[TowerTalk] Concrete base - tower

[RCM]

> On Oct 13, 2017, at 13:38, RMorris <robrk at nidhog.net> wrote:
> 
> 
> 
> Sent from my iPad
> 
>> 
>> 
>> ##  pad + pier is a pita.   The dirt you put back in there..around the pier, that
>> sits on the concrete base is...free weight.  You can easily dispense with the
>> form..but then  you will use a helluva lot more concrete..which is OK per Trylon.
>> But the re-bar setup is different. 
>> 
>> ##  If ground is clay, or solid enough, so the sides of the hole   dont cave in, 
>> you dont require the megabuck, pita  wooden form.   Flip side is.... the wooden form
>> is very expensive to build.  It comes out a wash,  or close to it.    Cost of wooden form
>> vs cost of extra concrete. 
>> 
>> ##  If a wooden form is used, it has to be carefully constructed.  Concrete weighs aprx
>> 4000 lbs  per cubic yard....=  150 lbs per cubic foot.   There is a huge stress on the wooden form as is.
>> There is also a huge stress on the portion of the wooden form that encompasses the pad.  Thats from the
>> sheer vertical compression weight of the  concrete in the pier.   Get it wrong...and  form starts to come apart
>> when you have poured 80% of the concrete into the form.... u are in for a rude awakening. 
>> 
>> ##  Even if it all goes ok, the  wooden form has to be removed. 

Sorry, I fat fingered a reply, on the iPad.

Here’s how the big boys do piers…. Don’t need no wood.

https://www.sonotube.com/sonotubeconcreteforms.aspx <https://www.sonotube.com/sonotubeconcreteforms.aspx>

Got to watch a 350 foot Rohn SS go up…

24x 24 foot hole, 40 yards of concrete. Pad and pier.

Each leg of the first section was 1100 pounds.