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Carbon Armor wall reinforcing

Discussion in 'Residential Foundation Codes' started by skipharper, Dec 19, 2011.

  1. skipharper

    skipharper Registered User

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  2. mjesse

    mjesse Sawhorse

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    A contractor here has installed some similar products. Seems like a high-tech band-aid to me.

    mj
     
  3. Mark K

    Mark K Platinum Member

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    It appears to be similar if not the same as the FRP systems used for concrete repair.

    This system effectively provides some interior wall reinforcing to compensate for a lack of reinforcing in the wall at the time of construction. While soil expansion may contribute to the problem in some cases I will suspect that in general the pressure from the soil is higher than assumed thus causing problems.
     
  4. RJJ

    RJJ Platinum Member

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    Two issue present in the wall shown. Step cracks and bed line crack. I agree with above it is a band-aid. The product shown have not used or inspected. The bottom line is what is the cost of the band-aid in relation to fixing the wall properly?
     
  5. Frank

    Frank Sawhorse

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    This reinforcing technique is a tool in the engineer's toolbox for fixing certain types of foundation problems--a bowing wall that has adequate top and bottom anchorage but the wall was constructed too thin, lacked adequate reinforcing or the soil was different than assumed at construction.

    In Virginia it would require sealed plan.

    Is this being considered to deal with earthquake damage?

    Many basements have been built with prescriptive code provisions that do not work for certain soil types. Other changes that can trigger these types of failures in walls that were prescriptive code compliant (CABO/IRC) at construction include regrading that adds soil pressure or the installation of an irrigation system that keeps the soil wet. We had one fail here that was constructed to code but the combination of clay soil and irrigation overstressed the unreinforced wall and put the front yard in the basement.
     
  6. RJJ

    RJJ Platinum Member

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    Yes Frank I understand the toolbox, but it is still a band-aid and at some point the wall will need proper repair or replacement. All the conditions you listed including walls built to code I would agree with. However, my experience having replaced many a wall on both sides of the counter is it is still a band-aid.
     
  7. Mark K

    Mark K Platinum Member

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    This will not reduce any existing bowing and in fact you can expect additional bowing untill the carbon fibers are stressed. You might also want to consider the addition of fireproofing on hte added carbon fibers.
     
  8. Keystone

    Keystone Sawhorse

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    As pointed out, bandaid. The product can bring temporary relief but not rectify the underlying cause or the unseen damage on the opposite side of the wall...
     
  9. Frank

    Frank Sawhorse

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    In some ways this is similar to the stars you see on the outside of many old brick buildings with swayback roofs or moderately bulging walls. These stars were installed as washers for the through bolt rods that went from one side of the building to the other.

    The rods accross the building were a popular fix for spreading walls where the ceiling rafters were not providing adequate rafter ties in the 18th thru early 20th century, many of which are still holding buildings together.

    Reinforcing the inside of a wall that is bowing can stop the damage from getting worse (after it takes up tension with minimal additional movement).

    This is not a fix to good as new but a way to stop it from getting worse and keep the structure habitable.

    In most applications fireproofing would not be applicable in nonrated construction.

    Is jacking up the structure, excavating, removing and replacing the wall with a new footing and wall with adequate reinforcing and backfilling with drained granular backfill the ideal fix?--yes

    But in many applications strapping the wall with this type of product or anchoring steel beams to the floors above and below will be alot more cost efficient, does not tear up the landscaping and permits decades more service from the building.

    Think of it as a beat out fill and paint fender repair as oppossed to replacing the crumpled fender. It may not be as good as new but it can be alot more affordable.

    This product does have the limitation that the top and bottom of the wall have adequate latteral support.
     
  10. iggentleman

    iggentleman Bronze Member

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    A contractor asked us about using that product on a bowing masonry wall a few months ago and we rejected it for that reason. Instead, we had them brace the wall with 2" steel angles attached to continuous angles at the joists and slab, and treated the problem on the outside by rerouting roof drains and improving drainage.
     
  11. mmmarvel

    mmmarvel Moderator

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    Slightly different application but ... at the airport we are working (okay I'm working) on the renovation of our parking garage (it's approximately 35 years old). As with any renovation project, when you open up something (could be anything, a delaminated parking slab, a column that had concrete that was showing some sort of problem, etc) you often find more than you bargained for. In this case we have some corbels on some columns which support some bridges that go from a helix (the concrete structure which cars are able to circle in an upward motion to reach the various levels of the parking garage) to the parking garage itself (where there are opposite corbels to hold the other side of the bridge). Some of these corbels have been shown to be weaker and/or lacking in the strength needed to support the bridge and the cars (makes you wonder about the last 35 years). Anyway, on those questionable corbels we have been wrapping the corbels with the carbon fiber wrap, all per the consulting engineer. Again, this application is certainly different than yours, but in my own way I can relate.
     
  12. Daddy-0-

    Daddy-0- Moderator

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    Looks like a band-aid to me as well. This may be a contractor trying to make a quick buck off the earthquake insurance $$. Roll it on...cash the check....next!
     

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