FRP Systems for Strengthening Concrete Structures

[engsaso]

Hi everyone! i have a prestressed HOLLOW beam with shear cracks near to support, the owner have the idea to use FRP Systems for shear strengthening, BUT! the beam have stirrups steel grade 60 rebars size 4 (1/2" diameter) with s=4", then Vs = 336 kips, this arrangement exceeds ACI limits for shear Vs< 8*SQR(f'c)*bw*d = 211 kips, is possible to use FRP Systems for shear strengthening ???

THANKS!

 

[STrctPono]

I am unsure what a prestressed hollow beam looks like. Perhaps a quick sketch would help. FRP can increase the shear capacity but in order to be effective, you will need to be able to drill composite anchors through the web of the beam to anchor the tops of the CFRP. Not sure how that would work with a hollow beam unless we saw the beam cross section. Can't help you on the discrepancy of the capacity vs. the demand. Are you sure they are shear cracks? Are they present in all the beams?