For chokers from single loop slings, you are making a noose on the leg
below the rung, and long enough slings so the tension is ok in them and
not too much compression force on the legs. 8' slings?
Not sure how your crane will be configured, maybe a multi sheave hook
for a 70T crane? Assume it will swivel since the wire ropes won't very
much. With long slings there is probably enough motion in them. Ask
how the crane will be rigged.
Grant KZ1W
On 10/12/2016 10:51 AM, StellarCAT wrote:
That's what I figured! Didn't use the term - didn't remember it at the
time but choker slings... wrap them so they 'grab' the legs equally
and thus it should be vertical. The hook will freely swivel correct?
So this hanging load can be turned by the guy putting the bolts in -
right? Its been a while since I last did it ...
g.
-----Original Message----- From: Grant Saviers
Sent: Wednesday, October 12, 2016 11:36 AM
To: Fred Keen ; StellarCAT
Cc: tower
Subject: Re: [TowerTalk] Lifting a pre-built section of tower using a
crane - how to strap it off
A good catch re managing the bottom end of the 60' tower assembly being
hoisted. I used a fork lift and sling at the bottom. A good crane op
can swing the boom to minimize the drag and load. Also, rigging to the
top with three slings for this much tower will have it truly vertical
and much easier for the tower man to join the sections. With 3 choker
slings on the legs there are very low loads on the rung welds.
Grant KZ1W
On 10/12/2016 8:19 AM, Fred Keen via TowerTalk wrote:
As you lift the tower, it was a lot easier for us having three men to
hold the guy wires away from the tower as it was lifted.
Have you given any thought to how you're going to move the bottom of
tower as the crane lifts it? We used a small front end loader bucket,
there is not a lot of weight involved but the bottom will drag the
ground until the point where the crane has the tower section off the
ground.
Fred KC5YN
On Wednesday, October 12, 2016 9:19 AM, R Morris
<robrk@nidhog.net> wrote:
The crane guy will know how, and usually pick up at the 60% point.
In your case, 40 feet, and a choker around the whole tower.
Sent from my iPhone
On Oct 12, 2016, at 10:06, StellarCAT <rxdesign@ssvecnet.com> wrote:
Ok,
Another question: so I have this 60’ long section of R55 with a
rotating ring at the 48’ point which will have guys hanging down from
it ... the weight is probably around 850#. The tower is laying with
the top closest to where the crane will be set up (probably 50’ away
from its nearest end) and the tower going away from the crane.
How do I ‘strap’ this for the crane to lift it?
I’m concerned that the rungs are not strong enough – their welds – to
strap around them ... do I somehow wrap around the legs using three
straps all going up to the hook?
Gary
K9RX
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