Building Grid lines – venting some steam…
Call from project superintendent as I’m driving… “Hey, the dimensions between grid lines B.9 and B.4 is 33ft and then B.4 to A.8 is 32ft 11 inches for total 65-11. I taped between your 3′ offsets and I’m getting 60 ft. I think you busted an inch”
I had set 3ft offsets to B.9 and A.8 on the slab this past Saturday… I’m thinking that’s weird, I make mistakes but it’d be strange to be exactly an inch off.
Me to super: “I’ll call you in about an hour when I get back to the office. I stored the points as I set them – I’ll check it out.”
Two more minutes of driving, I pull over, grab the T7 controller and turn it on… compute inverse between computed grid intersection points… Azimuth 0.000, 66.000 feet. Minus 3 feet times 2 is 60 feet. For calcs, that’s a CHECK…
Compute inverse between set points… Azimuth is a couple of seconds off 0.000, distance, east side of building, 59.997. Distance west side of building, 60.006.
Cool.
I pull out my cell phone where I store my layout plots in PDF format for easy access… B.9 to B.4, 33ft; B.4 to A.8, 33 ft. Good.
But now, I’m thinking “we’d he get that 32ft 11 from??”
Pull out laptop, launch CAD, yep… what I have is 33 ft. Open PDF plans… 33 ft again – CHECK.
All this investigation takes about a half hour to check, check and check again.
Call super back… “I got 33 ft… where you getting 32-11?”
Him: It’s on the plans.
Me: nuh-huh… it’s 33.
Him: I got the plans open right in front of me, 32-11.
Me: WTF????I send him the screen shot of my 33ft and 33 ft grid dimensions…
Him: WTF??? I’ll call you back.
Turns out….
The structural designer changed the thickness of the shear wall from 9 inches to 10 inches. This is after construction, demo, excavation, etc., already started. He decided that the face of the wall should still be on grid so simply changed that one dimension.
The other subcontractors, concrete, steel (there are structural steel elements), even the plumbers and electricians were all informed. Not me though. GRRRRR!!!!!
The 3ft offsets to B.9 remain 3ft offsets.
But my nearly perfect 3ft offsets to A.8 are now 2′-11″ offsets.
Super will re-label tomorrow.
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