Traditionally HILTI tables indicated the required embedment lengths to develop either the yield strength or the tensile strength of the rebar. These published embedment lengths were substantially less than ACI embedment lengths for CIP rebar. Why do we now need to embed post-installed rebar for ACI embedment lengths as opposed to the older tabulated values?
David,
Until 2013, post-installed reinforcing bar was not officially regulated or included in the acceptance criteria. While it was not in the acceptance criteria, it was still used for this application. Tables were developed based on assumptions and the provisions provided for anchoring. When post-installed reinforcing bar was amended to the acceptance criteria, the development length tables were recalculated using the appropriate provisions. This may account for the difference in length you noticed. Please see Section 6.0 of the attachment for further back story.
Lisa
