huangyhg

epoxy vs. wedge anchors?
hi all, what is the rule of thumb in choosing to use either an epoxy anchoring system or a wedge anchor? in my limited experence it appears wedge anchor would be used in overhead or vertical situations and epoxy anchors on horizontal applications. this is for air diffuser supports (low pullout forces) within a waste water channel (12 ft deep).
thanks
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i use adhesive anchors in situations where a mechanical anchor cannot be used, because it is too close to the edge of the concrete. otherwise, they have similar values.
daveatkins
besides close edge distance situations, i use chemical anchors for vibratory situations like machinery hold downs. otherwise, it's mechanical.
another option is simpson's titen hd anchors.
it's a toss-up. i prefer epoxy anchors because it's too easy to drill a bad hole and totally mess up the capacity of the wedge anchor where a slightly oversized hole for epoxy wouldn't hurt as much. the con is getting the epoxy hole cleaned properly. i think if you ask for special inspection you'll have done the best you can.
i don't know if it's still the case, but 6 years ago or so, the epoxy (or other non-epoxy adhesive anchors) typically had undergone better testing and had their paperwork more in line that they would be accepted by a building official. i personally try to avoid using wedge anchors unless loads are small and vibration isn't a concern.
for wedge anchors you have to be careful if you are working in cracked concrete. i'm not positive but i think hilti is one of the few (if only) manufacture to address this case for the new codes. i prefer epoxy, ran into too many oversized holes when workingwith wedge anchors.
if you expect to be installing the anchors in the cold (its getting to be winter now), if using chemical adhesive make sure it can still cure at lower temps. usual lower bound limit is about 40 deg f. i don't think any mech anchors have a temperature limit during install.
if you expect to have high temps during service life of the anchor, if using adhesive, suggest using a higher sf because depending on the mfgr the adhesive can lose strength and stiffness over time when heated. mfgrs catalog should tell you more.
if you have moisture or water in the holding substrate, also be especially careful if specifying an adhesive anchor. some of the adhesives out there are sensitive to moisture, others actually need it present to cure.
as other posters have noted, i usually do not use a mechanical anchor if its holding something that vibrates, because the anchor can be rocked loose over time and lose holding power.
i hate wedge anchors. half the time they are crooked, or the hole is too big, or the sleeve protrudes, or something or other.
i also use adhesive anchors when attaching structural elements to a fire wall. i have been told the epoxy melts in a fire, allowing the structure to collapse without pulling the fire wall down.
daveatkins
go to either simpson strong-tie or hilti websites. they will explain all kinds of info for you on these subjects.

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