[TowerTalk] Calculations

[Alan C. Zack]

Hank,
In regards to my comments on the subject, I have never mentioned a 
problem with the fees involved in obtaining the calcs, my only problem 
is why some manufacturers can provide them and others cannot, 
especially since, as you pointed out, they are are based on the root 
TIA/EIA-222-F specifications.  It would seem any tower manufacturer, 
especially a major one, would have a P.E. on call to provide these 
calcs when required for an appropriate fee.
As far as dealing with the Bldg Inspector, when they have a 
requirement to fill they want to see that requirement in front of 
them.  At my City Hall there is always a line of contractors with 
drawings to be approved and the inspector just doesn't want to convert 
one set of specs to another in order to meet their requirements.  I 
submitted great drawings from UST based on UBC-97 but was told just 
come back and submit the same info based on IBC-2000 and I'd get my 
permit.  UST came back and said none of their crank ups could comply 
to IBC-2000.  If all they had to do is to incorporate the 
TIA/EIA-222-F specifications into a drawing showing they complied with 
IBC-2000 why couldn't they do it?
I am not putting down your opinions or having to pay for getting the 
specs, just that it is hard to understand why some manufacturers can 
easily provide them and others cannot.  Yes, it might just be that 
they did not want to bother with it but someday more and more Bldg 
Depts may require different specs than their basic UBC-97 drawings.
I have been partaking on the free BBQ at UST during the Intl DX 
Convention for the last 20 years or so, and on making my move from a 
CC&R controlled area to one where I could have a tower I contacted UST 
first for my order.  I was very disappointed that after 3 months of 
phone calls and emails I was told their outside P.E. could not provide 
IBC-2000 wind calcs for any of their crank ups.

kr7x at comcast.net wrote:

> To the list:
> The IBC, both 2000 and 2003, and the UBC all refer to the TIA/EIA-222-F specification when they discuss the wind load and analysis of towers. The actual design criteria for towers can be considered the same for all three codes. Actually the IBC 2003 is the latest version of the IBC 2000. The only variables that change from location to location for all the codes is the design wind velocity and the site soils.
> The TIA/EIA design wind velocities as well as the UBC's are based on the "fastest mile" wind speed; while the IBC (2000 & 2003) as well as the ASCE 7-02 are based on the "fastest 3-second" gust. In the IBC's there is a table that relates the two wind velocity concepts, fastest mile vs 3-second gust, together.
> The site soils in all the codes are handled by 5 basic types with extremely conservative allowable strength values.
> So in essence there is only 1-design standard and it doesn't matter which code, UBC or IBC. The real focus is to educate the building offical that this is the case. A licensed structural engineer in the particular jurisdiction has more credibility in this regard than either the permit applicant or the manufacturer.
> In a general comment to all on the list regarding the discussion of the cost of engineering.
>  I feel that it is demeaning to the profession and to me personally. What you are actually paying for is the accumulated knowledge and understanding of all the physics involved in the wind or seismic design of the tower as a structural system.
> If you don't like the fee, my suggestion is to spend 4+ years in accreditied university coursework with passing marks; take the 8-hr EIT test and pass; spend 4 years under the guidance of an licensed engineer(s); take the 16-hr structural licensing examination and pass,  in the state of your choice and then "DO IT YOURSELF".
> Regards
> Lonberg Design Group, Ltd.
> Hank Lonberg, P.E.,S.E. / KR7X
> President
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 

-- 
__________________________________________________________________________ 

Alan Zack
Amateur Radio Station K7ACZ
Las Vegas, Nevada, USA
Quality Engineer, The Boeing Company, Retired
Aviation Chief Warrant Officer, U.S. Coast Guard, Retired
U.S. Coast Guard, Always Ready, Always There
Every hour, Every day, Around the Clock and Around the World
SEMPER PARATUS
http://gocoastguard.com