Setting out

[Tyke2]

I worked on a scheme of townhouses in a terrace. The engineer set out using his laser total station, all computerised and accurate to within 3mm.  I called on site and could see that the setting out "pegs" were zig zagging down the line. The pile layout was in  a straight line.

So using a tape measure , 10 mins later all were reset correctly using the foundation drawing and a tape measure.

remember if it looks wrong, it probably is wrong.

[Tyke2]

Also.... A good setting out engineer, regardless of what equipment he is using will take check measurements  - using a tape, before he is satisfied all is well and leaves site.

They should work out the diagonal distances (hypotenuse) across a sample of the squares across the  foundation to check for square. Also take a few check measurements to site boundary, road etc. They should record these checks for future reference.. This is to a) make sure its correct. B) to safeguard against someone moving the pegs(or whatever) either accidentally or purposefully and then claiming against them.

As a young engineer If I returned back to base, my boss would ask to see my record checks in my level book. If I couldn't produce them I would get sent back to site to do them It only happened once!

Edited September 16, 2018 by Tyke2

[ProDave]

I thought the "selective availability" (deliberate scrambling) of the GPS system had been turned off and we were now getting full accurate resolution. but looking at the GPS track from yesterdays sail, at least one leg which I know we sailed straight is showing as a zig zag, and peak speeds of 14 knots (on a 25 foot sail boat, I don't think so) suggests it is not as accurate as we might believe.

[jack]

We had a guy come onsite to set ours out. He was an utter bellend. Spent half the visit moaning about how architects use relative rather than absolute references and that it was a huge effort to straighten out, but not to worry, he'd sorted it.

 

After he left, I realised he'd made a complete ballsup of a couple of points. They weren't even in the ballpark of where they should have been. Everything else was perfect, but I don't know what would have happened if this hadn't been picked up.