rebar development length in concrete restoration

huangyhg

rebar development length in concrete restoration
i am involved in a project where we are restoring concrete spandrels or as i hear them refered to as "eyebrows."  each floor line of a multistory building the concrete has deteriorated (water intrusion leading to rebar corrosion and concrete spalling).  the question is, in making these repairs and splicing areas of new rebar where the old has greatly deteriorated, we must break into sound concrete in order to establish development lengths.  the aci code is very complicated to this matter for a contractor in the field.  plus, i would want to limit the amount of damage to sound concrete in order to establish a development length.  any ideas or rules of thumb out there?  thank you kindly for any information.

check out our whitepaper library.
i think it depends on the condition of the reinforcing more than anything else.  you have to break back far enough to connect to undamaged reinforcing.  you may want to consider some type of reinforcing bar connectors, either welded or mechanical, to limit the breaking out of sound concrete.
the "eyebrows" sound like architectural rather than structural elements.  in restoring them, probably the most important thing is to provide protection so that the condition doesn't reoccur.
i am not a fan of patching a beam, eventhought it has a funny name. a spandrel tends to rotate (twist), thus breaks the patches again. shore up, and rebuild the beams.