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All About FRP Rebar

jar546

jar546

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Composite rebar, also known as fiber-reinforced polymer (FRP) rebar, is a type of reinforcement material that is made of a combination of fibers and resin. This material has several benefits that make it attractive for use in construction projects.

One of the main benefits of composite rebar is its strength. The fibers used in the rebar are typically made of carbon or glass, which are both extremely strong materials. This means that composite rebar can be used in applications where traditional steel rebar may not be strong enough. Additionally, composite rebar is also resistant to corrosion, which is a significant drawback of traditional steel rebar.

Another benefit of composite rebar is its lightweight. Because it is made of fibers and resin, it is much lighter than traditional steel rebar. This makes it easier to transport and handle, which can save time and money on construction projects.

Composite rebar also has thermal insulation properties, it can help to reduce the temperature of concrete structures, which can be beneficial in hot climates.

However, composite rebar also has some downsides. One of the main downsides is its cost. Because it is a newer and less common material, it can be more expensive than traditional steel rebar. Additionally, composite rebar is not as widely available as traditional steel rebar, which can make it harder to find and purchase.

Another downside of composite rebar is that it is less ductile than steel, which means it is less capable of absorbing energy and more likely to crack under stress. This may make it less suitable for use in certain types of construction projects.

In conclusion, composite rebar has several benefits, such as strength, corrosion resistance, lightweight and thermal insulation properties, but it also has some downsides, such as cost, availability, and ductility. Its use should be carefully considered and weighed against the specific needs of a construction project.

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I’m a little surprised strength is number one on your list, i always thought corrosion resistance was it’s best factor. And you said it’s a newer material ... i remember being exposed to it 40-ish yrs ago when i first got into construction. That’s certainly newer than steel, but that should have been plenty of time to work out the details. I would think inflexibility would be one of the primary drawbacks, since it can’t be field bent.
 
How does the sourcing of the raw material and the carbon footprint of composite compare to steel reinforcement with respect to manufacturing.
 
jar546 said:
You should Google that. I have no idea.
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I found this:
A comparison of CFRP and conventional steel reinforcement shows the comparatively high environmental impact of CFRP reinforcement amongst all considered impact categories.
 
Another major disadvantage of FRP rebar is it you cannot make bends or even make adjustments to existing ones in the field. All bends have to be shop fabricated
 
FRP reinforcing has its place, but it is not possible to automatically substitute it for steel rebar. Strength is not the only concern. Ductility is also important.

FRP rebar is not mentioned in ACI 318 which suggests that it is not mentioned in the code.
 
ICC-ES Issues First Evaluation Reports For Fiber-Reinforced Polymer Reinforcing Bars

Reports provide confidence to safely use FRP reinforcing bars in reinforced concrete construction
Brea, CA – ICC Evaluation Service (ICC-ES), a member of the International Code Council family of solutions and the experts in building product evaluation and certification, issued the first two evaluation reports for Fiber-reinforced Polymer (FRP) reinforcing bars in accordance with the Acceptance Criteria AC454 (Acceptance Criteria for Fiber-Reinforced Polymer Bars for Internal Reinforcement of Concrete Members). The evaluation reports were issued for Tuf-N-Lite, LLC (ESR-4664) and Neuvokas Corporation (ESR-4526), providing evidence that the FRP reinforcing bars are in compliance with code requirements of the 2021 and 2018 International Building Codes (IBC) and International Residential Codes (IRC).
Acceptance Criteria AC454 applies to glass or basalt fiber-reinforced polymer reinforcing bars, in cut lengths, bent shapes and continuous closed stirrups and ties (hoops), that are used to reinforce concrete structural members. AC454 includes provisions for evaluation of FRP reinforcing bar material properties, performance under accelerated environmental exposures, performance under exposure to fire conditions, and structural design procedures. FRP bars under this criteria are used as flexural reinforcement in structural concrete members such as beams, shallow foundations and one-way or two-way slabs, and as shear reinforcement for flexural members; as well as used as longitudinal reinforcement in columns or walls.
To date, the IBC and IRC (as well as IBC referenced ACI 318) do not include provisions for use of FRP reinforcing bars as replacement of steel reinforcement. Therefore, AC454 was developed by ICC-ES to demonstrate that FRP reinforcing bars have been independently evaluated to show building code compliance in terms of quality, strength, effectiveness, fire resistance, durability and safety. Having an evaluation report from ICC-ES helps code officials, design engineers, and inspectors safely use FRP reinforcing bars in reinforced concrete construction with confidence, as well as manufacturers to safely market their product.
ICC-ES encourages manufacturers to comply with the most current codes to increase market acceptance. For more information about updating your product’s code compliance to the current codes, contact ICC-ES at 800-423-6587 or es@icc-es.org.
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I also remember something (I think Josh Porter's "Building Integrity" videos) stating the carbon/polymer rebar was less viable for tensile strength.... or am I mis-remembering?
 
