Concrete Rebar Shop Drawings 1

[MacGruber22]

Does any body else have trouble getting detailers to provide rebar clear covers, etc. on their placement drawings? If so, does anyone have a "scary" CA note that they find useful to place on the shop dwg review pdfs? This is one of the most annoying peeves of mine. Devil's advocate: Maybe it shouldn't be?

 

[jayrod12]

I've never asked them to. It's clearly stated in the structural drawings.

 

[MacGruber22]

It *is* in the structural drawings, but I do not view the CD's as placement drawings for rebar. I just could never envision a worker locating piece marks on the rebar drawings and then flipping to the CD's to find clear cover requirements.

 

[PUEngineer]

Jay...when is the last time you've seen a rod buster with a set of structural drawings in their hand? I honestly don't think I ever have. Placing drawings should be a stand alone set of drawings for placing rebar. This thinking follows ACI and CRSI recommendations also, I believe.

Stamp them 'revise and resubmit' until the clearances are shown..?

 

[jayrod12]

its funny. My experience is 50/50 whether they've got rebar shops, or structural drawings in their hands. Rarely do they have both.

 

[MacGruber22]

One thing is known for sure, and that is the CD's do not have piece marks. I don't know how they would get by without looking at only the Cd's.

 

[dhengr]

MacGruber22:
What does a “scary” California (CA) note have to do with anything? How about, “Reinforcing shop drawings which do not show clear cover to rebar will not be accepted for review and acceptance for construction.” This note as part of you general notes on concrete, on your plans, or in the specs. Maybe people don’t understand your notes because you use acronyms which no one can interpret. When the reader needs to spend more time interpreting, looking up possible meanings of acronyms, than it would have taken you to type it out, that may be a communication not communicated.

 

[cvg]

who ever said that steel reinforcement "shop" drawings were "placement" drawings? they are done by the fabricator for use in fabricating the steel in the shop, not for forming or placing it. In order to get the bar lengths correct, the required cover does need to be considered, but not necessarily shown on the shops. the contractor had better have the CD's on the job site...

 

[dcarr82775]

Most Rebar shops I see have a nice big fat note that says they are not stand alone drawings, or placement drawings. They are to be used in conjunction with the structural drawings.

 

[MacGruber22]

dhenger - acronyms are not the issue here. And, no need to extrapolate my use of "CA" in the thread to my drawings - I do not use abbreviations on my drawings unless they are defined on the drawings. My specs specifically require rebar shop drawings to indicate bar cover, among all else. No matter how many notes or spec lines call my requirement out, I always get resistance - sometimes I get tired of prolonging the shop dwg process and accept them anyways, with the hope they will use the CD's in conjunction.

cvg: I do in my specifications.

who ever said that steel reinforcement "shop" drawings were "placement" drawings? they are done by the fabricator for use in fabricating the steel in the shop, not for forming or placing it.

Are you telling me that piece marks are not used in the field for placing bend bar? What *are* the placement drawings, then? Some combination of the detailer's and Cd's?

These are the bundles of bars they are going to get in the field with tags on them indicating the piece marks, right? What drawings do they absolutely need to place these bars...the detailing drawings with the piece marks on them, hence placement drawings. If the bundles didn't have the piece marks they would be wasting time measuring the pieces and correlating them with the CD's. I just don't see how else this could be properly performed.

 

[MacGruber22]

oop. it was meant to be "cover my a$$" notes. Typing too fast!

 

[manstrom]

I will add a note regarding cover to the shops. Before the first slab pour, I make sure that I am out there. Before they start laying the rebar, I tell them that I need to see 3 things:


* The bar orientation must match the plan (inner / outer layer)
* The rebar cover is correct 3/4" on top, more is not better
* I want to talk to the rebar inspector to make sure that he has both a set of structural drawings and approved shop drawings. I tell him / her to check both and call me with questions.

More often than not, the top rebar cover on elevated slabs is way too low.

 

[MacGruber22]

Thanks, manstrom. That last remark is always concerning in two-way structural slabs - selective demolition often reveals too much cover.

Part B of the ACI 315-99 *seems* clear to me that one of the detailer's responsibilities is bar placement drawings. I wonder how many detailers accept that as true.

 

[TXStructural]

The definition of "rebar shops" and "placing drawings" is different in different parts of the country. As an industry, we are working to improve placing drawings. I am hopeful that we will eventually manage to get full placement information, uniformly, on the placing drawings, but this will probably require better checking by the structural and contractor communities. ACI 301 will implement a few changes in the 2014 edition, and CRSI is also working to help define what is provided and used by the fabricators and placers. Obviously, the goal is to assure that the design is properly constructed.

 

[hokie66]

There are other ways of doing it. I know that most of you are talking about US practice, but in Australia, placement drawings are rarely used. The bar schedules are shown on A4 sheets, with full descriptions of where the bars go, and chairs are provided to get the right height. The structural drawings are used for control. It works, most of the time.

 

[dcarr82775]

Hokie66,

What is an A4 sheet?

 

[manstrom]

An A4 is what the rest of the planet calls an 8.5"x11" sized sheet of paper.

 

[cvg]

except that it is a different size...

A4 measures 297mm x 210mm (29.7cm x 21cm).

 

[jgailla]

That's 11.7" x 8.3". Not enough to notice, but enough to cause problems with scanning and printing.

 

[graybeach]

Showing the cover and basic dimentions of the concrete could be useful to the fabricator as a double check on the bar lengths.

At first I though CA stood for California as in maybe Caltrans is known to have good strong construction notes.