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Re: Response Spectrum Analysis

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I would say it is also dependant on how your analysis program interpolates
between points that you specify.  If it does linear interpolation, then you
will want to use a tighter spacing.  I have only used RISA and I know RISA
will use log interpolation between points.  This tended to allow me to use
fewer input points.

Hope this helps,

Scott Maxwell

At 11:47 AM 02/04/2000 -0600, you wrote:
>I am doing a response spectrum analysis of a steel covered playground. I am
>using an older version of SAP2000 that has the 94 UBC response spectrum
>functions for soil types S1, S2, S3. I would like to manually input a
>response spectrum from the 97UBC. I understand that when T = 0, Ca = 1.00
>and from To through Ts Ca = 2.5. What I am not clear about are the points in
>between. I know that when T>Ts, Ca =Cv/T, but I was not sure what increments
>of T should be used. I just used increments of 1.00. after Ts. I have
>generated the response spectrum curve from the 97UBC as follows:
>Cv = 0.54
>Ca = 0.36
>T	Ca
>0	1
>.12	2.5
>.60	2.5
>1.6	0.34
>2.6	0.21
>3.6	0.15
>4.6	0.12
>5.6	0.10
>6.6	0.08
>7.6	0.07
>8.6	0.06
>9.6	0.06
>Is this correct? or, should I figure out an equal number of increments from
>Ts = 1.6 to T = 10? Does someone have an example function that I could look
>at? What parameters are typically used for the response spectrum analysis
>using SAP2000?
>Thanks in advance,
>Gina T. Gobo, E.I.T.
>Structural Engineering
>DLR Group
>Ph. 206.461.6000
>Fax 206.461.6049