[TowerTalk] [Bulk] Re: FW: Concrete Pad for U.S. Tower TX-472

[Grant Saviers]

With a significant amount of water in the hole after pumping the water 
out, it's better to pump the concrete into the bottom so the water will 
rise up on top.  Don't drop from a chute into standing water.  "a few 
inches" in a 4'x4' hole seems to me "significant" - 5+ ft^3 or 35+ gallons.

Another factor that an inspector might consider is the maximum free fall 
from a chute.
see 
http://www.ascconline.org/Portals/0/docs/POSITION-STATEMENTS/PS-17_FreeFallConcrete.pdf

Grant KZ1W

On 7/26/2015 13:09 PM, ve4xt at mymts.net wrote:
> I hope to pour in August, but I too have water. If it's only a few inches, is it worth worrying about?
>
> 73, Kelly
> ve4xt
>
> Sent from my iPhone
>
>> On Jul 26, 2015, at 13:31, "Patrick Greenlee" <patrick_g at windstream.net> wrote:
>>
>> My next tower install is coming late this summer or early fall (depending on when the tower is built/shipped.  I fully expect the hole 4x4x8 ft to at least partially fill up from ground water if I don't take precautions.  Even during the recent record setting drought I had ground water within 5 ft of the surface but this is NOT a drought year.
>>
>> Boat launching ramps are poured into forms fully submerged as concrete easily displaces the water without being "watered down." My concern is that the walls of the hole, if significantly soaked, may collapse. So I may put a sump pump in the hole with a float switch to keep the water pumped down to a couple inches.  I'll build a little cubical wood frame and cover it with geotextile to filter out solids and not let the pump clog.
>>
>> Patrick     NJ5G
>>
>>> On 7/25/2015 11:14 PM, Roger (K8RI) on TT wrote:
>>> I had no problem keeping it wet.  The spring water table was just a couple inches below the surface. We kept a sump pump running until the concrete was being poured into the hole.   It was a good dry mix relatively speaking, yet when the concrete reached the top, it was pushing out water.
>>>
>>> As I was breaking up the over flow a couple weeks later, someone asked, "Wouldn't it be easier to just paint it green?"  The dirt under the hardened overflow was still soggy.  So other than sprinkling the surface, keeping it wet was not a problem<:-)
>>>
>>> 73
>>>
>>> Roger (K8RI)
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