Creating RFP for control benchmarks for layout.
Hey All,
We’ve been doing our own layout for sometime now, but seeing as how we are just a construction company, we’ve always worked off of established control. Before I came along, they would use the client’s contract surveyor, usually the one who did the boundary work for the site, to establish control points on site to be used for layout and machine control. Most of the time, we would get guys who would come out, set a few points with RTK, and either turn over a CSV from their collector right then, or we would get an email with point names and coordinates from the PLS. When we would check into these points with our equipment, we would see busts in the range of 0.06-0.15′ as they were probably set with rapid Topo observations using GNSS.
Ideally I’d like define where I’d like to TBM’s to be set, then to request a drawing from the licensee showing names, coordinates (both SP and GRID), and the locations of the TBM’s that they’ve set, along with some documentation for how they converted from their working coordinate system to our site’s grid. I would like for these points to be established with a total-station ran in a true closed traverse for horizontal, and have a level run from an established benchmark, either a static point or monument, through them for vertical. I know this seems like overkill, but the tighter their control, the tighter our layout. I come from a dimensional control background where I want everything to be as tight as possible.
I am trying to create some standard proposal language to be used when requesting bids or proposals for a survey crew to come on site, and establish a network of control benchmarks to be used for layout. I’m wondering if you guys might have suggestions for any specifics things I should include that you may have learned through past experiences.
Any thoughts or suggestions?
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