I rented a skid steer Bobcat with a 500 lb hydraulic hammer chisel on
front as an implement to square off excavations in sandstone that broke
the 4 ft bucket off the track hoe. Fun and i interesting toy to
operate. Highly recommend it if you have to dig a hole and find too
much rock.
Patrick NJ5G
On 4/15/2015 1:45 PM, Steve Jones wrote:
Kent-
Sounds like you're on our Butano Sandstone Formation here in the Santa Cruz
Mountains.
When I put up my UST HDX-589 I had the same soil conditions. I hired an
outfit with a small excavator to dig the hole square with vertical walls.
All the backhoe operators said they couldn't dig vertical walls and would
need to dig a big pit and form up the concrete foundation within the pit.
That's not how the structural engineer designs these foundations, which
depend on the friction of the concrete with the "undisturbed soil" on the
vertical walls to provide part of the resistance to overturning moments.
The excavator operator had a jackhammer attachment for his machine that
broke up the really hard sandstone.
If you're in the Bay Area, call Andreini & Sons in Half Moon Bay. They did
a great job for me.
GL es 73!
Steve
N6SJ
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Kent
Olsen
Sent: Wednesday, April 15, 2015 8:43 AM
To: TowerTalk@contesting.com
Subject: [TowerTalk] Sand Stone
Hi all
I am putting up a used US Tower HDX-572MDPL. I started digging the hole (yes
by hand) and got about 2 1/2 feet down and I hit sand stone. My neighbor who
has a back hoe and has done a lot of digging in my area says he can dig the
hole. My question is will the sand stone be much more stable than just the
soil? Is there any thing I need to do because of the sand stone as far as
the foundation?
Thanks
73
Kent
K6DKO
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