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FRP uses for bridge repair/rehabilitation

FRP uses for bridge repair/rehabilitation

FRP uses for bridge repair/rehabilitation

I'm curious what other's opinions are about using FRP for repairs to concrete bridges. I have a bridge rehab under construction that involves repairing the ends of some PC beams and wrapping them with carbon fiber reinforced polymer. Yesterday I saw the repairs they have done so far (only a small portion) and was not impressed. I was able to tear off some of this stuff with my bare hands. This will obviously have to be done again. There is a very detailed spec for this stuff, but I'm not sure if anyone is reading it. The spec says to perform 2 direct pull-off tests for every 300 sf applied in accordance with ASTM D7522. From what I have read, an acceptable test occurs when the FRP is pulled off and some of the concrete it's bonded to pulls off with it. That definitely can't happen if I can pull it off with my hands!

I'm trying to figure out if what I'm seeing is just related to poor work and ability or something else. I have seen it used quite a bit to wrap reinforced concrete columns, and that seems to work quite well.

RE: FRP uses for bridge repair/rehabilitation

For FRP applications to RC columns (usually confinement) the FRP is "contact critical", however, for most other FRP applications the FRP is "bond critical", and that is where particular care has to be taken to surface prep of the substrate and install of the FRP to avoid delaminations.

Usually the spec will detail the acceptable area of defects (X in2 in Y ft2), and methods to repair or remove and replace the defects.

I have been involved with FRP since 1998 for buildings and bridges and have seen some absolutely crap installations. Given the current large number of suppliers/manufacturers and the often inexperienced field crews who undertake the prep and installation I am surprised there are not more defects reported.

Exterior installations can be challenging too with "out gasing" of the substrate if there is a significant substrate temperature rise over the epoxy cure time.

RE: FRP uses for bridge repair/rehabilitation

Sounds like I should be on the lookout for bad work. What effect would an air temperature in the mid to upper 90s have on the installation?

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