Rp, ap, and omega-zero are determined for non-structural components using the tables in Chapter 13. Displacements for non-structural components are calculated using EQ 13.3-6 in Section 13.3.2 and has no Cd factor. The reference in EQ 13.3-8 for displacements using Chapter 12 is used when determining relative displacements between structures in which case you'd use the appropriate factors for the structures themselves. Since the component being considered is non-structural, it is assumed that it "goes along for the ride" being forced to deform to meet the displacements of the structures to which it's attached. It's a bit confusing, but in effect, you're not considering the deformation behavior of the non-structural component itself. Rather, you are just looking at the displacement that it would undergo to remain attached to the structural systems supporting it. Hope this helps.
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Cliff Jones P.E., S.E., M.ASCE
Jensen Hughes
Portland OR
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Original Message:
Sent: 12-14-2018 15:22
From: Anami Bingi
Subject: R and Cd Factors
What about Chapter 13? I am looking at seismic separation between two non structural components. Eqn 13.3-8 directs me to Chapter 12 and there's no case in Table 12.2-1 that exactly defines my non structural components. Do I use the same Rp/I value as Cd/I value to amplify my displacement?
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Anami Bingi EIT, A.M.ASCE
Staff Professional II
Kleinfelder
San Diego CA
(424)402-7067
Original Message:
Sent: 12-01-2018 06:44
From: Jose Albaine
Subject: R and Cd Factors
In order to answer your question, I recommend the attached link provides a good background on these factors and their relationships
https://www.structuremag.org/wp-content/uploads/2014/08/C-GuestCol-SeismicDesign-SEAOC-Sept081.pdf
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J.M. Albaine P.E., M.ASCE
Consulting Engr
JM Albaine Engineering, LLC
Waterford CT
(203) 447-0235
Original Message:
Sent: 11-30-2018 16:01
From: Elizabeth Davalos
Subject: R and Cd Factors
Can anyone explain the relation between the R and Cd factors? Where does the Cd factor come from? I understand that the R factor is the force reduction factor due to the ductility of the system, and the Cd factor is the way to return up to the real deformation of the system. However, I still have questions about the relation between theses two factors, and how the Cd factor came to be lower than the R factor?
Thank you
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Elizabeth Davalos A.M.ASCE
Constructora Cautin SA de CV
Zapopan
5233 36820633
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