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RE: Table 16-O - Horizontal Force Factors, ap and Rp

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I believe if its period is greater than 0.7 seconds it is considered
flexible. I doubt that any rooftop mechanical unit would be considered
flexible unless it was very tall and narrow.

Gerard Madden, P.E.
Civil Engineer, Associate
CRJ Associates, Inc.
email: gerardm(--nospam--at)crjarch.com
tel: 650.324.0691
fax: 650.324.0927
web: www.crjarch.com


> -----Original Message-----
> From:	From the desk of Joe Otto [SMTP:jmo_engineering(--nospam--at)email.msn.com]
> Sent:	Thursday, August 26, 1999 5:20 PM
> To:	seaint(--nospam--at)seaint.org
> Subject:	RE: Table 16-O - Horizontal Force Factors, ap and Rp
> 
> How can you prove that a A/C unit is not flexible?
> 
> Joseph M. Otto
> Ireland Engineering
> Fremont, CA
> 
> -----Original Message-----
> From: Gerard Madden [mailto:GerardM(--nospam--at)crjarch.com]
> Sent: Thursday, August 26, 1999 2:13 PM
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: Table 16-O - Horizontal Force Factors, ap and Rp
> 
> 
> There was an erratta published where note c was corrected to read:
> 
> "Any FLEXIBLE equipment laterally braced or anchored to the structural
> frame at a point below their center of mass"
> 
> So if your unit is not flexible, there is no need to use the 2.5
> value.
> 
> Gerard Madden, P.E.
> Civil Engineer, Associate
> CRJ Associates, Inc.
> email: gerardm(--nospam--at)crjarch.com
> tel: 650.324.0691
> fax: 650.324.0927
> web: www.crjarch.com
> 
> 
> > -----Original Message-----
> > From:	From the desk of Joe Otto
> [SMTP:jmo_engineering(--nospam--at)email.msn.com]
> > Sent:	Thursday, August 26, 1999 2:02 PM
> > To:	Seaint@Seaint. Org
> > Subject:	Table 16-O - Horizontal Force Factors, ap and Rp
> >
> > On one of our jobs, we're installing some air conditioning package
> > units on
> > top of a typical panelized roof.
> >
> > We used a value of 1.0 for ap as required by 3.B in Table 16-O (page
> > 2-33).
> >
> > We received a plan check comment indicating that the value of ap
> > should be
> > 2.5 because the attachment of the unit is below its center of mass
> as
> > is
> > required by 3C.  If I use the 2.5 value, I get a value which is
> > greater than
> > that required for emergency power systems (3.D) and containers with
> > flammable hazardous materials (3.E).
> >
> > Both parts of the code appear to apply?  Can anyone clarify when 1.0
> > or 2.5
> > are truly intended to be used.
> >
> > Thanks in advance.
> >
> > Joseph M. Otto, PE
> > Ireland Engineering
> > Fremont, CA
> >
> >
> >
> >
> 
> 
> 
> 
>