Construction Layout – Tolerance issues
Need some advice on how to address and solve an issue.
I’m interning for a large GC and have been tasked with completing the layout for a large residential building. When I arrived, the site had control already established via 4 reflective targets and two crosscuts which I have been using to setup my SPS930 station (SPS930 with T7 controller using SiteWorks). As the site has existing buildings and varying topography, I usually establish position with 3 targets and/or crosscuts which generally gives me HA error of less than 5 seconds, and VD and HD errors of less than 3mm.
We have now poured most of the foundation along with some small sections of walls and columns, and had a survey done to check locations, which revealed that the relative error of points is <25mm however every point is shifted horizontally by 50mm. I was hoping some more experienced users know the most common reasons for shifted coordinates and how to avoid this on future projects?
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