Older(er) Drawing Notation for Concrete Beam Ties

[bookowski]

Does anyone know what the following designation means. Building is from 1982 in NY, concrete. On plan there is a typical perimeter spandrel beam, shown in section it is noted as having #3@12 closed ties (which does not satisfy d/2) with a note that extra ties are required where "ET" is shown on plan and to refer to the extra tie schedule (schedule is on top/middle of attachment).

The extra tie schedule notes #3 as the size and for spacing uses "Spacing EE" which I am guessing means each end. I had the following guesses:
- 6/5 means 6 ties @5", however they use the @ designation everywhere else for rebar spacing so I don't know why they'd mix it up here
- @6" for the first 5ft?
- 6/5 refers to left/right ends respectively, so 6 ties and 5 ties - but how many, spacing, over what length? Is it implied one extra between each basic shown in section?

There is a beam schedule for other beams in the building and it uses similar designations, i.e. under stirrups it will say "10/6 Bal @ 12". I have a full set of drawings including typical beam details and there is no explanation or abbreviations/symbols section - good set of drawings otherwise.

Doing some modifications in this area that will affect shear. Image attached.

 

[paddingtongreen]

On Sect. 1-1, it says @12". I take this, with the note on the tie table, to mean 5 extra ties wherever "ET1" is called, in between the standard #3@12. or

11 #3 ties @6" each end, #3 ties @ 12 in between.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[bookowski]

That was one candidate for me as well but I'm not very confident. You are interpreting 6/5 to mean @6" o.c. for 5 extra ties. With that logic the basic beam schedule has the first beam ties listed as "10/6 Bal @12" which would imply 10" spacing for 6 ties, then go to 12". Maybe. Seems like it would have made more sense to word as 5 @ 6" in keeping with their use of the '@' symbol on all other callouts.

 

[dhengr]

Bookowski:
Do you have access to the inside face or bottom of that spandrel beam? What would a metal detector, stud finder or compass needle, for that matter, show when it was scanned/moved over the #3 tie spacing on that face? Can you correlate some of these indications and spacings with the crazy notation?

 

[bookowski]

I haven't had good access yet but I will at some point. I was thinking of having the cover chipped away in a few areas to try and see if I can measure spacing and make sense of the notation.

 

[paddingtongreen]

We're not looking at the same thing. On Sect 1-1/1a-1a, it says" #3 [ties] @ 12" o/c For added ties shown on plan thus, (ET1) See tie schedule."

I agree the schedule isn't clear, but it must mean 5 extra ties spread equally in the first five spaces. The tendency was to use even spacing and then split the differences because it made layout easier to eyeball. first the main spacing and then the added bars.

That drawing takes me back.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[hokie66]

Takes me back as well, but I am not sure what it means, and would have the same question as bookowski. No chance the original design engineer can be asked the question?

 

[Agent666]

There isn't a standard notes sheet at the beginning of the drawing set that explains the notation, or perhaps in the spec?