[TowerTalk] BASE REBAR and Lightning

[Jim Lux]

kr7x at comcast.net wrote:
> List:
> 
> The "Building Code Requirements for Structural Concrete" ACI-318-05 section
> 7.7.1 - Cast-in-place concrete (nonprestressed)
> 
> states "The following minimum concrete cover shall be provided for reinforcement...
> 
> (a) Concrete cast against and permanently exposed to earth          3 in.
> (b) Concrete exposed to earth or weather:
> 
>             No. 6 through No. 18 Bars                                              2 in.
>             No. 5 bar, W31 or D31 Wire, and smaller                       1-1/2 in.
> 
>  .... continues .....
> 
> This code is used by all building codes in the US, the CBC (California Building Code) and the IBC.
> 
> The emphasis is .... the minimum cover shall be.....
> 
> The cover requirement is to prevent corrosion and subsequent spalling and failure due to constant exposure to moisture through the microcracks that occure in all concrete. This is a servicablility requirement not a stress design requirement. It becomes a design requirement by providing for durablility.
> 
> Regards
> Lonberg Design Group, Ltd.
> Hank Lonberg, P.E.,S.E.
> President
> 


Out of curiosity.. the cover requirement is on the reinforcing.  But, is 
the embedded tower section reinforcing, or something else.

   I'm thinking that there are lots of cases where something other than 
reinforcing protrudes within the soil/concrete area: plumbing 
penetrating the slab in a house, underground utility conduits coming up 
inside the footing, etc.  None of these are structural, though.  The 
tower section could be (or, maybe, it's only quasi structural...)