hairpin to resist thrus

huangyhg

hairpin to resist thrust
how does a hairpin resist thrust.  from a design example i have, the hairpin transfers the thrust into the slab, then slab to wwf which acts as a tension tie to the opposite hairpin.  this approach seems valid until i looked at our control joint detail.  the wwf is supposed to be discontinuous at the joints (not that it ever happens) which would invalidate that approach.  the only other approach i see is to use the friction resistance between slab and soil.  the only problem with that is geotechs say if a vapor barrier is present the c.o.f. is too small to be of any use.  
any thoughts?  does anyone have another approach using hairpins?  i am thinking about always using tension ties.
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the approach that you take depends on the amount of thrust that you are resisting. low thrust: use hairpins and wwf and/or friction. high thrust or vapor barrier: use ties.
the hairpins need to extend a distance past the the point where the wwf are cut. this way, where the hairpins end the wwf can pick up the force.
also, if you have isolated foundation, much of the thrust can be resisted by the soil on the sides of the foundation thru passive pressure.
thanks for your replys