On 7/5/2011 11:46 PM, chas wrote:
> On 6/29/11 8:35 AM, Eddy Swynar wrote:
>> Hi Mike,
>>
>> The DELHI-brand self-supporting tower instructions here do not
>> specifically reference the necessity of coating the in-cement leg
>> extensions with ANYTHING...
>>
>> They DO, however, explicitly state that you must install long bolts
>> through holes in the extensions at the bottom, to ensure that the things
>> won't somehow extricate themselves from the concrete.
>>
>> ~73~ de Eddy VE3CUI - VE3XZ
> Eddy...
>
> ok, can you say that again? my understanding is that he is taking a 10'
> section of 45 and putting 5' of that into a hole and then filling it with
> concrete.
> Same thing I did with a 25G. Btw, I do suggest that room be left for
> drainage of water - 1. put a 6" layer of large aggregate in the bottom of the
> hole and that allows condensate, etc to drain out of the vertical tubes and
> into the aggregate 2. also drill a couple of 1/4" holes in each leg about 2"
> above the MOUNDED concrete top (to encourage rain runoff) to allow water to
> drain out of each tube.
To quote the ROHN Catalog: Do not drill out bolt holes that are
undersize as it will remove the galvanizing and leave bare steel exposed
to the elements. Use a taper pin (drift punch) to enlarge the holes. I
would expect this applies to drilling holes in tower legs as well.
The need for extra work at the base is highly dependent on location.
If you do drill holes, make certain they are well water proofed.
73
Roger (K8RI)
> also, DO get a gallon of roofing cement (tar
> asphalt) and paint the tower section from one foot below the top, MOUNDED
> surface to one foot ABOVE the top surface of this mounded concrete. DO pour
> enough to get the top of the concrete above the level of the ground - use a
> form tube set about 6" down into the ground and extending between 6" and 8"
> above the ground level. iow, get a 1 foot long piece of 3' diam concrete
> form tube used for sign or highway columns. In fact, I have formed a
> relationship with a couple of sign companies and have them do odd jobs like
> drilling the 3' diam hole and I have them do plate welding, winch/crane work,
> buy the cardboard concrete form tube. Remember, mound the top of the pour
> about 3 - 4" above the top edge of that form tube. Do NOT allow any chance
> of dirt to cover the top of that concrete foundation.
>
> some of the above is from about 4 yrs of being a sign inspector, more is
> plain old common sense. btw, about the asphalt, our swamp coolers at home
> never rusted out... most did within 2 yrs. tried pricing one of those
> lately?<G>
>
> good luck
> chas, k5dam
>
>
> Chas
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