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RE: Pre-Eng Building Companies

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I usually have to make at least one call to the PEMB engineer in order
to dicipher their reaction summary.  Usually I end up speaking to the
tech who ran the design program since the engineer is rarely available.
Hopefully you are at least getting metal building plans that are signed
and sealed by the engineer. It doesn't sound like you are getting
complete reaction summaries.  Generally, unless you have some other
contractual arrangement, the foundation design and anchor rod embedment
configuration is the responsibility of the SER.  The building engineer
should spec the location, diameter, and material spec of the anchor
bolts and all loads that are transferred to your foundation through
these anchor bolts. This is the only sensible way to allocate design
responsibility and liability between the two parties in my opinion.


Christopher Banbury, PE
President
Ark Engineering, Inc.
PO Box 10129, Brooksville, FL 34603
22 N. Broad ST, Brooksville, FL 34601
Phone: (352) 754-2424
FAX: (352) 754-2412
www.arkengineering.net
 

-----Original Message-----
From: Gary L. Hodgson and Assoc. [mailto:ghodgson(--nospam--at)bellnet.ca] 
Sent: Tuesday, October 17, 2006 9:30 AM
To: SEAINT Mail List
Subject: Pre-Eng Building Companies

List,

I often design foundations for pre-engineered metal buildings and I
wondered if any of you have had similar problems with the way loads and
load combinations are given. I find that they are too vague. These
pre-eng building companies give the following data: dead load,
collateral load, lateral seismic load, longitudinal seismic load and
partial roof loads 1 thru 3 or 4. These are not too bad as you can
usually figure out what they are, with the exception of pattern loads. 
They usually don't say what the live load (as opposed to snow load) is -
you have to figure out that it is non-existent.

However, the real problem arises with wind loads and crane loads, e.g.,
lateral primary wind loads 1 thru 6 and longitudinal wind loads 1 thru
6.
They never say whether the wind is from left to right or vice-versa or
whether it contains internal suction or pressure. They leave it up to
the engineer to determine what they are and whether or not they are
applicable to the foundations. The same is true for crane loads,
particularly if there is more than one crane. Crane Load 1 thru x or
Crane Load Left (or right) 1 thru x without saying whether these contain
horizontal thrust or not.

I have dealt with as many as nine different PEMB companies and I think
Butler's are the best in that they actually give you individual loads,
i.e., wind left, wind right, internal suction, internal pressure, etc.,
and allow you to choose the proper load combinations. On the other hand,
I truly dislike Robertson Building Systems loadings as they give you all
of these different wind or crane combinations as described above without
telling you what they consist of. It would not require any changes to
their program to inform one what the combinations consist of, just put
the definitions in the preamble to the loadings.

Another beef is that the Robertson loads for preliminary design are
never in the same order as the final loads that are issued later.

I don't believe that there is any difference between PEMB companies in
the 2 countries as most the computer programs have originated in the US
and are used in both the US and Canada.

What is ironic about these loadings is that some of these PEMB
manufacturers put a note with their loadings that the foundations are
the sole responsibility of the foundation designer.

Cheers,
Gary


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