I mean no disrespect to any one, but I get a queasy feeling any time I
see engineers making changes that require improvisation, be it
mechanical, electrical, or chemical.
I worked in the chemical industry from a technician to a degreed CS
professional.. I've seen some pretty spectacular mistakes be engineers
and project managers in all of these fields. Fortunately no one was
killed, but some were pretty well banged up, including one guy blown
through a blow out panel and traveled another good 60 feet. I've seen
grounding straps vaporized with enough force to bend 7 foot tall X 3 ft
wide steel doors of 1/8th thick steel with 2" shoulders and rolled edges
to bend those doors 2 feet in the center and it was loud. I've seen
people go flying after chemical residue detonated, but that stuff was
all proprietary. All I can say I saw it, it was spectacular, and no one
was killed.
That no one was killed or seriously injured was most likely due to the
stringent safety regulations and protocols we had to follow. There were
some short hospital stays, damaged hearing, and a couple cases of
extreme nerves. I actually felt safer as a tech working with the stuff
than a guy with a degree that had to be around it.
As hams, be it climbing, or construction, no one "forces" us to follow
the rules. We can wing it, or best guess, but often we'd do better to
ask a professional.
Were it me, "and it's not": First, I'd make sure the holes were deep
enough to provide the required holding strength. The larger the hole in
the base material, the weaker the holding strength, even with bushings.
"IF and I emphasize the "IF" the amount and depth of the base material
is sufficient for strength, AND the concrete mix is strong enough
(depends on concrete, water, and aggregate ratio as well as cure) I'd
make, or have made some sufficiently long threaded bushings to provide
the desired clearance. I would present these figures to a construction
engineer for his blessings. I'd have sufficient confidence in my metal
work, but would seek outside qualified help for the concrete and holes.
As long as we have bushings, I'd weld the bottom end of the bolt into
the bushing.
Those holes have to be a depth to provide the required strength with
that diameter hole! THEN the epoxy has to be strong enough with the
required clearance in a hole that big.
73 and good luck,
Roger (K8RI)
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