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Re: OSHPD

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You, didn't say, but I assume you got 1997 UBC Fp = 3.3Wp by using the very
conservative Equation 32-1 with Na = 1.5, Ca = 0.44Na, and Ip = 1.25.
Putting yourself on the worst soil in the near-fault zone is definitely the
worst case.  Note that Ip = 1.50 not 1.25, and your worst case value should
really be 3.96Wp.  To compare with the ASD provisions of the 1994 UBC,
divide by 1.4 and you have 2.83Wp.

To get some relief, you should become familiar with the more precise
Equation 32-2.  Select values of ap and Rp from table 16-0.  Typical values
are 1.0 and 3.0.  At the building roof, still on the worst soil, still in
the near-fault zone, Equation 32-2 would now give you 1.32Wp.   To compare
with the ASD provisions of the 1994 UBC, divide by 1.4 and you have 0.94Wp.

Remember 1.5 of the 1997 values are because you are assuming that you are
less than 2 km from the San Andreas Fault.  Hopefully this is not a valid
assumption for OSHPD facilities.  Taking out the near fault factor of 1.5
gets you down to 0.63Wp on a 1994 UBC basis.

The ap value is the dynamic factor for "flexible" components.  You can use
the tabulated values from UBC Table 16-O.  As an alternate you can evaluate
the fundamental period of both the component and the supporting structure
and determine the "tuning factor" for 5% damping.  Of course this may be
difficult since all of the supporting structures will have different
periods.

It seems that your client may be paying an anchorage penalty by wanting the
same anchorage regardless of site location, and equipment location within
the building.  That's the penalty for not willing to pay for some
site-specific engineering calculations.

Rick Drake, SE
Fluor Daniel, Aliso Viejo, CA

***********************************



                                                                                                                   
                    Matt Jordan                                                                                    
                    <MattJ@crjarch.      To:     "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>                         
                    com>                                                                                           
                    11/09/01 12:50       cc:                                                                       
                    PM                                                                                             
                    Please respond       Subject:     OSHPD.                                                       
                    to seaint                                                                                      
                                                                                                                 . 
                                                                                                                   




We sometimes do equipment anchorage calcs for hospital equipment
manufacturer for submittal to CA state OSHPD. The anchorage was governed by
CA code 1630B, based on '94 code values. I've just found out that they are
adopting sec. 1632 of "97 code in Jan.
The equip. can go anywhere in CA so i can only assume all worse case
values.
What was Fp=.45Wp will go to Fp=3.3Wp !!
For OSHPD the Fvert. =1/3 Fp so now the vertical component alone is greater
than the weight of the equipment !!

Is there any relief in sight ? Throw away the wedge anchors and only use
thru-bolts?

Related to this, does anyone know about shake table testing for equipment
per ICBO AC156 ?
Who does it, what's it cost, what do they give you etc. ? (will it prove Ap
less than 2.5)

regards
Matt Jordan S.E.
CA

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