[TowerTalk] Digging a 5'x5'x8' tower footing

[RICHARD SOLOMON]

If my math is correct (only took off the left shoe), the LM-470 requires a base
3.5' X 3.5' X 7.5'. that equals a 4' diameter by 7.5' deep hole.
Now I need to talk to the Tower folks and see if they would sign off on that.
 
There is a local Tree company that I also need to chat with.
 
73, Dick, W1KSZ



> Date: Mon, 12 May 2008 13:53:37 -0700> From: jimlux at earthlink.net> To: w1ksz at q.com> CC: towertalk at contesting.com> Subject: Re: [TowerTalk] Digging a 5'x5'x8' tower footing> > RICHARD SOLOMON wrote:> > Let me toss this out for consideration. I too have the situation where I need> > a large hole for an LM-470 base.> > > > I thought about contacting a "Tree Planter" and getting him to use his big> > Auger to bore the hole for the base. I don't think it makes much difference> > if the hole is round or square as long as the same amount of concrete is> > used.> > > > Or am I totally off base here ??> > Nope.. you're right on base. here in Southern California, a lot of > structures (light posts, freeway signs, roller coasters, etc.) get > installed on what are essentially vertical reinforced concrete columns. > Drilled out with a BIG auger, rebar cage dropped in, concrete poured, etc.> > Your engineer can tell you what diameter and depth works for your loads > and soil conditions. A lot of times, deeper and smaller in diameter > works better than big and flat (it doesn't cost much more to drill a few > feet deeper, once you've got the machine there and set up).> > A fairly common scenario here is upgrading traffic signals. They'll > jackhammer out the sidewalk on the corner, leaving a hole inside the > existing curb about 4x4 feet. Drill a 3 foot diameter hole 20 or so > feet deep, then set rebar and fill with concrete. Then, the lamp > standard gets bolted on top. These have huge canteliever loads (imagine > the horizontal crossbar spanning 3 or 4 traffic lanes holding up the > signals)> > > They can do all 4 corners in a morning.> > For smaller jobs, they've got machines that can do 2 foot piers on a > small skid-steer type carrier (think crawler drill for blasting) that > you can get through a 5 foot wide gap between house and fence. I don't > know how deep the little machines can go, but 10-15 feet is plausible, > but you might have to put an extension on the shaft.> > > > Jim, W6RMK