Non-contact rebar splices

[bill1952]

Do you allow non-contact splices in an IRC building footing? Same 40 diameter overlap? (The fact rebar isn't even required in my seismic zone shouldn't matter.)

 

[ICE]

I did. It was rare that I encountered that.

 

[Mark K]

Allowed by the concrete code.

 

[Msradell]

It will depend on the local interpretations and code requirements but I have to ask why would you want to have non-contact slices? ACI 318 7.5.1 requires securing reinforcement prior to concrete placement and easiest way to comply with that obviously is contact splices that are wired together. What you hope to gain by having noncontact slices? Is this a do-it-yourself design or was it done by a design professional.

Allowed by the concrete code.

Under very limited conditions, what portion of the code are you looking at? What code allows vs. what's done in the field unfortunately is very different in many cases. I've seen many contractors wet stick dowels into footings but that if not allowed by code for instance.

 

[bill1952]

It is not by a registered design professional. I'd read in several studies it was actually stronger, and none to the contrary, and ultimately wondered if it was accepted. No mention of non contact splices in the IRC.

 

[ICE]

If the entire circumference, and all of the deformations, can bond to the concrete the result is stronger than if the bars are in contact with each other.

Another surprise is this: My SOB provided a CalTrans report where they tested the fc of concrete that was dropped 150' with rebar cages. The concrete was not vibrated. The fc was greater than if it was placed gently and vibrated.

 

[bill1952]

Well, I really want to use to non-contact spliced I the grouted cells of 8" (2 cell) block, which would seem to meet ICEd first requirement. Again, ignoring the IRC and/or accepted engineering practice does not require the grouting and reinforcing at all of these short stem walls.

 

[ICE]

Well, I really want to use to non-contact spliced I the grouted cells of 8" (2 cell) block, which would seem to meet ICEd first requirement. Again, ignoring the IRC and/or accepted engineering practice does not require the grouting and reinforcing at all of these short stem walls.

In grouted CMU the rebar is tied to keep it in place. It matters with retaining walls depending on the design as the rebar might be to one side or the other.

 

[Mark K]

It will depend on the local interpretations and code requirements but I have to ask why would you want to have non-contact slices? ACI 318 7.5.1 requires securing reinforcement prior to concrete placement and easiest way to comply with that obviously is contact splices that are wired together. What you hope to gain by having noncontact slices? Is this a do-it-yourself design or was it done by a design professional.

Under very limited conditions, what portion of the code are you looking at? What code allows vs. what's done in the field unfortunately is very different in many cases. I've seen many contractors wet stick dowels into footings but that if not allowed by code for instance.

So you have identified that the contractor who wet sticks the dowels is in violation of the code..

Design professionals will use both types of splices as warranted.

Reinforcement is commonly held in place by chars and dobes.

With regards what is acceptable for concrete construction we look to ACI-318. With regards to ACI 318 there is not much room for local interpretation and if they conflict with ACI 318 I suspect that they are wrong.

One of the things that contributed to the problems identified after the Northridge Earthquake with steel frames was the process of normalization of deviance. Over time inspectors started accepting deviations from the code and as time went on the accepted deviations became greater and greater. This talk about local interpretations suggests that the same process is happening this time with concrete construction.

 

[jar546]

One of the things that contributed to the problems identified after the Northridge Earthquake with steel frames was the process of normalization of deviance. Over time inspectors started accepting deviations from the code and as time went on the accepted deviations became greater and greater. This talk about local interpretations suggests that the same process is happening this time with concrete construction.

Deviations = laziness and complacency. Laziness and complacency = dereliction of duty. Dereliction of duty = public risk

Interpretations of non-prescriptive methods should be left to the design professional of record, not the inspector, plans examiner, or building official. If something is not clarified on a set of plans then an RFI is in order until it is clarified. That should be coming from the design professional of record and if they refuse to clarify, that portion of the job gets stopped.

 

[Msradell]

So you have identified that the contractor who wet sticks the dowels is in violation of the code..

Reinforcement is commonly held in place by chars and dobes.

