Precast Channel Slabs(roofing)

[Treat Jennings E.I.T.]

Good day everyone,

This is my first post on the forum and I'd like to say whats up to all and also see if I can get some help/insight on a pretty simple thing...

I'm looking to figure out the naming/designation for a precast channel slab (roof deck).

Looking through an old job and i'm seeing a slab designated as 9-44. The overall channel height, bottom of web to top of flange, is 9'' and I'm guessing that maybe the 44 has to do with prestressing or...who knows...any ideas or documents I can refer to?

 

[mike20793]

Do you have a picture of the cross section or the plan callout?

 

[dhengr]

Treat Jennings E.I.T.:
Have you looked through any PCI stds. and handbooks books and the like? There may be something in one of those, although I’m not sure there is any industry std. for numbering these odd shaped pieces for various functions. Ask an older Arch., SE, or any of your local precasters. When and where was it built? Who were the local precasters of that day, are there any shop drawing for the job around? Gather all the dimensions on the units, not just the depth.

 

[Treat Jennings E.I.T.]

Hey guys,

I wanted to send a picture of the plan but it really wont hold up...the drawings are quite old.

Here's all the info I know:

1. The building was erected around the 1950s. The slab is 9 inch deep and 2 feet wide. Flange 3'' thick and stems 3'' at the bottom.
2. The precaster was Southern Cast Stone
3. Building is in Knoxville.
4. Southern cast stone is no longer an operating company.

Unfortunately I was given this task by an old engineer haha. We are sort of combining our efforts. I believe that the 44 means 4 1/4'' strands.

Appreciate the help guys.

 

[kipfoot]

You might find some answers if you call a precast manufacturer like Midcon Products: Link

 

[TehMightyEngineer]

44 meaning (4) 1/4" strands would match the typical PCI designations for strand patterns. It seems like a reasonable guess.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[Treat Jennings E.I.T.]

Hey guys,

I've actually contacted midcon products already. The guy I spoke with said the designation 9-44 meant nothing to him. I actually work closely with PCI but I don't want to/shouldn't start throwing my weight around to get precasters to start searching their records. I was hoping for something documented maybe.

I searched through atleast 40 publications and couldn't find a designation.

At any rate, I've been moving forward with the (4) 1/4'' assumption and I guess we will see if any other information turns up.

Thanks all

 

[Sawbux]

I ran into a lot of these with a previous employer, used in roofs over paper machines - mostly shoring them up or replacing them.
They were popular in the 40's and 50's. Ones I saw were made out of "Haydite", a concrete with light weight aggregate produced by Olympian Stone in Seattle area. Yours sounds like a similar product.
The ones I saw were reinforced with #3 bars in the webs and wire mesh in the slab. Span was about 8 - 10 ft max.
IMHO, they were good for the original dead and snow loads and not much else. And only in a benign environment. They were susceptible to damage from moisture or anything dropped on the surface above.

 

[Treat Jennings E.I.T.]

Yea...I've read about the typical spans and reinforcements. None of them really mention strand at all. These ones we have are spanning 16' and are 9'' deep so it seems like they were made a bit differently than the "typical" channel slab.