This Content Originally Published by a land surveyor to Land Surveyors United Network
Hi James, NO target is permanent, until you are sure it is not moving anymore. As your building grows, the bottom floors will load and the upper will lean and sway. The method you are using without any external off set scale face targets to check your internal targets. Now you must check your lower targets for movement. Marking where the plumb center is on any upper floors then removing it , then placing it back does not mean it has not move. You must re- target a permanent lower target ,that you know has not move to replace , that target again, then move up to the next floor or targets. So what is the distance range of your laser and the Accuracy Factor, you must stay in that, to set up what floors have a permanent target to extend upward, and these still have to be checked, because your building will move. External Face Targets offset scale checks would help you if they are possible. If your laser has any error the farther you use it ,the more you will be out so Turn it 90, then 180 to make sure it lines up. Corrections must be made, because your building is going to move. Next how far up are you going. how wide is your building Foot print. I will also give you a link to a Civil Engineering site on Control of Verticality this has a lot of good info. Every Building is different,so every one of them is a leaning Curve.
I have never used resections off of Targets, , can you explain?
I hope this Helps.
James all this google book is here ,just scroll up then back down and you will see the whole book, the pages you need.
Hi James ,you sound like you have everything in control, I did not mention the nails ' I knew it was covered in both of the links i gave you. if there is no other way, to see your Target controls, a resection will have to do, but i suggest doing it manual and solve these triangles, yourself, Resections programs use best fit, they will give you a closure, but they also places these coordinates as best fit. if every thing is very close , than that is fine. to compare all your calculations, SAS or resection 2 or3 pt's, do a distance ,distance intersection from all your controls, to compare, there is no program adjustment in it the same with SAS.. hope this helps. I prefer everything at Right Angles, If you can offset your controls to do this.
also thank you, for your thanks, and you are a very good Surveyor.