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

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You are correct, it is 0.06 seconds. I forgot the extra zero and I
remembered the wrong digit.
Nice Catch. 

Anyway, I haven't even tried to prove a what a roof top unit's period
is, but I would think that the manufacturer should start including that
information in their "cut sheets". Otherwise, the anchorage requirements
are now either going to be much heavier that before & or a quite of bit
of analysis is in order to figure out the period. I think any detailed
analysis is pointless unless the unit is extremely heavy and large and
cannot be anchored economically using the higher values.

I am really looking forward to a time history analysis in sap2000 to
figue out the period of of a 600lb AC unit.
Does anyone think A Non-Linear Push over Analysis of the unit is
appropriate? Comments . . .

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:	La Count, Curt [SMTP:Curt.LaCount(--nospam--at)Jacobs.com]
> Sent:	Friday, August 27, 1999 11:54 AM
> To:	'seaint'
> Subject:	FW: Table 16-O - Horizontal Force Factors, ap and Rp
> 
> Gerald,
> 
> I believe that the criteria for rigidity for elements is .06 second
> fundamental period.  By my experience, there are not very many
> elements that
> meet this definition.  Mostly rugged pumps or boilers.  When you
> examine the
> period, remember to include all the significant components in the load
> path
> that provide flexibility.
> 
> Curt La Count
> Jacobs Engineering
> Portland, OR
>  ----------
> From: Gerard Madden
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: Table 16-O - Horizontal Force Factors, ap and Rp
> Date: Friday, August 27, 1999 11:25AM
> 
> 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
> 
> 
>