[TowerTalk] New Tower Old Base

[John Lemay]

About 15 years ago, I purchased a larger crank-up mast with a new base
plate. Of course, the original holding down bolts were not in the right
place for the new base.

The old ones were cut off flush. Four new holes were drilled (no easy
matter) to take resin fixings. These were "Rawlbolt Chemfix", for UK
readers. From memory they only sit about 6 to 8 inches deep in the concrete.

They have been absolutely fine for my 45ft mast.

I took this route after discussing these fixings with colleagues at work.
Epoxy anchors are used for holding safety fences and parapets on bridges, so
I figured they would be good enough for me.

John G4ZTR


-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Andy GD0TEP
Sent: 09 February 2011 21:32
To: towertalk at contesting.com
Subject: Re: [TowerTalk] New Tower Old Base

I know of one local here who change the type of tower from a fixed post to
one that needed a base plate.

 

He cast a small block of concrete right next to the original block, and in
the new bit he included two new studs for the new base, but he also drilled
two holes in the original concrete and used resin type fixing for two new
studs. The resin was in a glass tube, and part of the instructions for
drilling was to make sure that ALL of the dust was vacuumed out and the
newly drilled hole was dry and clean.

 

He was sceptical prior to all of this, but did many calculations and decided
to go with the resin. That was circa 10 years ago and it's still OK. This
was for a un-guyed tower with a tribander, and rotary dipole, plus a string
of dipoles for low bands.

 

73,

Andy

http://gd0tep.com

 

From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Michael Goins
Sent: 08 February 2011 23:05
Cc: Towertalk
Subject: Re: [TowerTalk] New Tower Old Base

 

I can't imagine that being a good idea.

The base that was original extends into the concrete via a welded cage or
the attachment to other tower (which does the same thing) and is then bolted
to the tower. I would be surprised if you could drill holes deep enough to
manage the stress of windloading with just a simple bolt replacement into
epoxied holes.

Mike, k5wmg
Pipe Creek, Texas
A thousand words a day. Five days a week. For life.




On Tue, Feb 8, 2011 at 4:54 PM, Richard Zalewski <dick.w7zr at gmail.com>wrote:

> I will be upgrading my tower and will be using my existing base.  This
will
> require drilling the existing concrete base and epoxing in some new bolts.
> I would be interested in exchanging some emails with someone who has done
> this.
>
>
> --
> Tnx es 73
> Richard W7ZR
> www.w7zr.com
>
> *WHAT HAVE YOU DONE WITH WHAT YOU HAVE BEEN GIVEN?*
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
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