>My question. How do you dismatle a tower of questionable condition? Is a
>crane the only way? Also if you have ever hired a crane for such work,
>what is the going price for a crane. Seems to me it would be outragious,
>like $1500 for a few hours. I may be low.
>
>Just curious how those of you who scraf old towers from commercial sites do
>it?
Kevin,
The old timers in the tower field walk away from derelict towers--that is why
they are old timers!
Cranes can work--but when pulling something from the middle of the roof
of a building it may take more crane than you are prepared to pay for.
Prices can vary a lot on size (of course) but also on region of the country.
If you are in a building boom you may just have to pay the going rate,
but if the local economy is slow you may be able to negotiate a pretty
good deal.
With a crane it only takes a few minutes if the preperation is done properly,
but the tower has to be in pretty good shape to make it worth while to
pay a crane to come in. At $50 for used Rohn tower on the ground can you
afford to pay more than an hour of total time (portal to portal) for
questionable
tower. Probably be about $200 per hour for a decent crane with enough
reach to do a roof mount. With good prep and fortunate location of a crane
company to minimize drive time, you might be able to spend less than the
value of the tower--if it is good tower.
The crane needs to be attached about 2/3 of the way up--meaning that
you have to climb to that point but is it safe? Or you have to ride the
hook, but OSHA had seriously limited dare devil opportunities. Typically
the only cost effectie way to take down Rohn 25 is piece by piece with a
gin pole. You had better be SURE of the condition of the guys and
anchors. I hear about more tragedies with little towers being dismantled
than I do with bigger towers being raised.
Temporary guys can provide a large increase in confidence, but you may need
to use alternate anchor points if the existing ones are marginal. The most
common major mistake made by inexperienced tower people in a project like
this is to assume that the tower is self-supporting below the last guys. In
most cases it isn't and you will need temp guys at 20 ft if the tower is
now guyed
at 30 ft. That last 20 ft can usually be walked over with a couple of
helpers.
Maybe you can get the owner to actually pay a few bucks to have it removed--
the tower being a hazard and all. That will help with the crane bill if
you can go
that route.
But with the tower as you describe I would normally walk away--unless I really
wanted to do it and then I would take a lot of precautions--temp guys at 30
and 60
in addition to the existing ones of unknown condition.
Bottom line--if you do it--inspect it very thoroughly and take your time to do
it right. One local accident a few years ago was where the guy taking down
the roof mounted Rohn 25 thought that the last two sections would self support
from the below the bottom set of guys. He went over with the tower and was
only that 20 ft up--but hit his head on an air conditioning unit and it
cost him
his life.
Good luck!
John W0UN
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