Ive been asked to check some piles on site, I am comfortable checking the as-built of the pin as this is just staking out the design co-ords, what would the community suggest for checking the top of the casing?
The previous way i did it, a few years ago now, was to take 3 points with a mini prism around the perimeter of the casing and then calculate the centre position.
Any thoughts on this?
Thanks
Peter
I am not familiar with locating piles but here are a couple of thoughts:
If the piles are a consistent size you could make a jig to fit on top of them to give you a consistent center point.
Or if you can write on the top surface you could take a compass (the kind with a point at one end and a pencil at the other) and extend it to just beyond the radius of the pile (assuming that they are circular). Then put the pointed end at the edge of the pile in three different places and scribe near the center, creating a small figure to place the mini prism onto
Licensed Land Surveyor
Finger Lakes Region, Upstate New York
Typically horizontal tolerances for piles are pretty loose. Find out what they are as that will have a huge impact on the method needed to locate them. Thinking they can be installed within a few hundreths is unrealistic. Likewise checking them for a few hundreths is usually a waste of effort. I would expect you will find that eyeballing center will be sufficient.
The 3 points around the perimeter works for us.
3 points also, but reflectorless.
Not quite as accurate, but quicker...
Find a bucket with sloping sides just about the same size as the piles.
Invert bucket over the pile - it will self centre.
Centre of base of bucket will give you the centre of the pile.
If you are using trimble and can see the sides of the casing....
Cogo...Compute Distance... Between Point and Line...Point Name>Measure...Method: circular object ( Options=bisect tangent) site a glancing edge on one side and Meas HA, turn to the other side Meas HA, gun will turn to center and you can hit Meas. Resulting calc shows the circumference which you can use as a check.
Line=2 points
Result is real time delta to line which you can use to direct driving operations.
For elevation you will need to take another shot, you can not use this method right at the top of the pile, need a little room to get a bite on it.
It is a good option when working over water, similar to the three rl shots but faster.
3 points on circle
Best fit circle through 3 points and draw the center point. That's how i do it in Carlson
