[TowerTalk] Welding Rebar

Sun Apr 13 14:37:40 EDT 2014

On 4/13/2014 1:56 PM, Gary Schafer wrote:
> Roger,

"My thoughts" which I'm afraid will be a bit wordy! <:-))

J-Bolts, or the properly sized and threaded rod for the largest future 
tower that could be installed "should work" IF that configuration meets 
the future tower's specs including the number and placement of the rods.

You might find the half inch plate to be a bit on the light side.
I think you will find that welding the ends of the ears to the plate Vs 
welding the length to the rod may require some adjustments in size and 
welding approach. You can't just stand the ears on the plate and weld.  
The entire contact area has to be welded which requires tapering the end 
of the ears so the weld starts at the center and is layered out to the 
edge. The finished appearance should "look like" the ear were stuck on 
the plate and a neat weld were made around the periphery. A certified 
welder would have no problem layering it up to the desired, final 
appearance (with no voids), but an engineer has to tell him what area of 
weld and what it's welded to is acceptable.

This is the highest stressed area for the entire tower installation. Get 
a qualified engineer to go over the base to make sure it's strong enough 
for present and future plans.

Modifying the base is no simple task. "It should be OK if it matches 
future and present designs for the same or larger towers

It's not me, but were it me, I'd find a competent engineer to go over 
the plans and welding needed/acceptable as well as all other fasteners.

It sounds like a good approach, but I'm not an engineer.

Good luck.

73,

Roger (K8RI)

