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RE: storage racks with partially restrained moment connections - wind frame analysis in high seismic zones

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I still think it would hurt if a pallet full of TV's was launched off the
top shelf of a 16 foot tall storage rack onto my head. It has been a while
since I had physics but I have a pretty good gut feeling for this one.  I
see the potential for people being masscred by flying consumer goods whether
the racks are designed according to the code or not.

It seems that putting specifically worded requirements for the method of
fundamental period determination, maximum fundamental period, drift limits,
ect... would be a good idea for wholesale retail warehouses.  Maybe these
issues are already addressed in the 97 RMI, they weren't in the 97 UBC. 

On calculations submitted to building departments,  I do not have twenty
years of experience but I have reviewed dozens of rack permits.  I feel
safer with some of the designs than others, but 97 UBC 2224.3 requires
flexural torsional buckling to be checked for column design and I do not
think there was one permit where calculations checking flexural torsional
buckling were submitted without teeth being pulled out.   

Scott M Haan  P.E.
Plan Review Engineer
Building Safety Division http://muni.org/building, 
Development Services Department,
Municipality of Anchorage
phone: 907-343-8183   fax: 907-249-7399
mailto:haansm(--nospam--at)ci.anchorage.ak.us

> -----Original Message-----
> From:	Sid Danandeh [SMTP:sdanandeh(--nospam--at)cityofpalmdale.org]
> Sent:	Monday, March 19, 2001 9:10 AM
> To:	'seaint(--nospam--at)seaint.org'
> Subject:	RE: storage racks with partially restrained moment
> connections -  wind frame analysis in high seismic zones
> 
> well 
> 
> In Southern California where I have worked for the past 20 years! Racks
> are
> plan checked and also inspected by the building depts.
> 
> Code allows the building official certain latitude if racks are less than
> 8
> feet tall. But if racks are taller than 8 feet most cities that I have
> worked for required structural engineering calculations.
> 
> There are couple of companies in Southern Ca that mostly perform rack
> designs one is called SEISMIC and its director Mr. Sal. He is very active
> in
> various committees. There are other rack design firms in Glendale etc.
> 
> The racks have their own base shear formula in the 1998 CA code. The rack
> foundation is also analyzed using beams on elastic foundation, or a
> simplified method by Eugene Birnbaum is very poplar to deign footing for
> racks. This method was accepted by LA County in 1986.
> 
> You are right Fire dept.'s also inspect racks . But they are interested in
> the so called  IN Rack sprinklers and high piled storage provisions. For
> the
> definition if the rack is more than 12 feet high its classified as high
> plied storage. High piled storage requirements kick in certain fire safety
> requirements for the building.
> 
> We have been basically using the SEAOC's blue book that was used a as the
> back bone for UBC's structural provisions for years and years. We were to
> use some more NEHERP provisions this year using the 2000 IBC , but IBC was
> not adopted in California. The UBC and the SEAOC blue book are very clear
> on
> their requirements for  design and inspection of racks and most major
> metropolitan cities in Southern California that I know of adhere to these
> requirements.
> 
> -----Original Message-----
> From: Sprague, Harold O. [mailto:SpragueHO(--nospam--at)bv.com]
> Sent: Saturday, March 17, 2001 10:43 AM
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: storage racks with partially restrained moment connections
> - wind frame analysis in high seismic zones
> 
> 
> As a member of the BSSC TS 13, storage racks fall in my chapter of the
> NEHRP.  This area has been a cause of concern and study.  But even more
> fundamental to structural theory is how racks are used and approved.
> Anyone
> can take a rack originally designed and built for Dallas and assemble it
> in
> the San Francisco area.  The inspection is a crap shoot.  If anything, the
> fire marshal might inspect it to see if the racks are loaded within the
> posted rating.  But whether or not the rack is in the appropriate Seismic
> Design Category is neither generally posted nor generally checked.
> 
> This is an area that requires further study and work by the RMI and TS 13.
> 
> Regards,
> Harold O. Sprague
> 
> 
> 
>