[TowerTalk] Rebar Cage for Foundation

[Patrick Greenlee]

Yes, my rebar cage was made of weldable rebar and hot dipped galvanized 
as well.  Tashjian does good work.  If you check the Tashjian cage to 
tower interface you will see the most reasonable and practicable 
approach is welding.  Just off hand I can't think of an alternative that 
is as good.

Forgive my ignorance of US Tower designs as I have never studied their 
approach.

Patrick        NJ5G


On 5/4/2017 3:10 PM, Wes Stewart wrote:
> IMHO, the rebar in steel-reinforced-concrete is there to constrain the 
> concrete under tension.  It's not there to anchor the tower. Generally 
> speaking, welding isn't a good idea either, unless rebar graded for 
> weld-ability is used (Grade "W").  The stuff you buy at Home Depot is 
> probably Chinese made and of questionable quality.
>
> If the OP would simply download the instructions from US Tower, the 
> foundation is fully described. 
> http://www.ustower.com/wp-content/uploads/2014/05/TMM-433HD.pdf Three 
> anchor bolts go in the concrete and the rebar is placed at the sides 
> and corners of the foundation.  There is no connection between them 
> and a footnote specifically states: "No welding allowed."  Tie the 
> bars and be done with it.
>
> Wes  N7WS
>
>
> On 5/4/2017 11:22 AM, Patrick Greenlee wrote:
>> A rebar cage is not rocket surgery or brain science! To give you 
>> better advice you need to give some details on the tower to rebar 
>> cage connection.  There are several methods of connecting the 
>> concrete to the tower base. My Tashjian 70 foot crank-up/tilt-over 
>> has bar stock protruding vertically downward from all three legs of 
>> the tower. The bar stock is 3 inches wide and each of the 3 pieces of 
>> bar has 6 holes on 2 1/2 inch centers.  Similar steel bars with 
>> matching holes for 3/4 inch bolts are set in concrete and bolt to the 
>> tower.  The bars in the concrete are welded to the rebar cage.
>>
>> Having fairly recently become a "bionic man" (pacemaker 
>> defibrillator) I'm not supposed to weld so bought the cage built from 
>> Tashjian (excellent materials and workmanship) but if I had it to do 
>> over I would have hired a local welder to do the welding and I would 
>> have done the assembly in prep for that myself.  My foundation (as 
>> per Tashjian drawings) is 4'x4' square and 8 ft deep.  I formed up an 
>> 8x10 ft rectangle centered on the 4x4 hole using 2x6 lumber (5 1/2 
>> inches wide) to give me extra tilt resistance and a nice place to 
>> stand when doing anything at the tower base. I used significant 
>> quantities of rebar to tie the 8x10 slab to the 4x4 central core of 
>> the composite foundation.
>>
>> There are numerous other tower to foundation designs.  To offer 
>> additional assistance I think most of us here would need more info 
>> about your specific tower mating system to be able to give actionable 
>> advice.  I am happy to offer more assistance if you can supply more 
>> details and maybe someone else has some good ideas for you too.
>>
>> If you don't weld and have no access to a good welder then buy the 
>> cage pre-built.
>>
>> Patrick        NJ5G
>>
>>
>>
>> On 5/4/2017 11:37 AM, Joe Partlow wrote:
>>> I need to pour a base for a TMM-433HD tower but first I need a rebar 
>>> cage.
>>> Do it myself or hire someone and who would I hire?
>>>
>>
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