[TowerTalk] Dimensions of a tower concrete base

Al Williams alwilliams at olywa.net
Tue Sep 2 11:18:03 EDT 2008


Please explain the difference between "lateral force" and "the moment 
inherent in this type of structure"
and how they effect on tahe strength of the foundation.

k7puc


----- Original Message ----- 
From: "Hank Lonberg" <kr7x1 at verizon.net>
To: "'Bert Almemo'" <balmemo at sympatico.ca>; <towertalk at contesting.com>
Sent: Monday, September 01, 2008 9:14 PM
Subject: Re: [TowerTalk] Dimensions of a tower concrete base


> Bert:
>
> The best answer to your generalized questions is; it depends.
>
> Depends if the foundation is supporting only vertical load as
> in a guyed structure.
> Depends if the foundation is to support a cantilevered or free
> standing structure with both lateral force, vertical force and
> the moment inherent in this type of structure.
> Depends if the designer is trying to utilize a spread footing
> type of foundation.
> Depends if the designer is trying to utilize a post type of
> foundation.
> Depends heavily on the soil's characteristics and strength
> that you are trying to utilize.
>
> So you see, your question does not have a closed form of
> solution, but depends on what you are trying to accomplish and
> what type of loading the structure you are trying to support
> will impart to the foundation.
>
> A case can be made for either the shallow spread footing type
> of foundation or the smaller footprint deeper foundation. The
> trick is to size them adequately for the loading condition
> versus the soil conditions expected.
>
> Gut level, the amount of concrete for either design is most
> likely similar.
>
> Regards
> Lonberg Design Group, Ltd.
> H.S. Lonberg, P.E.,S.E.
> President
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of Bert
> Almemo
> Sent: Monday, September 01, 2008 8:51 PM
> To: 'Bob Maser'; towertalk at contesting.com
> Subject: Re: [TowerTalk] Dimensions of a tower concrete base
>
> Hi Bob,
>
> Thanks for your reply. Yes, I think you missed the point.
> Sorry! I'm talking
> about the concept in principle not if the total weight is
> exactly the same.
> According to the experts, the weight of the base has very
> little to do with
> the support of the structure. The weight only makes up for
> about 10% of the
> forces needed to support a given structure. 90% or so comes
> from the
> soil/dirt/sand enclosing the base. I'm not an expert in
> structural
> engineering and can't probably explain this properly.
>
> Anyway, back to my question - in principle is there a
> difference in
> force/strength to support a structure if the base is deeeper
> or shallower
> having basically the same weight and volume?
>
> 73 Bert, VE3OBU
>
>
>
>
>
> -----Original Message-----
> From: Bob Maser [mailto:bmaser at tampabay.rr.com]
> Sent: Monday, September 01, 2008 8:49 PM
> To: Bert Almemo
> Subject: Re: [TowerTalk] Dimensions of a tower concrete base
>
> The last time I looked, 3x3x6=54 and 4x4x4=64 so 64 will weigh
> more than 54
> will.  Am I missing something?
>
> Bob W6TR
> ----- Original Message -----
> From: "Bert Almemo" <balmemo at sympatico.ca>
> To: <towertalk at contesting.com>
> Sent: Monday, September 01, 2008 2:35 PM
> Subject: [TowerTalk] Dimensions of a tower concrete base
>
>
>> In general, is it better to go deep than wide when digging
> for a tower
>> base,
>> i.e. does a deeper base give better support than a shallower
> one with
>> basically the same volume? Is 3x3x6 better than 4x4x4 with
> everything else
>> being equal. Thanks.
>>
>> 73 Bert, VE3OBU
>>
>>
>> _______________________________________________
>>
>>
>>
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