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Re: Equipment Anchorage

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Just a thought. Are you sure that's not an ASHRAE provision?

William L. Polhemus, Jr. P.E.


> On Nov 26, 2013, at 4:15 PM, <lrhauer(--nospam--at)> wrote:
> I am designing the support of some roof top mounted mechanical equipment,
> (on an existing roof), that is supported by vibration isolators and,
> therefore, I have to amplify the seismic horizontal forces by 2.5, (Table
> 13.6-1 of the ASCE 7-05). These amplified forces would be used for the
> equipment anchorage to the platform and the platform to the roof framing.
> But, I somehow remember that in checking the existing roof framing the Ap
> can be reduced down to 1.0 from 2.5- it is only the connections that need
> to have the Ap of 2.5 used. But, I can’t seem to find this exception
> anywhere in the ASCE, (or ’10 CBC).
> Can anyone help?
> Thanks in advance,
> Larry Hauer, S.E.

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