Hi Grant,
Indeed it was about one ring - and that ring is near the top (48' level of a
60' stick) ...and determining the COG isn't that difficult at all using sum
of moments. It should be pretty straight forward. Assuming he booms out as
he lifts to keep it on a radius, which is the key, there will always be a
force at the end pushing it down in to the ground so again assuming he booms
out as he lifts on a radius it should stay planted. Not that difficult I'd
guess for an experienced operator. I've seen them place something within an
inch of where you need it at a distance of 100' from where they sit ... that
stated I will try to get something under the legs as it will more than
likely get dragged at least a little.
Gary
K9RX
-----Original Message-----
From: Grant Saviers
Sent: Monday, October 17, 2016 10:39 PM
To: Steve Maki ; towertalk
Subject: Re: [TowerTalk] Legs of a 60' piece of tower being dragged while
being lifted
Since my largest tower went up with a commercial tower company who
builds 400' plus towers, and who required the base be managed, I would
say there are definite disagreements about this. When lifting sections
with rings off supports, it can't be done safely and reliably, no matter
the skill of the crane op. A plain stick of Rohn 25/45/55 is a
different animal. Note the thread origin is about tower sections with
rings already mounted.
Grant KZ1W
On 10/17/2016 18:55 PM, Steve Maki wrote:
On 10/17/2016 11:53 AM, john@kk9a.com wrote:
The weight is irrelevant. A skilled crane operator can move the boom as
it is being lifted leaving the section on the ground as a pivot point.
Of course if someone wishes to build a slide or use a loader to move
the base as it is being lifted that is perfectly fine, but I won't be
doing this.
John KK9A
I agree. A good operator has no problem at all with this scenario, as long
as the crane is sized properly and can be positioned properly.
It's just a non-issue.
-Steve K8LX
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