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Re: IDR

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Tri-service manual is better known as "technical manual -- Seismic
Design guidelines for Essential Buildings, Feb., 1986 Army TM
5-809-10-1, Navy NABFAC P-355.1, Air Force AFM 88-3, Chap.13 ,section A.
The manual is published by the departments of Army, Navy and Air Force.
I forgot how I got the manual, try university library first. 

MCE is Maximum credible earthquake that has a site acceleration level
associated with exceedance probabilities of 2% in 50 years, or better
know as 2000 year earthquake. This is for structures near fault site. 

MPE is Maximum probable earthquake.

In general, if your structure is not near fault site, I would use a
probabilistic response spectrum that has an exceedance probabilities of
10% in 50 years, or better know as 475 year earthquake.

Tom Chiu, SE
Thomas Engineering


Tom Long wrote:
> 
> Thank you for your response:
> 
> What are MCE and MPE and where can I get the Tri-service manual.
> 
> I have considered the push over analysis, we have the budget but not the
> time, very fast track design schedule.
> 
> Thank You
> 
> Tom Long
> Asia
> 
>         -----Original Message-----
>         From:   Tom Chiu [SMTP:Tomchiu(--nospam--at)worldnet.att.net]
>         Sent:   21 January 1998 07:31
>         To:     seaoc(--nospam--at)seaoc.org
>         Subject:        Re: IDR
> 
>         You should do it both ways:
> 
>         1.  Scale the dynamic analysis results by the factor of UBC base
>         shear/Dynamic base shear and do a Code level stress check.
> 
>         2.  Calculate the Dynamic demand/capacity ratios of the members
> and
>         compare them to acceptable D/C factors for various level of
> earthquakes,
>         such as MCE, MPE etc. Tri-service manual has a list of
> acceptable D/C
>         factors that you can use for reference.
> 
>         3.  If you have enough budget, you can also go a step further to
> do a
>         Push-over analysis to find out the inelastic responses of the
> structure,
>         to see if there is a collapse potential or not.
> 
>         Good luck,
>         Tom Chiu, SE
> 
>         Tom Long wrote:
>         >
>         > We are designing a new 5 level airport in Manila, 188,000 m2.
> The type


>         > of construction is concrete flat plate slab with drop panels.
> We are
>         > using SAP2000 to analyze the structure.  After we perform the
> analysis
>         > and get the seismic forces from the response spectra analysis,
> should we
>         > apply an IDR to reduce the forces before we compare them with
> the
>         > capacity of the elements, or should we compare the d/c ratio
> to a
>         > acceptable factor for the type of structure.
>         >
>         > Or in another case should we follow the UBC and just scale the
> results
>         > from the dynamic analysis.
>         >
>         > Thank you
>         >
>         > Best regards,
>         > Tom Long
>         > Asia
>         >