[TowerTalk] TX-455 Engineering Drawings

[Jim Lux]

At 01:56 PM 1/8/2004 -0800, Jim Venneman wrote:
>Greetings,
>
>Many thanks to all of you who sent me comments last week concerning my 
>plot plan question. All were most helpful.
>
>I now have a new problem and not sure how to proceed. Our county's 
>Building Dept wants two wet-stamped copies of engineering drawings for the 
>TX-455 tower with my permit application. I have copies of old engineering 
>drawings that were used when the current owner of this tower erecetd it in 
>a neighboring county in 1995. Problem is - I am talking about an old U.S. 
>Towers TX-455 that was built around 1991-92. The TX-455 now has a 
>different design and the company engineer will not wet-stamp the old 
>drawings for me, saying that building code requirements have changed and 
>the old tower won't comply with existing wind load standards. I don't know 
>whether they are telling me the truth or whether they hope that I'll 
>purchase a new TX-455 instead.

The US Towers engineer may be speaking the truth. Standards have changed 
over the years. However, their advice is sound:

>  They did suggest I try contacting a local engineer for a possible 
> wet-stamp on the old drawings. I'm wondering why an engineer would do 
> this if the tower is out of compliance, as they say?

The generic tower as presented on the drawings may not comply with the 
general standards. Your specific installation (perhaps with a different 
base, or taking into account your specific soil conditions, or your 
specific installation location, or.or.or.) may be perfectly fine in your 
area.  For instance, the generic tower standards may require calculating 
for a given snow load.  You might never get that much snow in Auburn.

Maybe the engineer would do some calculations and determine that you can 
only put X square feet of antenna on the tower instead of the Y square feet 
the drawings specify, but, since you want to put less than X square feet 
up, you're in great shape.


>So - should I try sweet-talking the county into accepting my old drawings 
>along with a current wet-stamped copy of the updated base diagram or just 
>forget the whole thing and start saving my money for the new tower design?


Since you're going to presumably have to pay an engineer to sign and seal 
the base diagram, why not have them look at the tower drawings as well, and 
supply a supplemental analysis. Your local engineer will (should!) know 
what the folks in Placer county want.

Also, have you contemplated using Placer county's third party review 
system? http://www.placer.ca.gov/building/third-party-plan-rev.htm

It's tough to say whether you'd save any money by doing this though.  I've 
never been through this process, and I don't know what the target audience 
is. I suspect that it's not someone in your situation: a homeowner looking 
for permit for a small job.




>Thanks,
>
>Frustrated in Auburn, Ca.
>
>Jim  -WX6V-
>
>__________