FRP on slabs to reduce long term deflection

[structSU10]

I am trying to find information about using FRP strips on the compression side of a two way slab, such that it can be relied upon to reduce long term deflection.

I highly doubt the FRP strips will help restrain creep effects in the concrete, and don't think they really do anything in compression for that matter. Does anyone have information on something like this? Either to show it does help or it doesn't?

 

[rapt]

I would think it usefulness in deflection control as 'compression face" reinforcement would be minimal!

 

[Triangled]

there's been quite a bit of work done with frp on glulam beams, I think out of the University of Oregon, on both the compression face and tension face of beams, such as cantilevers. But, if I recall correctly, it mainly contributed to strength, and not so much stiffness.

 

[MacGruber22]

My thoughts are: two things help deflection, increase MOI or add prestress force. Strips of FRP are passive and contribute minimally to an increased MOI. If you have means to do so, I would consider external post-tensioning system.

"It is imperative Cunth doesn't get his hands on those codes."

 

[Ron]

Agree with others. I would not use FRP for creep control or compression enhancement.

 

[Stenbrook]

How would putting FRP on the compression side of a slab resist creep? FRP itself is subject to creep so it probably is not the best for resisting creep. Also, FRP has essentially zero capacity in compression.If you were going to use FRP, I would apply it to the tension face. I have heard of FRP being prestressed in a strengthening application. Not sure exactly how it is done but it may be something you could try and research.

 

[structSU10]

That's the issue. It was 'recommended' that this could be done to help long term effects (we are doing a pseudo peer review of this recommendation). I don't see how it could possibly work that way, and it seems no one else has seen this be done either. Obviously it is an expensive undertaking, and something like this that won't help is a huge waste of money and effort.

 

[Stenbrook]

Have you looked at the ACI440 documents? Those provide a good outline on FRP strengthening and design applications.