[TowerTalk] Concrete anchor

[Rich Hallman - N7TR]

I'm also in the middle of deciding on using an existing foundation or pouring a new one.    What thickness plate would you go with for something like an hdx589?  Buying the plate and having it drilled for the old foundation bolts.....then drilling holes for the new base bolts seems like a far easier option.   Of course using structural bolts for the new base.  1 1/8 diameter f1445 grade 55 is what I'm looking at for the 589.

Thoughts?

Rich Hallman N7TR


On Aug 14, 2015, at 9:06 AM, K7LXC--- via TowerTalk <towertalk at contesting.com> wrote:

>> I have a 165ft rotating tower going up next Spring so will  not be
> putting a larger tower on this base, but it does sound like I need to get  a fab 
> shop to just go ahead and build me the base. No galvanizers locally so  
> paint will have to do.  
> 
>> I have a concrete base next to my shop  that once had 89ft US Crankup
> Tower
>> on it. The tower is gone, and I  acquired a 55ft US Tower that I want to
> bolt
>> to this base for use in my  shop. The bolts that once held the bigger
> tower
>> is still there, but I  plan to cut them off and install chemical anchors
> to
>> support the smaller  bolt pattern. The other option was to fabricate an
>> adapter plate that  would mate the 55ft tower T-base to the bigger bolt
>> pattern, but this  sounds like much more work than simply drilling into
> the
>> concrete and  installing new anchors.
>> 
>> I never used chemical anchors for this  purpose and would appreciate any
>> suggestions on size, and where I can  source them. The rebar pattern for
> the
>> bigger tower is much wider than  the bolt pattern for the smaller tower,
> so I
>> there is little chance for  me to hit rebar when I drill. (I suspect I
> will
>> need a BIG  drill).
> 
>    I assume that the big tower is a Rohn of some ilk.  Adapting the base 
> for the new tower is pretty simple - and you don't need  anything fabricated.
> 
>    There are a couple of tower base options: 1) flat  plate for regular 
> bottom section and 2) pier pin. For 1) you can put the  plate on the base and 
> use a rotary hammer with concrete coring bit to drill  out the bolt holes. 
> I'm not sure what you mean by a chemical anchor but in this  case you'd use 
> some industrial epoxy to anchor the bolts to the concrete. The  same with the 
> pier pin. 
> 
>    Either option works although different folks prefer  one over the 
> other. 
> 
> Cheers & GL,
> Steve     K7LXC
> TOWER TECH 
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