>
> I have one of those towers to put up one day too. I was thinking rather than
> weld the ears to the large rod as the factory shows, using threaded rods
> coming out of the concrete and using a 1/2 inch plate to bolt the rods to.
> Then welding the ears on the plate that then bolt to the tower.
> That way I could easily use the foundation for a different tower if I wanted
> to change to something else.
>
> The threaded rods also make for easy leveling of the tower.
>
> What is your opinion of that?
>
> Thanks
> Gary  K4FMX
>
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
>> Roger (K8RI) on TT
>> Sent: Sunday, April 13, 2014 2:46 AM
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Welding Rebar
>>
>> On 4/13/2014 1:47 AM, Brian Amos wrote:
>>> If you weld it the rod may rust which will cause the concrete to
>> burst.
>>
>> Rusting requires an oxidation source.  Rod protruding from the concrete,
>> or flux.  I'm using Metal, Inert Gas or MIG for short. I'd not want to
>> use stick welding. These are "tack welds, not true welds. They are just
>> enough with what wiring I can do with one hand, that I'm not worried
>> about the cage changing shape before we pour the concrete.  The "twist"
>> is much like we use on aircraft nuts and bolts, except we are using soft
>> iron and not #20 or 24 SS.
>> I'm used to sticking the two ends into a tool, pulling a handle that
>> reminds me of a Ty-Wrap tool.  Just about instant twist.
>>
>> The Iron wire is large enough , #14 I think, that it can be twisted with
>> regular pliers.
>>
>> Tack welds are small enough that I'm not worried about changes in
>> strength.
>>
>> There are 3 major welds. Those are ones holding the 1/2" X 3" X 25" ears
>> to the #10 rerod  The tower and raising fixture bolted directly to
>> these.
>>
>> If we could get the rerod to stay in place we wouldn't need to fasten
>> it.  The rod just serves as a reinforcement for the concrete, although
>> with the LM470 the big stuff that holds the tower is part of the cage.
>>
>> I like the idea of everything connected as it serves as a very good UFER
>> ground. Course that connects to a network of over 600 feet of bare #2
>> that is cad welded to 32 or 33 8' ground rods.
>>
>> Speaking of grounds. I've lost 2 of the big Diamond dual band (144/440)
>> antennas. I think I've lost a system ground in the shop and it went to
>> ground through the antenna.
>>
>> 73
>>
>> Roger (K8RI)
>>
>>
>>>    Not
>>> a fun situation as usually the recommended repair is completely remove
>> the
>>> foundation and replace it. As a foundation engineer I only hear the
>>> failures and what the standard of practice and code say, so maybe it
>> has
>>> worked under the right circumstances. If it has an issue and it was
>> not
>>> built to code the insurance company will not cover you.
>>>
>>> Tying rebar is not fun and can be hard work but stout teenage boys
>> will
>>> learn quickly and work for a small portion of what a concrete company
>> would
>>> charge. I usually offer a favorite meal ajdand tgat is ebough.  You
>> may
>>> even find some free and experienced help from your ham club. I know
>>> whenever someone in my club needs help with something that falls
>> within my
>>> line of work I am more than willing to lend a hand.
>>>
>>> Brian
>>> KF7OVD
>>> On Apr 12, 2014 10:42 PM, "Edwin Karl" <edk0kl at centurytel.net> wrote:
>>>
>>>> Roger,
>>>>
>>>> As part of my mis-spent youth I was an iron worker, worked at it for
>> about
>>>> 6 years.
>>>> We were referred to as "rod busters" by some. In any event installed
>> lots
>>>> of iron
>>>> in the new York area.
>>>>
>>>> Now that I'm retired, I built my own home, not with my hands, but was
>> the
>>>> general
>>>> contractor. You can do that in the country ... I did do the
>> reinforcing
>>>> myself; so my
>>>> driveway, sidewalks, patio, basement walls and floor all have steel
>>>> internally. The
>>>> also barn has a reinforced concrete floor.
>>>>
>>>> The tower is an AN Wireless  90 footer with a big foundation, rear 3
>>>> layers, top bottom
>>>> and middle is about 12 feet deep, took 21 yards of concrete to fill
>> the
>>>> hole. There is a
>>>> section of tower made to go in the foundation which splices to the
>> rear.
>>>> Now I'm saying all this because of a decision I made years ago, if I
>> had
>>>> the chance, this is
>>>> how I would choose to build my own home, etc. It might be nit picking
>> but
>>>> the issue with me
>>>> probably pertains more to structural iron, like the tower etc. Don't
>> do
>>>> anything like welding
>>>> which may change the characteristics of the iron negatively. Also
>> affects
>>>> galvanizing etc.
>>>> Probably way over thinking the issue, which I usually do.
>>>>
>>>> I also will confess in my day, except where cad welding 1 1/4 rear
>> for
>>>> power houses etc,
>>>> never saw rear welded. Generally a splice is 20 times the diameter
>> side by
>>>> side and double
>>>> tied.Compared to structural, rear is soft, we would bend it on site
>> for
>>>> hooks and angles, so I
>>>> suspect it's already not too stuff. But as I said initially the bar
>>>> reinforces the concrete, which
>>>> holds the bar in place.
>>>>
>>>> Sorry for being so lengthy ... but, if there are other issues as you
>>>> mention than explain why welding
>>>> might be acceptable. We would take columns and beams using wire to
>> kind of
>>>> guy it internally,  if
>>>> the item has a long way to go or was a difficult pick for the crane
>> etc.
>>>> If you are having the job
>>>> fabricated off site it probably could be done either way, if you're
>> alone
>>>> tack welding could work.
>>>>
>>>> I wish you well, and would appreciate hearing from you as the project
>>>> progresses.
>>>>
>>>> By the way, 8 or 9 inch lineman's pliers and end cutting nippers are
>> tools
>>>> of the trade, The nippers
>>>> work real well when tightening the connection, After a few mistakes,
>> you
>>>> can get the hang of it.
>>>>
>>>> Very 73!
>>>>
>>>> ed K0KL
>>>>
>>>>
>>>>
>>>> On 4/12/2014 9:37 PM, Roger (K8RI) on TT wrote:
>>>>
>>>>> On 1/5/2014 12:58 AM, Roger (K8RI) on TT wrote:
>>>>>
>>>>>> On 1/4/2014 4:01 PM, Ed K0KL wrote:
>>>>>>
>>>>>>> I can't stand it any longer ...
>>>>>>>
>>>>> And the problem is?
>>>>>
>>>>> If wired in place or near the hole they work fine. If shipped, or
>> handled
>>>>> a lot they seem to come already welded.
>>>>>
>>>>> As I only have one useful hand, tack welding is faster, easier, and
>> makes
>>>>> for a far more secure joint than wiring one with just one hand.
>>>>>
>>>>> I noted when at my steel supplier, they had a cage, mostly done that
>> was
>>>>> all welded.  The customer would put it on a trailer, haul it 10
>> miles or so
>>>>> and then stick it in the hole with the same dimensions as when he
>> picked it
>>>>> up.
>>>>>
>>>>> 73
>>>>>
>>>>> Roger (K8RI)
>>>>>
>>>>>
>>>>>
>>>>>>> Wire ties are fine to keep the rebar touching from bar to band
>> (the
>>>>>>> smaller rod surrounding the
>>>>>>> verticals or horizontals as it were). It has been used for years
>> on
>>>>>>> buildings, roadways, etc. Generally
>>>>>>> speaking the concrete holds the connection together, the
>> connection and
>>>>>>> rod make the concrete
>>>>>>> strong ...
>>>>>>>
>>>>>>>
>>>>>> Order towers with the rebar cage and they likely will come welded
>> and
>>>>>> not tied.
>>>>>> That's been the local experience.
>>>>>>
>>>>>> 73
>>>>>>
>>>>>> Roger (K8RI)
>>>>>>
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
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