Non-contact lap splice question

[structeng24]

I have a situation where the spacing requirement for a non contact lap splice can't be met. Can I just develope the reinforcing on either side of a potential crack? Essentially provide 2x the development length?

 

[slickdeals]

You can provide ties over the lapped area and design it per strut and tie principles. Some information is available in this article.

 

[structeng24]

Thanks for the reply, although in the situation I'm looking at, I don't think I can place ties.

Going back to my previous question, could the reinforcing running in opposite directions be extended the development length past the point where the opposing bar is developed? so at any section, reinforcing would be adequately developed on either side of a crack.

 

[canwesteng]

Can you justify it with a simple strut and tie model?

 

[dik]

CRSI allows for non-contact splices... max distance between rebar is 0.2 x splice length with a maximum of 6". Preferable to use contact splices.

Dik

 

[MotorCity]

No. A splice length is different than development length. In a splice, you are trying to maintain continuity. Continuity can only be maintained if the bars are within a certain distance of each other. If the bars are too far apart, continuity is lost. Think of this extreme......if you provided the development length as you suggest, but the bars are 6' apart, the continuity is clearly lost.

 

[KootK]

Two additional points:

1) In some locations, such as NZ, they have provisions for this. I've seen it specified that the lap should be the normal lap plus 150% of the extra distance between bars.

2) My personal opinion is that you can do this in the plane of the thing but not out of plane. With out of plane non-contact lapping, you generate a bursting stress on the concrete that is problematic. I've seen research pointing to this issue but I can't say that I've ever actually seen an explicit code provision to this effect.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.