a good client called me the other day and asked me if i had the ability to confirm some measurements on a proposed angled glass wall. it had been asbuilt by another surveyor but he wanted a double check. after he explained it naturally it seemed easy and i said sure we can do that no problem. i went and collected the data and now my CAD techs are telling me this isnt as easy as i thought.......
see attached image..
first shot is top of angle iron
second,third,fourth shot is on the center of the steel crossmember
last shot is on the edge of the foundation.
all these items should lineup in a perfect world but the previous surveyor is showing some crossections with negative numbers which are an issue. there are about 16 of these cross sections to do and all my points have good elevations shot straight on with the reflectorless.
one of the issues we are having is that we have to draw each crossmember to get the bottom of the member distance to the proposed glass wall face like shown. ( or lower the elevations of those points by half the crossmember distance)
if we draw the line from top to bottom in microsurvey cad and switch the view to cross-section it shows it properly but we cant pick the distance because it is 3d and would be perpendicular...also not correct.....i can do it in the data collector manually but would have to cogo an intersection for all 4 points 16 times....
i assummed this was easy to do at the time but didnt think about it enough.
i am hoping there is a way i can draw in CAD exactly how this looks and pick the distances.
we have microsurveycad premium and civil 3d ( not very well trained in C3D)
i should mention dimensions in blue are moddeled/expected dimensions fromthe steel supplier/installer and red is the asbuilt dimension they supplied the project owner. they also did this with a reflectorless total station so it is possible somehow.
Thanks
Orient the points so that looking at the face is North. Export and re import using the northing as easting and elevation as northing.
I've done a few things like this in the past, plus been on both ends of that double check scenario. I suppose it depends on your tolerances. It seems the steel is there, or at least the foundations. You are the checker and not the checkee, so that's good.
For checking things with a bunch of deflections and seeming various elevations, I'd tend to go with the old reliable station/offset approach. Shoot your elevations later by whatever methods work for you.
Run a straight line as close as you could to the work, and just set temp marks opposite each key point (nail). Measure the offset with your Lufkin. Plug in the elevations on the tail end. If your CAD guys can't figure that out.... go shopping for new CAD guys.
I wouldn't do that to stake it, but you're just checking it. It really does depend on tolerances, and/or if the glass has already been cut. My guess is yes. Are they looking for your certification of "OK", or just a "looks good"
I quit doing anchor bolts years ago.... could never sleep for 4 days.
Ok Leggers, beat me up.... 😉
> one of the issues we are having is that we have to draw each crossmember to get the bottom of the member distance to the proposed glass wall face like shown. ( or lower the elevations of those points by half the crossmember distance)
>
I would think that lowering the elevation of the shots by half the crossmember distance is assuming:
1) that there is no twisting or warping of the member itself and
2) that it is installed plumb
Would it be helpful to shoot the "face" of each member at the top edge, center (as shown), and bottom edge?
Is the distance from the top edge to the bottom edge of each member significant enough to warrant the extra detail provided by 3 shots per member instead of just 1?
Great solution! This will allow you to draw your perpendicular lines. One caveat, when you re-import the points the 16 cross sections will plot on top of each other. You'll have to sort them by layer or some other method. Isn't that right thebionicman?
You could paste a fake number in excel to offset them into rows or fiddle with point groups. I just did a similar trick with 16 years of monitoring data on 4 horizontal and 2 vertical datums. I spent 3 hours thinking and 10 minutes working...