had good results with both.
I know that the specific conditions at each jobsite need to be taken into consideration when choosing appropriate methods. I'm interested to see if other surveyors who do this kind of work generally prefer one of the methods over the other.
Thanks,
Jeff
It depends how long and how far apart the soldier piles are. But both ways work fine. It also depends on how you have the job set up, if it's gridded then a parallel baseline with offset readings at different heights keeps everybody (non surveyors included) in the loop.
Just like everything else "It depends"
Just a general comment on this type of "false work" monitoring. Leave the 1" gun at home. It's an exercise in futility, unless of course you're one of those who claims to have "topoed, paved geodetic'd and tilted" and you're trying to put on a Bullsh.t exhibition.
It also depends on what kinds of loads are on the piles themselves. I had some where I had to come up with a system to check the bulge on the wailers and put gauges on the Dywidags. This is the type of assignment where you have to think out of the box, come up with solutions and prove why you're the expert.
Ralph
Here's one I did a few years ago approx 60' deep
Laser Scanner
Get a roll of reflective tape suitable for outdoor use and cut out square pieces and place them with the point of the reflective target facing "up". That way you’ll have a good X,Y,Z axis to aim at. You can buy premade reflective targets or cheap retro prisms if you don't have reflectorless equipment.
Even if you're using a scanner, the reflective targets make it easier to find the targets in all of the millions of points you'll gather.
Agreed
On the D.L., Emm to the eye to the kay, ee, Dee has explained a great method. Strategically placed reflective tape is an awesome way to study deformation.
AS3
My son in law works at a place that makes gates for parking lots and driveways. When they get to the end of a roll of reflective tape they throw it away.
I have a friend that runs a machine shop, he pulled a piece of pipe out of his scrap pile and sharpened one end in his lathe. He also gave me a 3" plastic disk about an inch thick.
The tape is about 4" wide with orange and silver, 2" diagonal stripes. I get 6-1" disks out of each stripe plus I make as many duo-colors as I can. The tape's got a super sticky back but has a hard time sticking to utility poles and dirty sign posts. If you clean those up though, they work just fine. I use them all the time (well, when I have work) and they work great. I put the silver ones on dark surfaces and the orange on dark. I've shot them over 700' away, reflectorless.
I've been thinking there might be a market for these. I don't think it's a get rich quick scheme but it might keep me in beer money...;-)
A quick google reveals they sell for a buck 86 if you buy 250 of the smallest target. Their's are square with a redline target and a silver back ground.
You think I could get a buck 85 for mine?.....;-)
Dugger
have the piledrivers set outlookers on top of pile, square to pile line and level. 2x2 angle is good. stick the leveling type monitoring sticker strips on outlookers. set up on offset to pile line and read offsets. set up your notebook, etc. deformations are found very quickly. not the most scientific, but the pile drivers and engineers like this system.
also, keep in mind that the tiebacks are drilled in a slight decline. buck in your best level, down in the 'hole'. set good marks on each pile at that elevation. in other words, no ruler or rod, just crosshairs on the mark. set the same stickers, above, with the zero mark at elevation. concept is, if the pile is moving horizontally, it is more than likely moving vertically as well. once you set these two up, monitoring is a one person process.
practical and fast, but not the most precise. might want to intersperse with a different type of measurement, occasionally
You don't need the targets if you Laser Scan.
Believe me, it makes it a whole lot easier using reflective targets because they stand out amoungst the millions of points you'll gather using a scanner during numerous setups that will need to be taken during the monitoring process. In fact targets with a reflectorless instrument are the way to make sure you're measuring your intented targets and not some concrete splatter or dirt & grime build up that occurs on every construction site.
Consider color mapping surface differences between the first laser scan and subseuent laser scans. Compare millions of points not hundreds.
I have used the reflective tape method on bridge abutments. Apply contact cement first and let dry. Then apply reflective target. Use reflective targets for initial control on solid things such as buildings, guide rail posts, etc. Resect yourself into your datum from the control targets.
Thanks for the replies and helpful information. I don't have access to a scanner, but I'll experiment with the reflective targets in the future.
Jeff
