[TowerTalk] Dimensions of a tower concrete base

[Hank Lonberg]

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
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk 

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