It is also non-magnetic; an important trait around medical and high-end scientific equipment.

So far, the only application where I have seen it used in a structural element was adjacent to a CT machine in a CMU wall that was being infilled after install of the scanner.
 
I know of a driveway guy that uses it, sez it cost more but happy with its rsults so far. I for one have only seen it used in flatwork applications.

I would think a coastal area might see a benefit with less rusty rebar traversing through the concrete like you see in curbs.
 
Inspector Gadget said:
I also remember something (I think Josh Porter's "Building Integrity" videos) stating the carbon/polymer rebar was less viable for tensile strength.... or am I mis-remembering?
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In looking for engineer articles on internet, I read GFRP is at least 20% stronger in tension than steel, and you can therefore use less in some situations. I think it can be less expensive, but not sure if that is foot for foot, or a result of fewer pieces and lower handling costs.
 
Steel rebar absorbs a tremendous amount of energy as it stretches before it breaks, but fiberglass rebar just snaps when it is overstressed, leading to catastrophic structural failure. That is why it is not allowed for bending or seismic reinforcement. It is fine for crack control rebar.
 
Keystone said:
ICC-ES Issues First Evaluation Reports For Fiber-Reinforced Polymer Reinforcing Bars

Reports provide confidence to safely use FRP reinforcing bars in reinforced concrete construction
Brea, CA – ICC Evaluation Service (ICC-ES), a member of the International Code Council family of solutions and the experts in building product evaluation and certification, issued the first two evaluation reports for Fiber-reinforced Polymer (FRP) reinforcing bars in accordance with the Acceptance Criteria AC454 (Acceptance Criteria for Fiber-Reinforced Polymer Bars for Internal Reinforcement of Concrete Members). The evaluation reports were issued for Tuf-N-Lite, LLC (ESR-4664) and Neuvokas Corporation (ESR-4526), providing evidence that the FRP reinforcing bars are in compliance with code requirements of the 2021 and 2018 International Building Codes (IBC) and International Residential Codes (IRC).
Acceptance Criteria AC454 applies to glass or basalt fiber-reinforced polymer reinforcing bars, in cut lengths, bent shapes and continuous closed stirrups and ties (hoops), that are used to reinforce concrete structural members. AC454 includes provisions for evaluation of FRP reinforcing bar material properties, performance under accelerated environmental exposures, performance under exposure to fire conditions, and structural design procedures. FRP bars under this criteria are used as flexural reinforcement in structural concrete members such as beams, shallow foundations and one-way or two-way slabs, and as shear reinforcement for flexural members; as well as used as longitudinal reinforcement in columns or walls.
To date, the IBC and IRC (as well as IBC referenced ACI 318) do not include provisions for use of FRP reinforcing bars as replacement of steel reinforcement. Therefore, AC454 was developed by ICC-ES to demonstrate that FRP reinforcing bars have been independently evaluated to show building code compliance in terms of quality, strength, effectiveness, fire resistance, durability and safety. Having an evaluation report from ICC-ES helps code officials, design engineers, and inspectors safely use FRP reinforcing bars in reinforced concrete construction with confidence, as well as manufacturers to safely market their product.
ICC-ES encourages manufacturers to comply with the most current codes to increase market acceptance. For more information about updating your product’s code compliance to the current codes, contact ICC-ES at 800-423-6587 or es@icc-es.org.
###
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To blindly accept an evaluation report can be irresponsible. Remember evaluation reports are a source of income for ICC and are based on information provided by the manufacture. This is not an impartial process.

Are evaluation reports used to bypass the code adoption process?

I give more credence to standards where an effort was made to get a diversity of opinion and to codes that have been formally adopted.
 
Mark K said:
To blindly accept an evaluation report can be irresponsible.
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That is true of NRTL Listing as well. NRTLs are for profit corporations. I have rejected Listed and Labeled products and equipment. Understand that the jurisdiction can base an approval on an ICC report or a NRTL Listing however, neither compels an approval. You can still say no.

If you do reject a Listed product, expect a shlt storm. Managers look at a Listing or an ESR as an insurance policy. No matter what happens, management can hide behind the Listing/ESR and feel safe from reprisal. If you stand in the way it becomes a contest between you and a phalanx of engineers. I have found that engineers detest arguing with a mere inspector. You have to pick them off one by one.
 
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