[TowerTalk] Calculations

[Alan C. Zack]

Having had just gone through this process I have the following comments:
I agree the $250.00 charge seems reasonable as the P.E. has to take 
the manufacturer's drawings and calculate the wind loads, etc, from 
them.  What I received was two sets of nine pages of very complicated 
calculations.  I have a E.E. degree and an I.E. degree but don't fully 
understand what is contained in the calcs.  They are based on the 
IBC-2000 Bldg code using UBC 1618 wind loads.  The first and last 
pages have the wet stamp by the P.E.  I had thought the Bldg Inspector 
might have kept them for awhile and looked them over before approving 
them but the first guy who I had been dealing with said they looked 
good, called over his supervisor who had previously explained to me 
what I needed, who also approved them.  They kept one of the two sets 
and gave me the other set with a stamp on each page showing approved 
for construction.  I have to have this set available for the field 
inspector when he comes out to see the hole and rebar before the 
concrete is poured and again for the final approval.
I would disagree on the cost of the shipping of the drawings.  It was 
included in the price of the calcs and were sent in one of those USPO 
Priority Mail flat rate envelopes for $3.25 that I received in about 
two days.
I agree that the P.E. should be paid a reasonable fee for his services 
but what is wrong with the tower manufacturer paying for it and 
getting the rights to be able to provide the drawings to customers 
when required?  There is a copyright notice on the drawings but it is 
held by the tower manufacturer, not the P.E., so it seems the drawings 
are the property of the manufacturer.

Jim Lux wrote:

> I'm sure you meant "recurring costs should be minimal"...
> 
> It depends on how the company getting the calculations contracted with the
> engineer.
> 
> Most building departments want a "wet-stamped" set of calculations, which
> implies that the engineer has reviewed the calculations for that specific
> installation and so forth.  This "individual review" would be both legally
> and ethically required. The engineer is responsible for also knowing the
> local peculiarities of the code, etc. Just to put $250 into perspective,
> that's probably around 2-3 hours of the engineer's time, plus all the
> incidental costs involved. (does the $250 include shipping the drawings, for
> instance.. that's $25 right there)
> 
> Indeed, the incremental cost for an engineer to "review" the calculations
> might be less than the first time, but bear in mind that's probably what the
> engineer is doing the first time.  That is, the $250 pays for the licensed
> engineer to review the calculations provided by the manufacturer. I'm not a
> tower designer, so if someone just brought me all the drawings for the
> tower, it would cost a lot more than $250 to do all the calculations from
> scratch.  You'd have to look up the material properties of the parts the mfr
> used, check the drawings for the kinds of welds and bolts, etc.  Someone who
> designs towers and similar structures for a living would have all this
> information at their fingertips, and would know at a glance if the mfr is
> using a "generally accepted industry practice" so the strutctural analysis
> they'd be reviewing would be fairly cookbook.A "skilled practitioner" would
> know where the trouble points might be and home in on those.
> 
> 
> All in all, $250 is very reasonable for this kind of professional review.
> 
> 
> ----- Original Message -----
> From: <WarrenWolff at aol.com>
> To: <towertalk at contesting.com>
> Sent: Sunday, September 12, 2004 12:58 AM
> Subject: [TowerTalk] Calculations
> 
> 
> 
>>And once a fellow gets a set of 90 MPH calculations for $250  or so, why,
> 
> o'
> 
>>why should any future sales of the same calculations cost the  next fellow
> 
> the
> 
>>same $250?  The non-recurring cost should be minimal;  right?
>>
>>Warren
>>W5KKW
>>_______________________________________________

-- 
__________________________________________________________________________ 

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
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