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Re[4]: MBMA Code and Wind Loads

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     UBC's wind load is the "simplified" version of the ASCE 7, applicable
     only to simple structures. You will find this information in the
     commentaries of the UBC documentation. For more complicated
     structures, and where jurisdictions dictate, ASCE 7-xx shall be used.
     For more complex structures, wind tunnel testing "is" required.

     Finally, I have to my knowledge, MBMA "is not" a code. If you read
     their manual, they assert so themselves. Their manual is intended for
     use by their subscribed building design companies as a guide. We all
     have taken advantage of their input (information) to design all kinds
     of building structures, but never without application of engineering
     judgment.

     As for the engineer doubting the building reactions, I respect his
     judgment. However, there are many aspects here that, in my opinion, go
     beyond codes of any kind. Most importantly, if the reactions are
     obtained (and supplied) by a standard which was acceptable to the
     contract documents then there should be no problems designing
     foundation for the given loads...it is the contract (unless they are
     dangerously miscalculated). If the scope of his work is to investigate
     adequacy of the provided data, then, may be questions can be raised,
     but with due regards to the building types. It is believed that metal
     buildings in general provide certain damping effect against wind (due
     to their flexibility), and that might be the reason why loads are
     smaller that if ASCE 7 is used.

     Just my 2 cents worth.

     Ghassem Khosrownia.


______________________________ Reply Separator _________________________________
Subject: Re[3]: MBMA Code and Wind Loads
Author:  Ed.Haninger(--nospam--at)fluordaniel.com at Internet
Date:    2/18/98 1:47 AM


     For metal buildings I specify that the UBC be used for design.  The 94
     UBC is currently used for most building departments.  I don't have to
     worry about MBMA and the building department accepts it.  The 94 UBC
     is still the old "fastest mile" procedure, but it gives generally
     lower, but reasonable loads compared with the ASCE 7-95.

     Ed Haninger
     Fluor Daniel
     in "rainy" California


______________________________ Reply Separator
_________________________________
Subject: Re[2]: MBMA Code and Wind Loads
Author:  James_F_Fulton@rohmhaas.com_at_-FDInternet at FDINET
Date:    02/16/1998 4:07 PM


I would tend to agree that the source of wind load provisions in ASCE 7-95
is
not MBMA.  About 3 years ago I compared the wind loads on a metal building
design determined using MBMA and ASCE 7 (either 93 or 88, doesn't matter
here). The MBMA loads were much less.  MBMB has some justification for this,

but I am not sure what it is. Since wind loads for low rise buildings from
ASCE 7-95 end up being not largely different from those determined from ASCE

7-93, I suspect that MBMA wind loads are still much less than the
corresponding ASCE 7-95 values. In the process of this work, I was
developing
a metal bldg. spec, and I specified that the building was to be designed to
1993 BOCA Code, particularly in regards to wind loads.

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