[TowerTalk] Tower Legs in Concrete

[K8RI on TT]

On 7/6/2011 1:22 PM, Eddy Swynar wrote:
> Hi Again Roger,
>
> On second reading of your note, what you say makes sense to me now---but in order to benefit from such a scenario, one would have to bury in concrete a complete 8' tower section...and since the sections are tapered, one would lose that much height in doing so.

That approach is so common it's what I thought of when you said "base 
extensions".  To me a base extension is ... well an extension of the 
tower base which most often is a short (5' or there abouts)  section of 
tower.

Now days I'd no longer bury the base in concrete, but use the "Pier Pin 
Base" for larger, guyed towers.  I've gone back to using "dirt bases" 
for small, guyed towers with relatively small antenna systems which work 
well in our soil.  The success of dirt bases and how much tower they 
will handle is highly dependent on soil conditions as well as the 
"Freeze/Thaw" cycle

73

Roger (K8RI)
> ~73~ de Eddy VE3CUI - VE3XZ
>
>
> **********************************************************************************************************************
>
>
> On 2011-07-06, at 11:13 AM, Eddy Swynar wrote:
>
>> Hi Roger,
>>
>> Read the line you just saved again---there are no cross braces at the base extensions...!    :>)
>>
>> ~73~ de Eddy VE3CUI - VE3XZ
>>
>>
>> **************************************************************************************************************
>>
>>
>> On 2011-07-06, at 8:50 AM, K8RI on TT wrote:
>>
>>> On 7/6/2011 7:16 AM, Eddy Swynar wrote:
>>>> Hi Chas,
>>>>
>>>> The Delhi-brand tower sections---including the base extensions that are placed inside the concrete base---have bolt holes at each end for attaching to the next section(s)...the extensions are essentially the "legs" of the tower sections minus the cross-braces.
>>> I would think the cross braces between the legs would be far more
>>> efficient making the bolts redundant
>>>
>>> 73
>>>
>>> Roger (K8RI)
>>>> The manufacturer recommends inserting long bolts through the bottom holes of each extension (again, the parts that are imbedded within concrete) to ensure (I guess) a firmer "bond" within the concrete after it has set, afforded by the fact that these bolts protrude 90-degrees from the plane of each extension...
>>>>
>>>> Sorta like the barb on the business end of a fish hook...
>>>>
>>>> ~73~ de Eddy VE3CUI - VE3XZ
>>>>
>>>>
>>>> ************************************************************************************************************************
>>>>
>>>>
>>>> On 2011-07-05, at 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.  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
>>>>> -- 
>>>>> A: Because it messes up the order in which people normally read text.<B>
>>>>> Q: Why is top-posting such a bad thing?<B>
>>>>> A: Top-posting.<b>
>>>>> Q: What is the most annoying thing in e-mail?<B>
>>>>>
>>>>> .
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