Keith eMail wrote:
> re: tower base in concrete
> In my experience you need to coat the galvanized tower with spray automotive
> type under coating, tar, or
> something to protect it from the acidic concrete.
Concrete is definately not acidic. It is basic like caustic.
> I have seen several Rohn
> 25 towers that rusted
> off right at ground level because they weren't protected from direct
> contact.
This was probably due to water not being able to get away from the
interface. If the top of the pour is not raised and crowned to keep the
water from collecting around the legs which happens even with a flat
top, then the legs will rust at the interface. The same is true if the
legs do not extend all the way through the concrete and into the crushed
ruck underneath to properly drain, or if they become plugged.
Another point is it is not a good idea to mount the tower base this way
in swampy land. IOW if the area has been filled over swampy land, the
water is likely to be highly acidic.
> Galvanized tower and
> concrete don't really play well together over the long term. I have since
> noticed that commercial grade
> galvanized road culverts have a tar like coating for, I suppose, the same
> problem. Just my observation.
>
Admittedly there are conditions where galvanized and concrete do not
play well, but I've never seen a coating used on them up there in the
frozen North. They state redid and widened a large portion of M20
between Midland and Mt Pleasant (~20 miles). I did not see a coating on
any of the many hundreds of galvanized culverts from 12" to over 6' in
diameter. Ours was not done either, but that was nigh onto 15 years ago.
73
Roger (K8RI)
> Keith
>
> ------------------------------------------------------------------------------------
>
> Subject: Re: [TowerTalk] Tower Base In Concrete
>
>
>
>> Steve:
>>
>> First of all why do you want to attach the tower section to
>> the rebar. This would serve no useful function unless you are
>> trying to hold the section up while you pour the base. Just
>>
>> (clip)
>> doesn't require a rebar cage as the buried section of the
>> tower functions
>> as rebar.
>>
>> What tower are you installing? I am in the process of
>> installing a Rohn 45
>> and Rohn 25 tower.
>>
>>
>> 73 Mark N1UK
>>
>>
>>
>> ----- Original Message -----
>> From: "Steve Bagley" <n2mai@arrl.net>
>> To: <towertalk@contesting.com>
>> Sent: Friday, 23 April, 2010 3:06 PM
>> Subject: [TowerTalk] Tower Base In Concrete
>>
>>
>>
>>> I am installing a base of my tower directly into the
>>>
>> concrete. If I place
>>
>>> a layer of sand or crushed rock at the bottom of the hole
>>>
>> for drainage,
>>
>>> should I place the base directly onto this rock for
>>>
>> drainage?
>>
>>> (clip)>>
>>> Steve, N2MAI
>>> _______________________________________________
>>>
>>>> (Clip)
>>>>
>
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