Pouring the 2nd floor slab on a SFR

[jar546]

There is a lot more steel work to go before they could pour the second floor and beams on the single-family residence. I thought you would like the photos.

 

[bill1952]

Starter home, huh?

 

[Sifu]

Impressive.

 

[Mr. Inspector]

Is all of that required in your area or is it over kill?

 

[jar546]

Is all of that required in your area or is it over kill?

We are in a 170mph wind zone, exposure D on a barrier island in VE & AE flood zones subject to storm surge. I don't know if its overkill but for the size of the houses and complexity, it seems appropriate. There is nothing structurally prescriptive about a home like this.

 

[e hilton]

First picture … looks like a fall hazard, the guardrail in the foreground has exposed a hole in the plywood deck someone could fall through.

 

[jar546]

First picture … looks like a fall hazard, the guardrail in the foreground has exposed a hole in the plywood deck someone could fall through.

Single family home. Lucky to have any protection at all.

 

[brokenkeys]

Gotta love exposure D. Combine with risk category 4 and it ends up looking like there's more steel than concrete.

If it were mine, I would have pushed for corrosion resistant rebar, given the location and price point.... but then again, given the price of corrosion resistant bars, I would probably lose that debate.

 

[e hilton]

If it were mine, I would have pushed for corrosion resistant rebar, given the location and price point....

The homeowner is probably 80 yrs old and figures any rebar corrosion issues will not happen in his lifetime.

 

[Mark K]

Regarding the rust on the rebar. I see nothing to worry about. If there was a reduction in cross section of the steel yes, there would be a concern and the rebar would likely have to be replaced before pouring concrete. ACI is clear that tight surface rust is not a concern. It would be appropriate to wire brush off loose rust.

Rusting of the rebar is inhibited by the PH of the concrete. Concrete cover limits access of water and oxygen to the reinforcing. In addition the building waterproofing system further limits the ability of water to get in contact with the reinforcing.

Corrosion resistant rebar is not a well defined term. But more relevant is the fact that efforts to limit rust, beyond the code provisions, are generally not warranted or used.

 

[Sifu]

Regarding the rust on the rebar. I see nothing to worry about. If there was a reduction in cross section of the steel yes, there would be a concern and the rebar would likely have to be replaced before pouring concrete. ACI is clear that tight surface rust is not a concern. It would be appropriate to wire brush off loose rust.

Rusting of the rebar is inhibited by the PH of the concrete. Concrete cover limits access of water and oxygen to the reinforcing. In addition the building waterproofing system further limits the ability of water to get in contact with the reinforcing.

Corrosion resistant rebar is not a well defined term. But more relevant is the fact that efforts to limit rust, beyond the code provisions, are generally not warranted or used.

If not mistaken, most corrosion resistant rebar can't be field modified either. Or do I have that wrong?

 

[Msradell]

If not mistaken, most corrosion resistant rebar can't be field modified either. Or do I have that wrong?

That is completely true for fiberglass rebar and somewhat true for epoxy coated rebar which according to most resources can have a coating reapplied in the field if it cracks off. However, that being said, ACI code in most cases will not allow any field bending of rebar that is larger than #4 or #5, I forget which office happened my head. Some of this is much larger than that anyway.

 

[Mark K]

Where does it say you cannot field bend larger bars? The issue is the bend diameter. Admittedly most field tools are not capable of bending larger sizes.

 

[jar546]

A lot of the steel is delivered already bent for the specific application. The bigger stuff that is.

 

[classicT]

Where does it say you cannot field bend larger bars? The issue is the bend diameter. Admittedly most field tools are not capable of bending larger sizes.

ACI 318 doesn't say that... I agree, it is not prohibited. I will agree with you that field tools most likely do not get the correct radius; however, that is because they typically use the tail or a section of pipe to get the bend, and not the proper tool with a template for the bend.

ACI 318 - 26.6.3 Bending
26.6.3.1
Compliance requirements:

(a) Reinforcement shall be bent cold prior to placement, unless otherwise permitted by the licensed design professional.​

​

(b) Field bending of reinforcement partially embedded in concrete shall not be permitted, except as shown in the construction documents or permitted by the licensed design professional.​

​

(c) Offset bars shall be bent before placement in the forms.​

 

[Msradell]

Where does it say you cannot field bend larger bars? The issue is the bend diameter. Admittedly most field tools are not capable of bending larger sizes.

As others have said I don't believe the ACI code says that Bars cannot be bent in the field however a large majority of the specifications for projects are written with a notation in the notes stating that bending of rebar in the field is prohibited. Sometimes I allow it for smaller sizes (<#6 and however).

 

[Mark K]

So if the constructions say that something cannot be done but the building department says that it can, the building department is effectively acting as the engineer of record.

 

[jar546]

So if the constructions say that something cannot be done but the building department says that it can, the building department is effectively acting as the engineer of record.

I don't believe that is correct, at least not in any State that I worked in. There may be some Building Departments that feel that way but that is not written into the law.

 

[classicT]

So if the constructions say that something cannot be done but the building department says that it can, the building department is effectively acting as the engineer of record.

Mark, I think you are taking this to the extreme due to your prejudice against code officials. You are reading way to far into what was said. I think what some are trying to say is....

If a BO is asked if field bent bars are permitted, the BO should say "Yes, where compliant with ACI 318 Sec. 26.6.3.1 and not prohibited by the EoR."​

Code officials, when asked a generic question, must answer to the code. If asking a project specific question, they should answer with the code requirement and the project specification.

That said, a contractor should look at the plans and know the code themselves so that they don't need to ask these questions.

 

[e hilton]

That said, a contractor should look at the plans and know the code themselves so that they don't need to ask these questions.

That’s a big can of worms. The contractor needs to know how to read and follow cd’s, and means & methods. The AoR needs to follow code when creating the cd’s.

 

[ICE]

So if the constructions say that something cannot be done but the building department says that it can, the building department is effectively acting as the engineer of record.

If the plans state that rebar shall not be field bent, such a statement will be in the notes. It might be in the general notes or the concrete notes. Now I can't speak for the rest of the crowd but it's rare that I would take the time to read all of the notes.

If asked I would wonder if Olaf has the strength to get past #5 bar. If a mechanical bender was used in the field...what's the difference from doing that at a facility. I can envision an issue with bending epoxy coated rebar in that the epoxy might deform.

 

[e hilton]

. If a mechanical bender was used in the field...what's the difference from doing that at a facility.

Done in the factory, they would take the time to patch any damaged epoxy coating. And in the field, they could he tempted to heat the rebar red hot with an acetylene torch to make it bend easier.

 

[ICE]

Done in the factory, they would take the time to patch any damaged epoxy coating. And in the field, they could he tempted to heat the rebar red hot with an acetylene torch to make it bend easier.

I considered the use of a torch and thought it too remote of a possibility….beyond that, there would be signs.

 

[Msradell]

Done in the factory, they would take the time to patch any damaged epoxy coating. And in the field, they could he tempted to heat the rebar red hot with an acetylene torch to make it bend easier.

Heating epoxy coated rebar or any other type of rebar for that matter is strictly prohibited by ACI codes! Heating it can adversely affect the strength of the steel in many cases. A big advantage of shop bending versus field bending is that the bends are performed in a slow continuous motion using hydraulics instead of rapid sharp jerks is usually what you see with a manual Bend.