FRP - Strengthening around slab opening, HowTo?

[SilverBeam75]

Hi,

Not very familiar with the FRP (carbon) plies. My project is to cut several holes (approx 20"x6") in an existing concrete slab (8" thk) with 15M @ 12" o/c ea. direction.

I will need to add FRP plies around the hole. But what is the methodology, how to approach such problem ?

If I consider that the section that I remove is similar to a beam 8x6 and 20" long and I evaluate the Mu of that beam and then I will figure out what FRP section is equivalent to that beam ? And apply it on the side of the hole. Is that O.K.?

How long the extents of the plies should be ?

thank you for any help,

 

[Ron]

Contact Sika or one of the other carbon fiber overlay producers. They have plenty of information and details to do what you want.

 

[abusementpark]

Is this in a commericial building?

If so, I believe there are fire-rating issues associated with the epoxy bonding agent.

 

[rowingengineer]

you can clad the FRP with fire check or similar to get fire rating.

The method for working out the amount of FRP, is not a simple replacement for the reo, you need to check strains ect. As ron says start with sika, then come back if you need some more help. Also Rapt handles FRP these days.

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[abusementpark]

Also,

ACI 440.2R-08 is the design guide you will want to reference.

 

[hokie66]

Why do you think you need to reinforce the holes? Have you done an analysis that shows it it necessary? They are quite small holes, and depending on where they occur, may not require any reinforcing.

 

[BAretired]

Agree with hokie that you may not need to do anything. On the other hand, if the holes are adjacent to columns in a two way slab, you may want to think twice about doing it at all. FRP will do nothing for shear strength.

BA

 

[SilverBeam75]

Thank you all for helping. I've done some research and you are right, it is not that simple as I tought ;-)

I found a great design guide with several examples and the slab opening is in it.

For those who are interested, see "FRP Rehabilitation of
Reinforced Concrete Structures" on

http://www.isiscanada.com/manuals/manuals.html

see manual 4