On 11/9/13 9:28 AM, Michael Tope wrote:
Thanks, Jim:
Both AB Chance-Hubbell and MacLean Power Systems sell them for utility
applications:
http://www.hubbellpowersystems.com/anchoring/expanding/
http://www.macleanpower.com/products/item.asp?ITEM_ID=2087
Except for the W8JI site, I have never seen any mention of them as an
option for ham radio towers.
I noticed that one of the entries in the table you linked to showed a
depth of 73ft! I can't imagine that would be the requirement to get a
good anchor, so perhaps that's how deep they had to go to get into the
soil conditions that are listed.
yeah, that's weird.. Maybe it's because "dig a hole and fill it with
concrete" is something one can do with pick and shovel and little training.
Driving the real deal anchors 20 feet in with hydraulics is a
specialized operation. Most structural engineers know about these
things, so if a ham was in a situation where they were talking to a PE,
and the screw in anchor was appropriate, they'd mention it.
They're used a LOT for utility poles, which often have enormous side
loads. The same hydraulic rig that runs the auger for the pole can be
used to drive the anchor.
When I was in the EFX business, there were two companies in the LA area
who essentially did ALL of this kind of work for everyone. Boudreaux or
something like that. You'd tell them the pull out load you needed, and
they'd show up with their truck and drive the anchors (e.g. for our 50
foot high tornado rig out on Ave E in the high desert)
I don't know about the 70 foot depth. I know they've had terrible times
with the anchors for the retaining walls on the 405 widening project in
Sepulveda Pass. They're over 100 feet deep, and still pulling out. I
think those are "bore hole, insert anchor, then grout" type anchors.
The "rock" there is just not very "rock like" (and it's water
saturated.. there are artesian springs everywhere
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|