[TowerTalk] Achor bolts?

[jimlux]

On 3/24/18 5:21 PM, Steve Maki wrote:
> Yep, because closely spaced bolts can more easily pull out a *chunk* of 
> concrete containing all the bolts than widely spaced ones. I was 
> thinking of bolts *slipping* out of the concrete.
> 

I think that properly installed bolts in concrete, whether "cast in 
place" or chemical anchors held in by adhesive, fail by either the bolt 
pulling apart (metal failure) or the concrete pulling out.

If the bolt comes out of the hole, I think that's what's called a 
"workmanship" failure, as opposed to a design failure.







> -Steve K8LX
> 
> On 03/24/18 19:11 PM, Mike Fahmie via TowerTalk wrote:
> 
>> No, the pull out strength will depend on how far apart the anchors
>> are.  Closely spaced anchors will compromise pull out strength.
>> Optimum spacing will depend on anchor depth.-Mike WA6ZTY
>>
>> From: Steve Maki <lists at oakcom.org> To: towertalk
>> <towertalk at contesting.com> Sent: Saturday, March 24, 2018 4:07 PM 
>> Subject: Re: [TowerTalk] Achor bolts?
>>
>> How many bolts? Obviously 10 bolts will have 10x the strength of
>> one, including pull out strength.
>>
>> Most SS towers are designed for fewer large bolts rather than many
>> small bolts. Part of the reason for that is corrosion concern.
>>
>> Let the flange hole size be your guide! Of course, take a quick
>> glance at the manufacturer's foundation plans...
>>
>> -Steve K8LX
>>
>> On 03/24/18 9:34 AM, Hans Hammarquist via TowerTalk wrote:
>>
>>> Dear towertalkers,
>>>
>>> The are claims in a discussion on Face Book that an anchor bolt,
>>> "5/8 in. x 12 in. Hot-Galvanized", is suitable for a free standing
>>> tower. Someone even claims it is used for a 400' freestanding
>>> tower. It doesn't make sense to me but I might be overly
>>> pessimistic.
>>>
>>> I hate to start lengthy discussions and this might be one of them
>>> so, please, comment only if you have a well grounded answer. I'm
>>> sure there are plenty of opinions about it like my own, but I would
>>> like to know if my guts feeling is right or wrong. What I am afraid
>>> of is that you can pull out an anchor bolt like that right out of
>>> curred concrete.
>>>
>>> 73 de,
>>>
>>>
> 
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