With regards what is acceptable for concrete construction we look to ACI-318. With regards to ACI 318 there is not much room for local interpretation and if they conflict with ACI 318 I suspect that they are wrong.

One of the things that contributed to the problems identified after the Northridge Earthquake with steel frames was the process of normalization of deviance. Over time inspectors started accepting deviations from the code and as time went on the accepted deviations became greater and greater. This talk about local interpretations suggests that the same process is happening this time with concrete construction.

I certainly agree with your interpretation when sticking Dwls (actually wet sticking Bars) and the use of chairs and dobes but the interpretation of ACI-318 varies between different engineering firms. I see many projects come across my desk that call for class B splices yet the engineer provides a splice table and quite a few cases a very significantly even know they are all based on the same code?

 

[e hilton]

yet the engineer provides a splice table

probably part of the boilerplate details and specs.

 

[bill1952]

Just trying to understand why for IRC buildings - per my original post - ACI 332 is not used which, I believe, allows wet sticking dowels in footings and is allowed by IRC instead of ACI 318?

 

[Beniah Naylor]

Non-contact rebar splices are common when using ICF forms, and I believe most ICF manufacturers recommend them.

The problem comes when they use ICF for a pool and have to bond all of the reinforcement together for NEC purposes...

 

[bill1952]

Interpretations of non-prescriptive methods should be left to the design professional of record, not the inspector, plans examiner, or building official.

Do you interpret ACI 332 as non-prescriptive? For instance:
3.8.6 – The dowels should extend at least 12 in. (300 mm) above the top of the footing, and 6 in. (150 mm) into the footing. If the depth of the footing is not adequate to develop a straight bar into the footing, the bottom of the dowels can be hooked. Unless prohibited by local code, the dowels may be pushed into the fresh concrete (also referred to as wet setting of dowel) immediately following striking the final level or they may be positioned in the footing form by driving them into the subgrade before concrete placement to maintain their vertical and horizontal positions as well as alignment.

 

[my250r11]

It depends on how the AHJ interprets the footing. If considered Structural Concrete then ACI-318 would used and must be tied in place before poured. If non-structural then ACI-332 could be used IMHO.

 

[bill1952]

It depends on how the AHJ interprets the footing. If considered Structural Concrete then ACI-318 would used and must be tied in place before poured. If non-structural then ACI-332 could be used IMHO.

When is a concrete footing non-structural?

In R403 Footings, under General: "Concrete footing shall be designed and constructed in accordance with the provisions of Section R403 or in accordance with ACI 332."

I'm perplexed.

 

[ICE]

ACI-332-14
Page 32 ---7.3.4.1
A vertical No. 4 dowel shall extend at least 36db
into the wall and 6 in. into the footing at a maximum of
24 in. on-center along the footing. To facilitate positioning
before concrete placement, vertical dowels are permitted to
be driven into the grade in the bottom of the footing.

That is a contradiction with the CRC:
R403.1.3.5.3 Support and cover. Reinforcement shall be secured in the proper location in the forms with tie wire or other bar support system to prevent displacement during the concrete placement operation. Steel reinforcement in concrete cast against the earth shall have a minimum cover of 3 inches (75 mm). Minimum cover for reinforcement in concrete cast in removable forms that will be exposed to the earth or weather shall be 11/2 inches (38 mm) for No. 5 bars and smaller, and 2 inches (50 mm) for No. 6 bars and larger. For concrete cast in removable forms that will not be exposed to the earth or weather, and for concrete cast in stay-in-place forms, minimum cover shall be 3/4 inch (19 mm).

 

[e hilton]

The problem comes when they use ICF for a pool and have to bond all of the reinforcement together for NEC purposes...

Is simple tie wire acceptable for bonding the rebar, or does it require a connector?

 

[ICE]

Is simple tie wire acceptable for bonding the rebar, or does it require a connector?

Pool rebar is tied with wire.

CEC
680.26(B)(1)(a)
Structural Reinforcing Steel. Unencapsulated structural reinforcing steel shall be bonded together by steel tie wires or the equivalent.