Based on this (good) information, it seems to me that a manufacturer
could have an engineer make up a series of charts or tables showing the
surviving loads in each soil type at increasing wind speeds and icing
conditions sufficient to encompass nearly any code requirement. Have
these stamped, and provided to each purchaser, and pay the engineer an
ongoing fee quarterly for each set sent out. The building official could
look up his or her favorite wind speed on the chart or table and approve
the installation based on that information.
The only problem I could see would be if the official requires a stamp
from a local engineer. In this case, perhaps some amateur association,
like ARRL, should request that amateurs who are licensed volunteer from
each state to provide a review and stamp service at a reduced fee, since
many of the tower requests reviewed would be redundant, so it wouldn't be
like performing a new engineering study each time from scratch. For most
towers, the engineer could just pull a file on that model and verify that
his file numbers agree with the ones being submitted for the permit.
I would think that these practices could help manufacturers sell more
towers to wary amateurs, and that they would also help us get more people
on the air to help perpetuate the amateur service.
- Just an idea.
On Tue, 14 Sep 2004 18:25:47 +0000 kr7x@comcast.net writes:
> 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
> t
> _______________________________________________
>
> 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@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
________________________________________________________________
Get your name as your email address.
Includes spam protection, 1GB storage, no ads and more
Only $1.99/ month - visit http://www.mysite.com/name today!
_______________________________________________
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@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|