masonry rebar lap length - any news

huangyhg

masonry rebar lap length - any news?
hi all
just wondering if there have been any new developments regarding the lap splice length of rebar in masonry?  to this day, every job i have contractors telling me i am nuts with the lap lengths i specify, which are calculated by that crazy aci 530 equation.
thanks
andrew
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you should stick to what you are willing to stand behind.  i'm not that well versed in the masonry code, but it could very well be that all the recent code revisions have crept into it as well.  we've all had to adapt to extensive revisions over the last decade.  maybe you are just dealing with people who want to do it the way they learned back in the old days.  unless you find something better, i suggest telling them you are only designing by the current code.
you are legally responsible to follow the adopted code.  that makes the decision easy, as far as what to do, though it may not be what we like or want.
i agree you are responsible to follow the code.  however, it is possible that new research or newly released codes/standards may contain different requirements, which are not yet adopted by the current code.  it is also possible in these cases to obtain exceptions to the current code by the building official based on this new information.
i was simply asking if anyone knew of any knew codes which have different requirements than the older codes, like say the 2004 fbc or 2000 ibc.  for instance, if the masonry society had recently released a position paper stating that they recommend x number of bar diameter lap, that may be good enough for the building official.  contrary to popular believe, the codes are not carved in stone.  there are always possibilities to modify the code, if you can show that it is appropriate to do so.
check aci-530-05 equation 2-9, development of bars in tension and compression.  the previous code requirement for lap splices was different and may be causing the confusion.
aci 530-05 results in approximately 20% to 25% shorter laps than aci 530-02 & ibc 2003.  this ends up being shorter than 48 bar diameters for #5 and smaller bars, but longer than 48 bar diameters for larger bars.