Section R611.9.1.1 in the IRC indicates that "J or L-hooks shall not be used where the connection details in these figures are used". Well I'm am doing something SIMILAR to the figures (not exact), but I'm confused why we can't use L-hooks for our PIP concrete walls if we use the prescriptive method in the IRC to design the house. Does anyone know WHY J and L-hooks aren't allowed in PIP walls only? These are probably the most common type of anchor bolt that I see. They seem like they would be "better" than a headed bolt as anchors. This would basically apply to all ICF houses that used the IRC tables for design. Anyone?? Thanks!

OK, found a good discussion on it..... http://www.eng-tips.com/viewthread.cfm?qid=256700 Guess I kinda answered my own question again. :-)

Is it because of the asymmetry of the hooks that they tend to fail?

Posted By narcszm on 10 Dec 2011 06:42 PM
Is it because of the asymmetry of the hooks that they tend to fail?

I think it is based primarily on theoretical failure based on calculations and assumptions rather than in-service failures of L or J type anchor bolts.  In theory, under enough tensile strain, the L or J hook will straighten out and put out of the concrete. 

I'm sure there have been documented in-service failures under extreme loads or due to poor installation (i.e. wet setting bent anchor bolts after the concrete has already begun to setup and not getting good bonding to the bolt), but I'm not aware of conditions where bent anchor bolts "tend to fail" if installed properly.

It's because of the way they bend them. The sharp bend weakens the metal, and it will break when stressed at considerably less than their tensile capacity. I'll use them for sill plate anchors, but for the tie-downs, high-strength bolt with an oversized washer.