ACI Appendix D - Substitute larger Anchor for cosmetic reasons

[Dazed_and_Confused]

Someonewhat silly questions:

We have a pipe support that sits on a concrete pedestal that is being designed to take a very small lateral load (150 lbs). Our support has 2 anchors and was detailed for a 3/4" anchor. (1/4" bolts would easily handle the load but for cosmetic reasons I'd like to use a 3/4" bolt but the edge distance requirements shoot up from 2.5" to 6". The support was intended to be 6" thick and now has to shoot up to 12" thick (it holds a single 4" pipe!)

The question comes down to, if a smaller bolt works is it possible to substitute with a larger bolt as long as the smaller bolt design capacity works? Common sense and from my understanding of Appendix D tell me yes but curious if I am missing something here?

 

[STrctPono]

Common sense will tell you yes.

If memory serves me correctly, you can reduce your edge distance requirement if you reduce your installation torque values. Is this post installed or cast-in-place anchors? Either way, both do have a torque value associated with them that you can reduce.

 

[canwesteng]

6" seems too small for a pedestal anyway. The problem with common sense, is that you are deviating from values determined from empirical testing and not some theoretically sound failure mode (as opposed to putting steel bolts close to the edge of a plate). If anything goes wrong it'll also be the first thing another engineering points to.

 

[Dazed_and_Confused]

All good points. Upon further study I had been looking at post installed expansion anchors with an associated torque and expansive force.

All clear now thanks for the input!